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Taxonomic differences among closely related pines Pinus sylvestris, P. mugo, P. uncinata, P. rotundata and P. uliginosa as revealed in needle sclerenchyma cells
Abstract
The purpose of the present study was to test the taxonomic value of sclerenchyma in distinguishing Pinus sylvestris and P. mugo, P. uncinata, P. rotundata and P. uliginosa, all representing the subsection Sylvestres within the genus Pinus. Thirty-six samples were gathered in natural populations. Every sample was represented with 30 individuals, every individual with 10 brachyblasts. Three types of sclerenchymatic cells surrounding the resin canals and four between vascular bundles were distinguished. Relations among samples and taxa were verified using discriminant analysis and clustering based on Euclidean distances. The types of sclerenchymatic cells surrounding the resin canals and located between the vascular bundles differentiate the compared taxa when used as average frequencies but are extremely variable and do not allow the classification of every individual. The study demonstrated that the type of sclerenchymatic cells surrounding the resin canals and between the vascular bundles in needles could have an important taxonomic value in distinguishing the taxa of two-needle pines of the subsection Sylvestres in Europe at the population level. The distinguishing of individuals was difficult because of very high variation of sclerenchyma characters.
... The hybrids between the taxa of the P. mugo complex and P. sylvestris in the wild state have been traditionally reported as morphologically intermediate individuals ( [15,16] and the literature cited herein). The biometric studies were conducted to verify the presence of hybrid individuals or even populations [17][18][19][20][21][22][23][24][25]. However, the unequivocal identification of hybrids is difficult based on morphological and anatomical characteristics alone. ...
... We characterized two-year-old needles using a set of traits (Table S5), following the procedures described by Boratyńska et al. [56] and Boratyńska and Boratyński [23]. Every individual was characterized using the average measurements of five needles, each from a different dwarf shoot (i.e., the morphological structure in Conifers from which needles in fascicles of 2-5 grow together). ...
... Every individual was characterized using the average measurements of five needles, each from a different dwarf shoot (i.e., the morphological structure in Conifers from which needles in fascicles of 2-5 grow together). The anatomical characteristics were measured and/or evaluated on the preparations from the central part of the needle [21,23,55,56,83]. ...
Scots pine (Pinus sylvestris L.) and the taxa from the P. mugo complex can hybridize in the contact zones and produce fertile hybrids. A unique example of an early Holocene relict population of P. sylvestris and P. uliginosa (a taxon from the P. mugo complex) growing on the tops of Jurassic sandstone rocks is located in Błędne Skały (Sudetes). Phenotypically, there are trees resembling P. sylvestris, P. uliginosa and intermediate forms between them. We expected that some of P. sylvestris and/or P. uliginosa-like trees could be in fact cryptic hybrids resembling one of the parental phenotypes. To address this question, we examined randomly sampled individuals, using a set of plastid (cpDNA), nuclear (nDNA) and mitochondrial (mtDNA) markers as well as biometric characteristics of needles and cones. The results were compared to the same measurements of allopatric reference populations of the P. sylvestris and the P. mugo complex (Pinus mugo s.s, P. uncinata and P. uliginosa). We detected cpDNA barcodes of the P. mugo complex in most individuals with the P. sylvestris phenotype, while we did not detect cpDNA diagnostic of P. sylvestris within P. uliginosa-like trees. These results indicate the presence of cryptic hybrids of the P. sylvestris phenotype. We found only three typical P. sylvestris individuals that were clustered with the species reference populations based on needle and cone characteristics. Most trees showed intermediate characteristics between P. sylvestris and P. uliginosa-like trees, indicating intensive and probably long-lasting hybridization of the taxa at this area and subsequent gene erosion of parental species.
... Research to date has focused mostly on peat bog pine evolutionary history and processes shaping its genetic structure, especially in the context of the species protection. Nonetheless, these studies were mainly based on morphological features of needles and cones (Boratynska and Boratynski 2007;Boratynska and Lewandowska 2009) and on isoenzymes (Siedlewska and Prus-Głowacki 1995;Prus-Glowacki et al. 1998;Wachowiak and Prus-Glowacki 2009), and they were often restricted to single population and/or individuals. Studies based on morphological data place peat bog pine together with other closely related pine species from the P. mugo complex including dwarf mountain pine (P. ...
... mugo) from mountain regions of Central and Western Europe and mountain pine (Pinus uncinata) from Iberian Peninsula (Christensen 1987;Hamernik and Musil 2007). However, the taxa exhibit also some similarity at biometric and biochemical traits to Pinus sylvestris (Boratynska and Boratynski 2007) and close relationship between these taxa is reflected in phylogeny of the genus (Grotkopp et al. 2004;Gernandt et al. 2005). ...
... Shared characteristics at some traits led the authors to hypothesis that P. uliginosa might be a marginal population of P. uncinata (Krzakowa et al. 1984) or possibly ancient, stabilized hybrid between P. mugo and P. sylvestris (Lewandowski et al. 2000;Boratynska and Boratynski 2007). Some indication of relatively recent divergence of peat bog pine from other taxa from the P. mugo complex was found at sequence variation at nuclear genes (Wachowiak et al. 2011); however, the exact genetic relationship between the taxa is not conclusive. ...
Estimates of genetic differentiation at intra-and interspecific level are often hindered by the lack of suitable molecular markers. Low phylogeographic resolution limits development of appropriate conservation strategies especially in case of endangered forest tree species with small and disjunct distribution. In this study, we assessed fine-scale genetic structure of relict and endangered peat bog pine (Pinus uliginosa) and two other closely related European pine species (Pinus mugo and Pinus uncinata) using a set of 15 newly developed maternally inherited and seed-mediated mitochondrial DNA (mtDNA) markers and two previously known polymorphic mtDNA regions (nad1, nad7). Three main groups, corresponding in general to three investigated species were revealed in the haplotype network analysis. However, only P. uncinata was clearly distinct at all levels of analysis, whereas great genetic similarity and haplotype sharing was observed between P. uliginosa and P. mugo. Strong phylogeographic structure was found in P. uliginosa that showed high differentiation at relatively short geographical distance among populations and the existence of mitochondrial lineages of different evolutionary history. Hybridization with other pine species has likely contributed to genetic differentiation of P. uliginosa as indicated by contemporary distribution of mtDNA haplotypes. The research emphasizes the importance of accurate assessments of genetic structure of endangered species with complex evolutionary history for development of efficient conservation strategies.
... La información disponible ha sido utilizada en algunas de las propuestas de clasificación y relaciones filogenéticas realizadas para el género Price et al., 1998). Los trabajos publicados hasta la fecha también ofrecen información taxonómica suficiente para, en ciertos casos, identificar algunas de sus especies (Ickert-Bond, 2000;Boratyńska & Boratyński, 2007). Sin embargo esto no se extiende a todas las especies que habitan en el suroeste de Europa, por lo que las seis especies espontáneas en la península Ibérica no podrían diferenciarse a través de rasgos epidérmicos. ...
... Todos ellos se clasifican dentro del subgénero Pinus, disponen sus acículas pareadas en los braquiblastos, y presentan bandas estomáticas tanto en el haz como en el envés de la hoja . Al margen de estas semejanzas, estudios taxonómicos basados en sus rasgos epidérmicos concluyen que se pueden distinguir algunas de estas especies a partir de caracteres como el anillo de Florin, el grosor de las células epidérmicas o la forma y disposición de las células subsidiarias del complejo estomático Boratyńska & Bobowicz, 2001;Boratyńska & Boratyński, 2007). Sin embargo, estos trabajos han analizado los taxones ibéricos del género Pinus por separado o en grupos parciales , o bien incluyen caracteres difícilmente observables en material fósil (Boratyńska & Bobowicz, 2001;Boratyńska & Boratyński, 2007). ...
... Al margen de estas semejanzas, estudios taxonómicos basados en sus rasgos epidérmicos concluyen que se pueden distinguir algunas de estas especies a partir de caracteres como el anillo de Florin, el grosor de las células epidérmicas o la forma y disposición de las células subsidiarias del complejo estomático Boratyńska & Bobowicz, 2001;Boratyńska & Boratyński, 2007). Sin embargo, estos trabajos han analizado los taxones ibéricos del género Pinus por separado o en grupos parciales , o bien incluyen caracteres difícilmente observables en material fósil (Boratyńska & Bobowicz, 2001;Boratyńska & Boratyński, 2007). ...
Unlike pollen and wood remains, the cuticular analysis of leaf macroremains more
commonly provides of specific taxonomic information. Although some leaf-based keys
and descriptions are available to identify leaf remains (e.g. Fagaceae), needle fragments
of Iberian pines cannot be identify to the species level due to the lack of detailed
descriptions.
Well preserved pine cuticles (and their stomata) are found in many Iberian
palaeobotanical sites. This motivated our study to report the value of the epidermis of
needles for taxonomic differentiation of the six species of Pinus that grow
spontaneously in the Iberian Peninsula (P. uncinata Ramon ex DC., P. sylvestris L., P.
nigra J.F. Arnold, P. pinaster Aiton, P. pinea L. and P. halepensis Mill). Based on the
study of present pine populations, cuticular and stomatal analyses were performed. To
ensure the applicability of the study on fossil leaves, the methodology was tested in
Holocene material from two different Iberian sites.
To define the sampling procedure, a pilot study was carried out on one population from
each of the six taxa, where up to 17 variables were studied. A high variability was found
within needles in comparison to the variability between needles from the same tree, or
even between trees from the same population. Additionally, no significant differences
were found between sun and shade needles from the same tree. Therefore, the final
sample design was performed on three natural populations from each taxon across its
worldwide distribution (including at least one Iberian locality). On each population,
three trees were randomly sampled, studying three needles from each individual. Every
leaf was macerated, cleaned, and mounted on slides for its study with the aid of the
optical microscope. Epidermis and ten stomata were analyzed on every slide. Principal
components analysis, cluster analyses and discriminant analyses were applied on every
stomatal variable. Variance analyses were used for the study of the pore (epistomatal
chamber opening) size. Additionally, the information provided by the scanning electron
microscope improved the interpretation of the cuticular features.
The number of subsidiary cells of the stomatal complex, their relative size, shapes and
arrangements, and the size of the pore, allow five species/groups to be defined: P.
sylvestris, P. pinaster, P. pinea, P. halepensis and P. gr. uncinata-nigra. The frequency
of solitary lateral subsidiary cells and the pore size provide a means of distinguishing P.
uncinata from P. nigra, although the results cannot be considered entirely reliable.
Statistical analysis of the stomatal variables showed trends towards the taxonomic
differentiation, but they provided modest likelihood results. The results of the cuticular
analysis applied on needle remains from the two Holocene sites showed the suitability
of our study for their taxonomic identification.
Besides, cross section techniques were applied on needles with different preservation
condition. The experiment showed the difficulty of obtaining un-deformed cross
sections with degraded material. However, the information provided by the cross
section is useful to distinguish between P. nigra and P. uncinata.
... All of the other needle characteristics were assessed after the samples were preserved in 70% ethanol. A detailed description of the sampling and measurement procedures can be found in Boratynska & Bobowicz (2000) and Boratynska & Boratynski (2007). ...
... We also hypothesise that the gene pool of A1 might have been affected by gene flow from Pinus uncinata (Ramond) Domin that grows in the Western Alps and in the Pyrenees as shown by Heuertz et al. (2010). This possibility was discussed by Boratynska & Boratynski (2007) and Boratynska et al. (2015). Finally, APN may have originated from an Apennine glacial refugium with limited expansion into the Alps. ...
... The easternmost populations of P. mugo can be distin-guished from the others by the types of sclerenchyma cells between the vascular bundles and around the resin canals of needles. The variability of needle sclerenchyma cell types and their utility in distinguishing the taxa of two-needle pines in the subsection Sylvestres in Europe at the population level has already been ascertained by Boratynska & Boratynski (2007). Nevertheless, it is unknown whether these traits have any adaptive importance. ...
In this study, range-wide genetic variation was analysed in 553 Pinus mugo Turra (dwarf mountain pine) individuals from 21 locations using 11 chloroplast microsatellites. Our main goal was to assess the spatial distribution of neutral genetic variation. We also used data from a previous study on the morphological variation of needles from 18 stands of P. mugo. In total, 22 needle characteristics were reanalysed and compared to microsatellite data to describe the distribution of morphological variation in the context of neutral genetic variation. We hypothesised that the chloroplast microsatellite and needle trait variation patterns would not entirely overlap. The results indicate the recent divergence of P. mugo populations derived from a formerly larger distribution. We identified 4 genetic and 3 morphological clusters whose spatial distribution overlapped only to some extent. The distribution of genetic variation showed a south-north pattern with signs of admixture in the Alps and Carpathians. Two south-westernmost stands from Italy were evidently isolated from the others. In contrast, morphological variation tended to display a west-east pattern. A separate group based on needle traits was formed mostly by eastern stands and was not observed by microsatellite analysis. In addition, a few needle characteristics significantly correlated with longitude and climate variables. These findings suggest that eastern populations of P. mugo may be of different origin and/or that some needle characteristics may be adaptively important in these locations. The potential roles of past demographic events, phenotypic plasticity and local adaptation in shaping the patterns of genetic and morpho logical variation in P. mugo are discussed.
... The ANOVA additionally found that NCR did not distinguish taxa (Table S2, see online supplemental material). The abovementioned characteristics either did not differ, or differed slightly between pairs of populations of these three taxa (Boraty nska & Bobowicz, 2001;Boraty nska & Boraty nski, 2007;Boraty nska et al., , 2011. The differences between pairs of taxa and their significance depended on the origin of compared populations, especially for populations of P. uliginosa. ...
... The differences between pairs of taxa and their significance depended on the origin of compared populations, especially for populations of P. uliginosa. Despite this, the set of characters that includes NL, NSRC, NW, NT, DVB, WE, MC, NT/ NW, SCVB, TCVB and FCRC allows P. mugo s. s., P. uncinata and P. uliginosa to be distinguished with a very high probability (see also Boraty nska & Boraty nski, 2007;Boraty nska et al., 2011). In general, P. uncinata had the largest needles (highest values of NL, NW and NT), with the greatest distance between vascular bundles, the highest Marcets coefficient (DVB, MC) and the highest percentage of thin walled-cells between vascular bundles (TCVB). ...
... The frequent polycormic tree growth of P. uliginosa, which is intermediate between the monocormic growth of P. uncinata and the shrubby form of P. mugo s. s., and the intermediate form of the cones were the features that distinguished between them (Amaral Franco, 1986;Christensen, 1987a;Gaussen et al., 1964). Several biometric studies have indicated differences between the needles of P. mugo s. s., P. uncinata and P. uliginosa (Boraty nska & Bobowicz, 2001;Boraty nska & Boraty nski, 2007;Boraty nska et al., 2011) and in cone characteristics (Boraty nska et al., 2011Marcysiak & Boraty nski, 2007). The results reported to date have indicated a close relationship of P. uliginosa to P. uncinata in terms of the sclerenchymatic cell types between vascular bundles and around the resin canals in the needle (Boraty nska & Boraty nski, 2007), but a closer association with P. sylvestris than to P. uncinata or P. mugo s. s. in cone characteristics (Boraty nska et al., 2011;Marcysiak & Boraty nski, 2007). ...
The phenotypic differentiation of Pinus mugo complex was verified using 31 populations of P. mugo sensu stricto, 11 of P. uncinata, five of P. uliginosa, one of the potential hybrids P. uliginosa × P. mugo and three of P. sylvestris, the latter as a control. The 22 morphological and anatomical needle characteristics were measured and statistically examined to describe the taxa and the population within the taxa differentiation. All the taxa of the P. mugo complex differed significantly from P. sylvestris in most of the verified needle characteristics. Within P. mugo complex, populations of P. uncinata were clearly distinguished from P. mugo s. s. The population of potential hybrid origin was the most similar to P. uliginosa. Populations of the latter taxon were strongly differentiated; some of them were closer to P. uncinata, and others to P. mugo s. s. Within the whole sampled data, three geographic groups of populations were detected: the first included P. uncinata and two of P. uliginosa, the second contained East and South Carpathian P. mugo s. s. with the presumed hybrid population, and the third contained all the other populations of P. mugo s. s. and P. uliginosa. Within P. mugo s. s., the Sudetan populations formed a separate group. Pinus uncinata from the Pyrenees reflected a high level of differentiation. The marginal populations of this taxon (Cebollera, Gúdar, Massif Central) also differed from those in the Pyrenees. The phenotypic differentiation of taxa and populations appeared similar to that which was detected based on cpDNA markers.
... A high level of differences in chloroplast microsatellite loci between the Carpathians, Sudetes and Alps was recently described (Dzialuk et al. 2012), but rather low at selected nucleotide loci (Wachowiak et al. 2013). The significant morphological differences between P. mugo from the Carpathians, Sudetes and Abruzzi Mts. were also found (Staszkiewicz and Tyszkiewicz 1976;Boratyńska et al. 2005;Boratyńska and Boratyński 2007). ...
... The needle traits were selected from published papers on P. mugo agg. taxonomy (Boratyńska and Bobowicz 2001;Boratyńska and Boratyński 2007), the cone traits from papers concerning P. sylvestris (Staszkiewicz 1968) and P. mugo agg. variation and taxonomy (Marcysiak and Boratyński 2007). ...
... Generally, cone characters are more variable than those of needles (Boratyńska et al. 2005), when the frequencies of sclerenchyma cells between vascular bundles and around resin canals are excluded. These data are strongly biased and extremely variable (Boratyńska and Boratyński 2007), which is also expressed in our data ( Table 2). ...
Divergence in genetic as well as phenotypic structures can be expected in species with disjunctive geographic ranges and restricted gene flow among isolated populations. Dwarf mountain pine has such a disjunctive geographic range in the mountains of Central Europe. We hypothesised that populations of Pinus mugo from the Giant Mts. differ from Alpine and Carpathian populations to a greater extent than differentiation within these regions; furthermore, these differences would be detectable at both the genetic and phenotypic levels. To verify this hypothesis, the diversity and differentiation within and among eleven populations from the Giant Mts., Carpathians and Alps were analysed using 19 isozyme isozyme loci, 17 needle and 15 cone morphological characters. Moreover, the data on 10 chloroplast microsatellites used in the previous study, were reanalysed. The differences between the three regions were greater than among populations within them. The microsatellites and isozymes clearly differentiated between regions, while in the multivariate analyses of cone and needle characters the Alpine and Carpathian populations were intermingled but distinct from those sampled in the Giant Mts. The significant genetic structuring among regions may result from an ancient fragmentation and long lasting geographic isolation between the Giant Mts., Alps and Tatras. The populations from the Giant Mts., the northernmost within the geographic range of P. mugo, presented lower level of genetic variation then those from the Alps and Carpathians. The pattern of genetic structure observed in dwarf mountain pine may be characteristic of wind-pollinated trees with a disjunctive geographic distribution
... The aims of this study were: 1) to verify the influence of the tree-like versus shrubby growth form to the morphological characteristics of cones and morphological and anatomical characteristics of needles; and 2) to test the taxonomic status of the tree-like specimens of mountain pine from the Mshana peat bog using the morphological characteristics of the cones and morphological and anatomical characteristics of the needles (Szweykowski 1969;Staszkiewicz and Tyszkiewicz 1972;Boratyñska and Bobowicz 2000;Boratyñska and Boratyñski 2007;Marcysiak and Boratyñski 2007;Boratyñska and Lewandowska 2009). ...
... The 22 traits of needles and 16 of cones were measured and/or evaluated (Table 2) following procedures and using methods described in previous works (Szweykowski 1969;Tyszkiewicz 1969, 1972;Boratyñska and Bobowicz 2000;Marcysiak et al. 2003;Marcysiak 2004;Marcysiak and Boratyñski 2007;Boratyñska and Boratyñski 2007;). ...
... All other analysed characters showed no differences between the compared populations ( Table 2). In the Sudetes, needle length and width, number of stomata rows on the flat (adaxial) side of the needle, ne-edle thickness, distance between vascular bundles, thickness of epidermal cells, stomatal rows ratio, needle thickness/width ratio, epidermis cell width/thickness ratio and percentages of all types of sclerenchyma cells around the resin canals and between vascular bundles (character 1, 7, 3, 8, 9, 10, 16, 18, 20 and 21A, 21B, respectively) also revealed statistically significant differences between P. mugo and P. uliginosa Boratyñska and Boratyñski 2007;Boratyñska and Lewandowska 2009). This indicates a higher level of similarity between tree-like pines and shrub of P. mugo from the Mshana peat bog, than of P. uliginosa and P. mugo in the Sudetes. ...
The taxonomie position of the population of tree-like, mostly polycormic individuals of pines from the Mshana peat bog in the Gorgany Mountains (East Carpathians, Ukraine) has been studied on the basis of the morphological characteristics of cones and needles, and anatomical characteristics of the needles. These features have been compared with the surrounding Pinus mugo population as well as P. uliginosa, P. mugo, P. sylvestris and P. uncinata from natural populations of the taxa. Tree-like individuals were found to have the most similar needles to P. uliginosa, but most similar cone characteristics to P. mugo. It was concluded, that the tree-like population has a relic character and can present the trace of the early migration of P. uliginosa from the West and its hybridisation with P. mugo.
... By now, several populations of P. uliginosa from Poland and the Czech Republic have been compared biometrically on the basis of cone characters (Staszkiewicz and Tyszkiewicz 1972). The morphological characteristics of three extant populations of P. uliginosa from Poland were done during last decade, using needle and cone characters Marcysiak et al. 2003;Boratyńska and Boratyński 2007). The most numerous population of the species from "Torfowisko pod Zieleńcem" Nature Reserve in the Bystrzyckie Mountains has not been analyzed so far using multivariate statistical methods. ...
... In particular, the needle measurements methods and characters studied were based on Boratyńska and Bobowicz (2000) and Boratyńska and Boratyński (2007). The length of needles was measured immediately after the collection and then the needles were conserved in the 70% ethanol. ...
... The length of needles was measured immediately after the collection and then the needles were conserved in the 70% ethanol. The other needle characters were taken from the central part of the needle as described in Boratyńska and Bobowicz (2000), Boratyńska et al. (2003) and Boratyńska and Boratyński (2007) (Table 2 and 3). ...
Pinus uliginosa is an interesting taxon from the Pinus mugo complex with controversial systematic
position andspecific characteristics, intermediate among P. mugo, P. uncinata and P. sylvestris. The peat-bog
pine is rare andprotectedin Poland. All its’ known populations have a relict character andare slightly different
from each other. The aim of the present study was comparison of the individuals from the Czarne Bagno of the “Torfowisko pod Zieleńcem” Nature Reserve (Sudetes), determined in the field on the basis of morphological characteristics as Pinus uliginosa, with four samples of this taxon from the northern limits of its range in PolandandGermany andwith Pinus sylvestris, P. mugo and P. uncinata, to verify morphological andtaxonomic relations between them. The material collected from 30 individuals determined as P. uliginosa, was closest to populations of P. uliginosa from the Bory Dolnośląskie, andto P. mugo from the Tatra Mts., concerning the needle characters. The cone characteristics of P. uliginosa individuals from the Czarne Bagno appeared similar to all other of that taxon. In spite of that, the cone characters first of all differentiate P. uliginosa from P. sylvestris, P. mugo and P. uncinata. The combination of needle and cone morphological characters are a good tool to distinguish P. sylvestris, P. uncinata, P. mugo and P. uliginosa with a very high probability.
... Four types of sclerenchyma cell were distinguished between the vascular bundles, as described in Boratyń ska & Boratyń ski (2007): (AA) fibrous cells (Szweykowski, 1969). The set of characters and the method of measurement were based on earlier biometric studies of pine needles generally accepted as diagnostic in distinguishing P. mugo s.l. ...
... from P. sylvestris (Staszkiewicz & Tyszkiewicz, 1976;Boratyń ska, 2002Boratyń ska, , 2004Sobierajska & Boratyń ska, 2008). The width and thickness of the needle, distances between the vascular bundles, shape of epidermal cells, numbers of stomatal rows, numbers of resin canals, and types of sclerenchyma cells around resin canals and between vascular bundles have been indicated previously as being the most discriminatory between P. sylvestris and P. uncinata (Boratyń ska & Bobowicz, 2000, 2001Boratyń ska & Boratyń ski, 2007). ...
... On the basis of biometry, reference individuals of P. uncinata differed at a statistically significant level from P. sylvestris for most morphological and ana- Character 3 S1 S1 S1 S2 tomical traits. One of the most distinctive traits is the shape of the epidermal cells (Boratyń ska & Bobowicz, 2001;Boratyń ska & Boratyń ski, 2007;Muchewicz, 2007), which were found in our study to be more or less rectangular for P. uncinata and almost square for P. sylvestris (width of epidermal cells/thickness of epidermal cells close to 0.5 and about 0.8, respec-tively). The species differ significantly in distance between vascular bundles (about 140-150 mm for P. uncinata and > 200 mm for P. sylvestris), and the difference is within the range reported for other allopatric populations of the species (Boratyń ska & Bobowicz, 2001;Boratyń ska & Hinca, 2003). ...
We tested the performance of molecular markers and biometric traits in the identification of hybrids between closely related mountain pine (Pinus uncinata) and Scots pine (Pinus sylvestris). A plastid DNA marker and a set of morphological and anatomical needle traits were applied in analyses of individuals from several sympatric stands of the species and a single-species' population from southern Europe, used as a reference. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) marker from the plastid trnL–trnF region and morphological and anatomical traits clearly discriminated between the pure species. Significant differences were found between P. uncinata and P. sylvestris, mostly in the shape of epidermal cells and the number of stomata. Four putative hybrids with P. sylvestris morphology, but with P. uncinata plastid DNA haplotypes, were found in a population from Sierra de Gúdar near Valdelinares, the southernmost locality of the latter species in eastern Spain. Discrimination analyses between and within populations placed these individuals on the edge of an agglomeration of P. sylvestris individuals. The results suggest that hybridization between the species is rare, but can result in cryptic hybrids morphologically similar to the maternal species. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 163, 473–485.
... In the past, various studies were conducted on many characteristics of needles but only three analyzed set of characters of needle (needle length and width and height of needle cross-section) have been found to discriminate between C. atlantica, C. libani, C. brevifolia, and C. deodara [3,5,6,49,50]. Recently, Jasińska et al. [10] have reported an additional another set of needle characters (distance between resin canal and vascular bundle, number of the resin canals, tangential dimension of the hypodermal cell, etc.). ...
... Moreover, Vidaković [5] and Farjon [6] have found that the average values of these traits were much bigger and discriminating between these Cedrus species. Several studies reported that these two traits allow the distinction between Pinus mugo sensu stricto, Pinus uliginosa, and Pinus uncinata, respectively, with a very high probability [50,55,56]. In other studies, Huang et al. [57] and Nikolić et al. [58] found a significant percentage variation in the width and the height of the needle between natural populations of P. yunnanensis in Southwest China and P. peuce in Montenegro and Serbia, respectively. ...
Atlas cedar (Cedrus atlantica (Endl.) G. Manetti ex Carrière) is an endemic species in the mountains of North Africa that is attracting international interest in its use in the reforestation of degraded ecosystems. is study aims to investigate and evaluate the morphoanatomical characteristics of needles of four cedar populations localized in the Middle and High Atlas Mountains. Descriptive statistics, analysis of variance (ANOVA), descriptive power, scatter-plot of the discrimination function, scatter-plot of discrimination, and dendrogram of the closest Euclidean distances were made on traits. e results of the linear model of ANOVA nested as population and tree within population suggest the differences statistically significant for the traits measured at a different level. Among these traits, the length of the needle, the width of a vascular bundle including endodermis, and thickness of the wall of hypodermis cell revealed the highest discriminating characters among populations of C. atlantica from the Middle and High Atlas and between the populations of the Middle Atlas. e agglomeration of populations over short Euclidean distances also showed a higher level of differentiation between two ecotypes of C. atlantica not very geographically distant in the Atlas Mountains of Morocco. e ecotype belonging to Aït Oufella and Aït Ayach confers this species a place of choice in the projects of revalorization of the Mediterranean populations, especially in semiarid areas.
... The values obtained for the stomatal density are significantly lower in P. uncinata, while the stomatal size is significantly higher, and the epidermis is significantly thicker. The presence of a thicker epidermis and less stomata in the needles of P. uncinata has been reported in previous works (Boratyńska and Bobowicz 2001), although the absolute values of the variables differ from the literature, probably due to the different environmental conditions and age of the analysed plants (Boratyńska and Bobowicz 2001;Stružková 2002;Sweeney 2004;Boratyńska and Boratyński 2007;Boratyńska et al. 2008;García Á lvarez 2010). All these features provide a better defence against water loss in the needle of P. uncinata, and could be interpreted as an adaptation to frost drought and freeze-thaw events that affect alpine timberline conifers, causing xylem disfunctions by winter embolism (Mayr et al. 2006). ...
... On the other hand, other tissues had similar areas in cross section (areas of the mesophyll, transfusion tissue, phloem and xylem and thickness of the hypodermis and the endodermis). The presence of 'softer' sclerenchyma cells in P. uncinata has also been marked by Boratyńska and Boratyński (2007). ...
Species selection for reforestations can be challenging in habitat protection zones, especially in human transformed landscapes, where nativeness of some species is not easily determined and yet is crucial for knowing whether a species can be used or not. We try to determine whether Pinus uncinata Ramond ex DC was present in the Cantabrian Range (Spain) and whether it could have disappeared recently due to anthropogenic causes. Plant morphology and needle anatomy were characterized in Pinus sylvestris L. and P. uncinata 2-year-old seedlings. An analysis of variance was used for selecting morphological markers capable of discriminating both species. These markers permit the comparison of seedlings coming from the highest zone of Puebla de Lillo relict pinewood (Cantabrian Range) with reference material from Castillo de Vinuesa (Iberian Range). This comparison was firstly made with two multivariate methods, a principal component analysis and a multivariate discriminant analysis. Subsequently, this was corroborated with the detection of a species-specific chloroplast DNA marker. The differences found between both species reflect the better adaptation of P. uncinata to typical highland environment. Several Puebla de Lillo seedlings had P. uncinata type morphology and haplotype, suggesting the presence of this species in the Cantabrian Range until recently. This discovery changes the current interpretation of the zone’s vegetation, enhancing the natural presence of highland open pinewoods. However, human activities (fire and livestock grazing) have driven them to extinction and have favoured the contemporary expansion of heathlands. Based on this P. uncinata case, we discuss how local extinctions can affect management and conservation policies negatively.
... Ten mature brachyblasts undamaged, fully developed with needles with no visible insect and/or fungi damage, from well-illuminated, north-facing parts of the tree crown about 2-3 m above ground level were collected from each tree. After collection, the lengths of the twoyear-old needles were measured, and the plant material was then preserved in 70% ethanol and stored at 20°C until analysis [46,47]. Semidurable preparations from the central part of ten needles representing the ten brachyblasts from each individual in each population were made by a crosssection. ...
The study of morphological and anatomical characteristics of leaves is important for assessing the geographical variation of species. The ecological adaptability of forty individuals from four populations of Cedrus atlantica were studied, based on analysis of morphological and anatomical traits. The results of the Spearman nonparametric coefficient of correlation showed that the number of stomatal lines (NLS) and the length of the needle (NL) are negatively correlated to altitude and positively to latitude and precipitation sums, while the width of the needle (NW), the thickness of the cuticle (CT), and the number of needles per rosette (NN/R) were negatively related to temperature. In addition, the sum of precipitation is negatively correlated with NW. The first two principal components account for 58.18% of the variation. According to Tukey’s test and Kruskal–Wallis test, all populations had at least three characters separating them at a statistically significant variation. Moreover, the hierarchical classification led us to the individualization of three main groups. All these results show an adaptation of the structure of the needles of C. atlantica from Morocco to the geographical position and the climatic conditions of the populations.
... Pyrenean pine is a typical coniferous tree (grows straight and may reach up to 25 m), which occurs from the Alps westward-in the Massif Central, Jura and Vosges, Pyrenees, and a few remote populations inside the Iberian Peninsula (Jalas & Suominen, 1973). Although they are distinguished by a number of other, more subtle traits, for example, phenology, cone size and shape, needle characteristics, and composition of volatiles and allozymes (please, see Table S1; Lewandowski et al., 2000;Monteleone et al., 2006;Boratyńska & Boratyński, 2007;Boratyńska et al., 2015;Wachowiak et al., 2018;Adams & Tashev, 2019), they are often aggregated under the P. mugo complex together with a few less defined groups (Christensen, 1987;Hamerník & Musil, 2007). For simplicity reasons, and following Businský & Kirschner (2010), we call them here separate species. ...
The environment is a powerful selective pressure for sessile organisms, such as plants, and adaptation to the environment is particularly important for long‐lived species, like trees. Despite the importance of adaptive trait variation to the survival and success of trees, the molecular basis of adaptation is still poorly understood. Gene expression patterns in three closely related, but phenotypically and ecologically divergent, pine species were analyzed to detect differentiation that may be associated with their adaptation to distinct environments. Total RNA of Pinus mugo, P. uncinata and P. sylvestris samples grown under common garden conditions was used for de novo transcriptome assembly, providing a new reference dataset that includes species from the taxonomically challenging Pinus mugo complex. Gene expression profiles were found to be very similar with only 121 genes significantly diverged in any of the pairwise species comparisons. Functional annotation of these genes revealed major categories of distinctly expressed transcripts including: wood trait properties, oxidative stress response, and response to abiotic factors such as salinity, drought and temperature. We discuss putative associations between gene expression profiles and adaptation to different environments, for example: upregulation of genes involved in lignin biosynthesis in the species which have adapted to mountainous regions characterized by strong winds and thick snow cover. Our study provides valid candidates for verification of the importance of the gene expression role, in addition to evidence for selection within genomic regions, in the process of ecological divergence and adaptation to higher altitudes in pine taxa. This article is protected by copyright. All rights reserved.
... This should be particularly true of the loci underlying or linked to ecologically important traits, such as plant life form (polycormy vs. monocormy). Given that these morphological differences between P. mugo and P. uliginosa are most likely due to a very limited genomic region or are conditioned ecologically, the individuals of P. mugo morphology growing in a specific environment may still contain a great genomic portion of hybrid architecture [33,[45][46][47]. ...
The genetic structures of the four putative hybrid swarms of Pinus sylvestris × P. mugo in Slovakia were analyzed in terms of individual admixture proportions calculated via inter-primer binding site (iPBS) marker loci. This work aimed to reevaluate the hybrid swarms’ differentiation status as postulated in the previous studies at both population and genomic levels. The study confirmed intermediate divergence of each of the swarms examined. Based on 80-loci hybrid index scores, we have revealed the presence of introgressive and intermediate hybrids with frequencies corresponding to differentiation estimates. Surprisingly, irrespective of individual phenotypes, the most frequent intermediates were found in Sucha Hora (29.5%) and Obsivanka (28.6%) populations, which resemble rather pure P. mugo and were previously considered as bimodal hybrid zones with a negligible amount of hybrids. The remaining hybrid zone population Zuberec seems to be highly introgressed to P. sylvestris, while Tisovnica is clearly inclined to P. mugo. The results and different methodologies are discussed.
... e 2-year-old needles were characterized using 17 morphological and anatomical features (Table 2). e measurement procedures followed those described by Boratyńska et al. (2005), Boratyńska and Boratyński (2007), and Sobierajska et al. (2010). Each individual specimen was characterized on the basis of three needles, each of which came from a different dwarf shoot in the middle of a longer shoot from a well-lit region of the tree's (bush's) crown. ...
Pinus sylvestris (Scots pine) and taxa from the P. mugo (mountain pine) complex hybridize in contact zones producing morphologically-intermediate fertile hybrids. However, the hybrid specimens sometimes express only the P. sylvestris phenotype. Such cryptic hybrids were detected among P. sylvestris and P. uliginosa in the western part of Błędne Skały in the Stołowe Mountains, where the pines grow on the tops of sandstone rocks and phenotypically resemble P. sylvestris, P. uliginosa, and P. mugo. Hybrids with the P. sylvestris phenotype could be potentially present in other relic populations of this species in these mountains. During the present study, the hybrids were identified only in the area of Błędne Skały based on chloroplast and mitochondrial markers, morphological differentiation of various needle and cone traits, and phenotype assessments of the trees during sampling. ese hybrids included three cryptic hybrids of P. sylvestris × P. mugo with the P. sylvestris phenotype and one displaying the phenotype of P. uliginosa. e other populations analyzed represented Scots pine with no evidence of hybridization with P. uliginosa and/or P. mugo. Biometric data on the cone and needle morphology also suggest possible hybridization within the P. mugo complex on Błędne Skały. e results indicate that hybridization takes place in this population but not in neighboring populations despite the possible connection by pollen-mediated gene flow.
... Earlier reports that addressed the genetic relationships between species were focused mainly on the alternative speciation hypothesis of the origin of P. uliginosa from Central Europe, considered either as a marginal population of P. uncinata, a hybrid between P. mugo and P. uncinata, and/or P. mugo and P. sylvestris [35,38] or an example of ancient homoploid hybrid between the later taxa [36,39,40]. However, those studies were based on small sets of molecular markers, lacking detailed phylogenetic analysis, and thus were inconclusive about the divergence history of Scots pine and taxa from the P. mugo complex. ...
Speciation mechanisms, including the role of interspecific gene flow and introgression in the emergence of new species, are the major focus of evolutionary studies. Inference of taxonomic relationship between closely related species may be challenged by past hybridization events, but at the same time, it may provide new knowledge about mechanisms responsible for the maintenance of species integrity despite interspecific gene flow. Here, using nucleotide sequence variation and utilizing a coalescent modeling framework, we tested the role of hybridization and introgression in the evolutionary history of closely related pine taxa from the Pinus mugo complex and P. sylvestris. We compared the patterns of polymorphism and divergence between taxa and found a great overlap of neutral variation within the P. mugo complex. Our phylogeny reconstruction indicated multiple instances of reticulation events in the past, suggesting an important role of interspecific gene flow in the species divergence. The best-fitting model revealed P. mugo and P. uncinata as sister species with basal P. uliginosa and asymmetric migration between all investigated species after their divergence. The magnitude of interspecies gene flow differed greatly, and it was consistently stronger from representatives of P. mugo complex to P. sylvestris than in the opposite direction. The results indicate the prominent role of reticulation evolution in those forest trees and provide a genetic framework to study species integrity maintained by selection and local adaptation.
... Jasińska et al. (2013) ont aussi mentionnés l'existence de ces types de CS chez le genre Cedrus. De même, ces résultats sont en accord avec ceux trouvés parBoratyńska et Boratyński (2007) chez Pinus sylvestris, P. mugo, P. uncinata, P. rotundata et P. uliginosa. D'après les observations microscopiques le sens de disparition des CR est de la base vers le sommet de l'aiguille avec diminution progressive du nombre des cellules de type CT(Fig. ...
L’objectif de cette thèse vise l’identification des caractères morphologiques et
anatomiques adaptatifs permettant de discriminer entre les populations du cèdre Marocaines distantes géographiquement.
... The converted SNPs were found to reflect results from previous studies on inter-and intraspecific relationships in the focal species which, despite morphological, geographical and ecological differentiation, show high genetic similarity based on biometric, biochemical (monoterpenes, isozymes) and molecular markers (Boratyńska & Boratyński, 2007;Lewandowski et al., 2000;Wachowiak, Boratyńska, & Cavers, 2013). The presence of a high number of shared SNPs among the species, as found in comparative transcriptome sequencing (Wachowiak et al., 2015) and candidate gene studies (Wachowiak, Zaborowska, et al., 2018), confirms their close genetic relationships and common ancestry. ...
Pines are some of the most ecologically and economically important tree species in the world, and many have enormous natural distributions or have been extensively planted. However, a lack of rapid genotyping capability is hampering progress in understanding the molecular basis of genetic variation in these species. Here, we deliver an efficient tool for genotyping thousands of single nucleotide polymorphism (SNP) markers across the genome that can be applied to genetic studies in pines. Polymorphisms from resequenced candidate genes and transcriptome sequences of P. sylvestris, P. mugo, P. uncinata, P. uliginosa and P. radiata were used to design a 49,829 SNP array (Axiom_PineGAP, Thermo Fisher). Over a third (34.68 %) of the unigenes identified from the P. sylvestris transcriptome were represented on the array, which was used to screen samples of four pine species. The conversion rate for the array on all samples was 42 % (N = 20,795 SNPs) and was similar for SNPs sourced from resequenced candidate gene and transcriptome sequences. The broad representation of gene ontology (GO) terms by unigenes containing converted SNPs reflected their coverage across the full transcriptome. Over a quarter of successfully converted SNPs were polymorphic among all species, and the data were successful in discriminating among the species and some individual populations. The SNP array provides a valuable new tool to advance genetic studies in these species and demonstrates the effectiveness of the technology for rapid genotyping in species with large and complex genomes.
... The relationships among these taxa and potential speciesspecific determinants for them have been investigated extensively using comparative analysis on needle traits and cones (Boratyńska and Boratyński 2007), the serological methods (Prus-Głowacki et al. 1985), allozymes (Prus-Głowacki et al. 1998;Lewandowski et al. 2000), the chemotaxonomic approach Celiński et al. 2015), ormore recentlyusing DNA markers (Monteleone et al. 2006;Celiński et al. 2017a) and next-generation sequencing (NGS) (Celiński et al. 2017b). ...
The Pinus mugo complex comprises closely related pines in different taxonomic ranks, which commonly occur in major European mountain chains. This large and polymorphic complex has been, and still is, a considerable challenge for taxonomists due to highly variable phenotypical characteristics within particular taxa, ongoing hybridization in sympatric populations, lack of distinct morphological species-specific determinants, and the absence of distinct genetic differentiation among them. Moreover, cytogenetic data on pines from this complex are very scarce. Therefore, in this study, we used C-banding methods and flow cytometric analysis in order to provide new data on karyotypical features and DNA content of three closely-related pines from the Pinus mugo complex, i.e., Pinus mugo (Turra), Pinus uliginosa (Neumann), and Pinus × rhaetica (Brügger) and to gain more insight into the taxonomic relationships between these pines. Our results confirmed that the basic number of chromosome is the same amongst the analyzed taxa (2n = 2x = 24), and that the karyotypes have a similar morphology. The number of secondary constrictions (SCs) and C-banding patterns differed slightly between P. mugo, P. uliginosa and P. × rhaetica. The nuclear DNA content (2C/pg) among analyzed taxa is from 46.41 pg for P. mugo and P. × rhaetica to 46.48 pg for P. uliginosa. For each of these pines, certain taxa-specific cytogenetic determinants were identified. Our results indicate that they may represent two different taxa, and so their names should not be used interchangeably in scientific literature.
... Cependant, les nombreuses études menées par les auteurs d'Europe centrale, surtout polonais et tchèques, démontrent la singularité de Pinus uliginosa au sein du complexe des Pins de montagne. Trois publications récentes illustrent parmi d'autres la validité biologique (13) de ce taxon sur la base de critères anatomiques des aiguilles (Boratyńska et Boratyński, 2007 ; figure 6, p. 610) ou sur le polymorphisme enzymatique : isoen- zymes* des bourgeons (Prus-Glowacki et al., 1998) et alloenzymes* des graines ( Lewandovski et al., 2000 ; figure 7, p. 610). ...
Le complexe des Pins de montagne atteint en Europe centrale un haut degré de diversité morphologique qui se traduit depuis deux siècles par une pléthore d’épithètes spécifiques et infraspécifiques censée nommer tous les types de conifères d’altitude ou de tourbière. L’auteur, à la suite d’une prospection in situ effectuée à l’été 2017, esquisse un panorama écologique et dendrologique des principaux taxons rencontrés d’ouest en est, et suggère des pistes d’amélioration de la nomenclature appliquée jusqu’ici à cet agrégat sur la base de travaux récents ou parfois publiés de longue date. Il propose notamment d’abandonner les binômes Pinus rotundata (le plus souvent synonyme de Pinus uncinata) et Pinus mugo, ce dernier désignant au gré des circonstances soit le Pin rampant, soit l’ensemble du complexe. Il préconise de réserver l’appellation Pinus uliginosa au véritable Pin des marais, et considère que l’ancien binôme Pinus montana serait le plus pertinent au rang supraspécifique pour désigner l’ensemble des Pins de montagne.
... Ex Mirb) are hard to distinguish in the field and in remote sensing imagery. In some cases microbiological analyses (Alvarez et al., 2009;Boratynska and Boratynski, 2007) are required to separate their identity. The microbiological methods provide high taxonomic precision but are inapplicable when, for example, species identification is required in forest inventories over large areas. ...
... Studies on P. mugo have primarily concentrated on the morphology of its cones and needles (e.g. Boratyńska and Boratyński 2007;Boratyńska et al. 2004Boratyńska et al. , 2014Boratyńska et al. , 2015. Populations from the Eastern and Southern Carpathians differ morphologically from the stands in other locations. ...
Twenty-one populations (555 individuals) covering the entire native range of Pinus mugo Turra (dwarf mountain pine) were investigated for genetic variation scored at 13 nuclear microsatellite markers (nSSRs). The main objective of the present study was to determine the genetic structure across the present distribution of the species and locate populations of different genetic compositions. Most of the genetic variation was observed within the populations (95%). The assignment of populations based on Bayesian clustering methods revealed that the Sudeten populations of P. mugo form a separate genetic cluster. These stands have likely been established through the founder effects of Alpine migrants. The distribution and level of SSR polymorphisms, along with no evidence of isolation by distance or phylogeographic structure, indicate that the present populations of P. mugo have diverged relatively recently and originate from a larger glacial distribution of the species. One peripheral stand from Italy had the lowest values of most calculated genetic variation indices. This stand could therefore be more susceptible to genetic drift and a negative impact of predicted environmental changes. We discuss our findings with respect to previously published results on the genetic and morphological variation of P. mugo and with consideration for the conservation genetics of the species.
... Here, we focus on a group of four closely related European pines: Scots pine (Pinus sylvestris L.) and the three taxa comprising the P. mugo complex including P. mugo Turra (dwarf mountain pine), P. uncinata Ramond (mountain pine) and P. uliginosa Neumann (peat-bog pine). These species differ from each other in phenotype, total population size, geographical distribution and ecology, in particular for traits related to dehydrative stress and temperature [6][7][8]. Pinus sylvestris is one of the most ecologically and economically important forest tree species in the world and has the largest distribution of all pines, being found from western Scotland to eastern Siberia and from Turkey and Spain north to the Arctic Circle. It is locally adapted to environmental conditions related to photoperiod and temperature and shows clinal latitudinal variation in timing of bud set and cold hardiness [9]. ...
Pinus sylvestris, P. mugo, P. uliginosa and P. uncinata are closely related but phenotypically and ecologically very distinct European pine species providing an excellent study system for analysis of the genetic basis of adaptive variation and speciation. For comparative genomic analysis of the species, transcriptome sequence was generated for 17 samples collected across the European distribution range using Illumina paired-end sequencing technology.
De novo transcriptome assembly of a reference sample of P. sylvestris contained 40968 unigenes, of which fewer than 0.5% were identified as putative retrotransposon sequences. Based on gene annotation approaches, 19659 contigs were identified and assigned to unique genes covering a broad range of gene ontology categories. About 80% of the reads from each sample were successfully mapped to the reference transcriptome of P. sylvestris. Single nucleotide polymorphisms were identified in 22041-24096 of the unigenes providing a set of ~220-262 k SNPs identified for each species. Very similar levels of nucleotide polymorphism were observed across species (π=0.0044-0.0053) and highest pairwise nucleotide divergence (0.006) was found between P. mugo and P. sylvestris at a common set of unigenes.
The study provides whole transcriptome sequence and a large set of SNPs to advance population and association genetic studies in pines. Our study demonstrates that transcriptome sequencing can be a very useful approach for development of novel genomic resources in species with large and complex genomes.
... However, the marginal southernmost population from Sierra de Gúdar, which was one of the most differentiated P. uncinata populations at plastid SSR loci (Dzialuk et al., 2009;Heuertz et al., 2010), showed no significant differentiation at the nuclear loci studied. In other P. uncinata studies, low differentiation among some Pyreneean populations was reported at allozyme loci (Lewandowski et al., 2000) and sclerenchyma cell types of needles (Boratyń ska & Boratyń ski, 2007). ...
Nucleotide polymorphism at 12 nuclear loci and two mitochondrial gene fragments was studied in three closely related pine species from the Pinus mugo complex in populations across the species distributional range in Europe. Despite large differences in the census sizes of the populations, high and similar levels of nucleotide diversity (θsil = ∼0.013–0.017) were found at nuclear loci in the three pine species. More rapid decay of overall linkage disequilibrium (LD) and recombination to diversity ratio (ρ/θ) was observed across the species distributional range in P. mugo (ρ = 0.0369 ± 0.0028; ρ/θ = ∼2.2) than in P. uncinata (ρ = 0.0054 ± 0.0011; ρ/θ = ∼0.4) and P. uliginosa (ρ = 0.0051 ± 0.0010, ρ/θ = ∼0.4). However, regional groups of P. mugo showed similar levels of LD and ρ/θ ratio to the other species. An excess of rare nucleotide variants was found in P. mugo at four loci, but, overall, the allelic frequency spectrum in the three species did not deviate significantly from neutrality (multilocus Tajima's D = −0.681, D = −0.118 and D = −0.266, P > 0.05, respectively). Bayesian clustering methods showed no clear correspondence of clusters to species or geographical regions. Some differences between populations and species were found in a hierarchical analysis of molecular variance (AMOVA) and in the distribution of the mitochondrial DNA haplotypes, suggesting rather limited gene flow between the taxa and ongoing divergence. As all three pine taxa have similar genetic backgrounds, they form an excellent system for searching for loci involved in adaptive variation and speciation.
... The set of the characters (Table 2) includes those used in the keys to determination of cedars (Gaussen 1964;Maheshwari and Biswas 1970;Krüssmann 1985;Vidaković 1991;Eckenwalder 2009;Marin et al. 2009;Farjon 2010) and detected as discriminating among taxa in the anatomical and morphological examinations of the needle characteristics of pines and firs (Boratyńska and Bobowicz 2001;Boratyńska and Boratyński 2007;Boratyńska and Lewandowska 2009;Dörken and Stützel 2012;Sękiewicz et al. 2012). ...
The main aim of the present study was testing the value of the morphological and anatomical character-istics of the needles in distinguishing Cedrus atlantica, C. libani and C. brevifolia. Nine populations were sampled in their natural habit and 25 characters were used to describe the variation of the brachyblast needles and to analyze the differences between species. The results indicated that morphological and anatomical needle characters provide valuable tools in discrimination of the taxa. The scored differences were statistically significant, as revealed in the Tukey's t test, discrimination analysis and hierarchical analysis of variation. The results support treating C. libani, C. atlantica and C. brevifolia as independent species.
... Beck, peatbog pine (Businský, 1999;Hamerník & Musil, 2007). Pinus sylvestris is closest to P. uncinata with respect to needle sclerenchyma characters (Boratyń ska & Boratyń ski, 2007), whereas its cone morphology more closely resembles that of P. mugo s.s. (Christensen, 1987b;Marcysiak & Boratyń ski, 2007). ...
Aim Our aims were to test whether morphological species of mountain pines were genetically supported in the western part of the distribution range of the Pinus mugo species complex (Pinus mugo Turra sensu lato), to resolve genetically homogeneous clusters of populations, to determine historical demographic processes, and to assess the potential hybridization of mountain pines with Scots pine, Pinus sylvestris L.
Location Populations were sampled in the Iberian System, the Pyrenees, the French Mont Ventoux, Vosges and Jura mountains, the German Black Forest and throughout the Alps. This corresponded to a range-wide sampling for mountain pine sensu stricto (Pinus uncinata Ram.) and to a sampling of the western parts of the ranges of dwarf mountain pine (Pinus mugo Turra sensu stricto) and bog pine/peatbog pine [Pinus rotundata Link/Pinus × pseudopumilio (Willk.) Beck].
Methods In total, 786 individuals of P. mugo sensu lato from 29 natural populations, and 85 individuals of P. sylvestris from four natural populations were genotyped at three chloroplast microsatellites (cpSSRs). Populations were characterized for standard genetic diversity statistics and signs of demographic expansion. Genetic structure was explored using analysis of molecular variance, differentiation statistics and Bayesian analysis of population structure (BAPS).
Results One hundred haplotypes were identified in P. mugo sensu lato. There was a stronger differentiation between geographical regions than between morphologically identified taxa (P. mugo sensu stricto, P. uncinata and P. rotundata/P. ×pseudopumilio). Overall genetic differentiation was weak (GST = 0.070) and displayed a clear phylogeographic structure [NST = 0.263, NST > NST (permuted), P < 0.001]. BAPS identified a Pyrenean and an Alpine gene pool, along with several smaller genetic clusters corresponding to peripheral populations.
Main conclusions The core regions of the Pyrenees and Alps were probably recolonized, respectively by P. uncinata and P. uncinata/P. mugo sensu stricto, from multiple glacial refugia that were well connected by pollen flow within the mountain chains. Pinus rotundata/P. × pseudopumilio populations from the Black Forest, Vosges and Jura mountains were probably recolonized from various glacial populations that kept their genetic distinctiveness despite late glacial and early Holocene expansion. Marginal P. uncinata populations from the Iberian System are compatible with elevational shifts and long-term isolation. The causes of haplotype sharing between P. mugo sensu lato and P. sylvestris require further research.
... Rila and Pirin, and some disjunctions in Italy and the western Alps) (Christensen 1987;Hamerník and Musil 2007), and the western division, encompassing P. uncinata populations distributed on the Iberian mountain ranges, Pyrenees, Massif Central and western Alps (Christensen 1987;Hamerník and Musil 2007). P. mugo s.s. and P. uncinata can be easily distinguished using morphological and anatomical characters in allopatric areas (Boratyńska and Bobowicz 2001;Boratyńska and Boratyński, 2007;Christensen 1987;Marcysiak and Boratyński, 2007),although molecular markers indicate the absence of species differentiation (Heuertz et al. 2010;Monteleone et al. 2006). There are two predominant hypotheses to define this situation taxonomically: the first treats these pines as independent species (Gaussen et al. 1993;Prus-Glowacki et al. 1998), while the second considers them as two P. mugo subspecies, mugo and uncinata (Ramond ex DC. in Lam. and DC.) Domin (Boratyńska and Bobowicz 2001;Christensen 1987). ...
• Introduction
The most common representatives of the European mountain pine complex (Pinus mugo s.l.) are P. mugo s.s. and Pinus uncinata.
• Materials and methods
Genome characterization of P. mugo and P. uncinata was studied using fluorescence in situ hybridization of 5S and 18–5.8–26S rDNA, fluorochrome banding for heterochromatin characterization, and flow cytometry for DNA content measurement.
• Results and discussion
Distribution of 5S and 18S rDNA showed identical patterns for both pine species. In contrast, heterochromatin patterns revealed slight differences in the number and position of bands between these two pines. Genome size analysis of 21 P. mugo populations and one P. uncinata population revealed no significant variations across seven European countries. The mean genome size (2C DNA) for the 21 P. mugo populations was 42.56 ± 0.79 pg, equivalent to 41.62 × 103 Mbp, and ranged from 41.08 to 43.95 pg. No relationships were observed between nuclear DNA content and geographic origin of the studied populations.
• Conclusions
Our results reveal that the mechanisms shaping molecular cytogenetic organization and genome size did not profoundly differentiate the genomes of P. mugo and P. uncinata. Observed variations in heterochromatin patterns indicate ongoing divergence processes in the genomes of the two pines.
... uncinata, the brown fissured bark at the upper stem or greyish-green needles of P. mugo subsp. uncinata were reported [4, 13, 16, 27–32]. ...
We address the problem of spontaneous hybridization between an exotic species Pinus mugo and the native/local P. sylvestris at the seaside spit of Kursiu Nerija in Lithuania. The objective was to identify spontaneous hybrids between P. mugo and P. sylvestris based on morphology traits among the individuals naturally regenerating at the seaside spit. The field inventory was carried out over the entire Lithuanian part of the spit, and 200 individuals morphologically intermediate between P. sylvestris and P. mugo were identified. Based on a weighted trait index, the intermediate individuals were grouped into two groups, one morphologically close to P. sylvestris and another close to P. mugo. The needle micromorphological traits of the putative hybrids were of intermediate values between P. mugo and P. sylvestris. The results provide a strong evidence of spontaneous hybridization between P. mugo and P. sylvestris in Lithuanian seaside spit of Kursiu Nerija.
... damage by wind) and fending off herbivores [26]. The type of sclerenchymatic cells present between the vascular bundles in a particular species and the distance between vascular bundles are considered important taxonomic characteristics in needle pine species [27]. Our results indicated that sclerenchymatic cells in DR and GSR were not the results of environmental pressure, and provided a good way to identify SR and the two terrestrial ecotypes. ...
The adaptational characteristics due to long-term adaptation in the natural habitats of common reed (Phragmites communis Trin.) contrasted considerably among three different ecotypes: dune reed (DR), Gobi salt reed (GSR) and swamp reed (SR). The micromorphologies of leaf adaxial surfaces showed tapered setae and a non-smooth surface in DR, compound papillose structures with wax and hairs in GSR, but only papillose structures for the smooth surface of SR. Anatomical analysis showed that DR and GSR had higher bundle-sheath cell areas and a lower xylem/phloem ratio than SR. There were many sclerenchyma cells in vascular bundle of DR and GSR and crystal idioblasts in all ecotypes. Chloroplasts had ellipsoid shape in SR, but they were attached to the cell wall with oblong shape and contained many starch grains in DR and GSR. Higher concentrations of NO, H(2)O(2) and lipid peroxidation, higher ratio of carotenoids/chlorophyll and higher activities in T-AOC and SOD were found in DR and GSR. Na(+)/K(+)-ATPase and Ca(2+)/Mg(2+)-ATPase activities were greatest in GSR. All these data suggested that the greater relative stress tolerance of DR and GSR was due to a combination of morpho-anatomical adaptational characteristics and physio-chemical responses, and indicated the different mechanisms in their respective natural habitats.
Gymnosperms are a very old and small group of plants compared to angiosperms. Contemporary science recognizes about 650 extant conifers worldwide. This review focuses on species of the Pinaceae family found in Europe. There are 23 species from the genera Abies, Larix, Picea, and Pinus. Some of them are widespread in Europe, but others have fragmented and limited distribution and are classified as relic, endemic, or endangered. The aim of this review is providing cumulative information about the variability of needle morpho-anatomy, terpenes, and n-alkanes, as well as the genetics of the Pinaceae species, native to Europe. The first morpho-anatomical examinations of needles were conducted in the 19th century. A lot of species have been investigated up to now, but the population variability of many conifer species is still not known. The composition and abundance of terpenes differ between genera and families but also within the same genus, pointing to their taxonomic importance. n-Alkanes on the needle wax surfaces of conifers are sometimes very useful markers of species and population variability. The most abundant n-alkanes in Abies species are nonacosane (C29), hentriacontane (C31), or heptacosane (C27), whereas in Larix decidua and the majority of Picea species, C31 is predominant. C31 and C29 are the dominant n-alkanes in the genus Pinus. The most extensive population-genetic studies of European representatives of the Pinaceae family have focused on Abies alba, Picea abies, Pinus nigra, and Pinus sylvestris, but also examined endemic species such as Abies borisii-regis, A. cephalonica, A. nebrodensis, and Picea omorika. These studies hold significant practical value in assessing species’ evolutionary potential, devising strategies for long-term species conservation, identifying centers of diversity, detecting relict and ancestral populations, unveiling cryptic species and hybrids, and elucidating the taxonomic significance of species. These investigations are of great value not only on the biodiversity level, but also on the levels of ecology, physiology, taxonomy, and evolution.
The bog pine, Pinus rotundata Link is a putative hybrid species derived from Pinus uncinata mainly distributed in the western Alps and Pyrenees and Pinus mugo, an eastern European species. It has a scattered and relictual distribution in Bavaria, found in bogs in the pre-alpine region and eastern Bavarian mountains, among them in northeastern Bavaria the Fichtel Mountains (German: Fichtelgebirge) and the Upper Palatinate Forest (German: Oberpfälzer Wald). In this study, we investigated the genetics and cone morphology of 11 northern Bavarian populations using a chloroplast barcode marker (trnL-F) and measuring taxonomic relevant cone characters such as the size of cones and apophyse depth and width. We identified two different genetic variants , mostly occurring sympatrically, differing by one single nucleotide polymorphism (SNP) (G, T) in trnL-F. The genetic variants partly overlap in cone morphology. However, the G-type exhibited stronger hook-shaped apophyses, resembling Pinus uncinata, while the T-type was closer to P. mugo. Distribution models revealed a relationship between genotype frequencies and space, with closer populations being more similar in frequency distributions of genotypes than distant populations. Moreover, the G-type (P. uncinata like plants) was more frequent in areas with harsher climates (higher elevation, shorter vegetation time) whereas the P. mugo like plants dominated at low elevation. Considering the old age and isolation of the relict populations, the polymorphic population structure consisting of at least two distinguishable subtypes is remarkable. Reproductive barriers not detected so far may be still effective within the populations. The rare T-type with P. mugo like cone morphology could be interpreted as a novelty pointing to some degree to hybrid specia-tion by transgression. Zusammenfassung Die Moorspirke, Pinus rotundata Link, ist eine mutmaßli-che Hybridart aus der Haken-Kiefer Pinus uncinata, die hauptsächlich in den Westalpen und Pyrenäen verbreitet ist, und der Latsche Pinus mugo, einer osteuropäischen Art. In Bayern kommt sie zerstreut und als Relikt in Mooren des Voralpenlandes und der ostbayerischen Gebirge vor, darunter im Fichtelgebirge und im Oberpfälzer Wald. Mittels eines Chloroplasten-Barcodemarkers (trnL-F) und anhand der Zapfenmorphologie wurde in dieser Studie die geneti-sche und morphologische Variabilität der Moorspirke in 11 nordbayerischen Populationen untersucht. Taxonomisch relevante Zapfenmerkmale wie die Größe der Zapfen sowie Tiefe und Breite der Apophyse wurden vermessen und mit genetischen Unterschieden korreliert. Wir identifizierten zwei verschiedene genetische Varianten, die meist sympatrisch auftreten und sich durch einen einzigen Nukleotid-Polymor-phismus (SNP) (G, T) im Marker trnL-F unterscheiden. Die genetischen Varianten überschnitten sich teilweise in der Zapfenmorphologie. Der G-Typ wies jedoch stärker hakenför-mige Zapfenschuppen auf, die an Pinus uncinata erinnerten, während der T-Typ näher an P. mugo-Zapfen lag. Verbrei-tungsmodelle ergaben, dass näher aneinander gelegene Populationen sich in der Häufigkeitsverteilung der Genotypen ähnlicher waren als weit voneinander entfernte Populationen. Außerdem war der G-Typ (P. uncinata-ähnliche Pflanzen) in Gebieten mit rauerem Klima (höhere Lage, kürzere Vegeta-tionszeit) häufiger, während die P. mugo-ähnlichen Pflanzen in niederen Lagen dominierten. In Anbetracht der langen geographischen Isolierung der Reliktpopulationen ist die unterschiedliche Populationsstruktur, die aus mindestens zwei unterscheidbaren Subtypen besteht, bemerkenswert. Möglicherweise sind innerhalb der Populationen noch Fortpflanzungsbarrieren wirksam, die bisher nicht entdeckt wurden. Der seltene T-Typ mit einer P. mugo ähnlichen
The morphological features of plants, which were the basis of taxonomic solutions in the past, are now sometimes less appreciated due to the intensive development of genetic methods. The present review looks at the results of the research on the taxonomy of plants carried out by the team led by A. Boratyński. The team characterized the taxonomic and geographical differentiation of some species of the genera Abies, Juniperus, Pinus, Cupressus, Cedrus, as well as several others. Many of these studies were carried out in the Mediterranean area due to its importance for biodiversity. The results allowed unravelling taxonomic ambiguities, emphasizing the importance of geographic barriers in shaping variability, e.g., the Strait of Gibraltar or the Aegean Sea, and highlighting the role of mountain ranges as refuges, e.g., the Taurus and Anti-Taurus Mountains. All of the results obtained with biometrics were confirmed by genetic methods by different authors. Detailed research allowed the publication of a new name, Juniperus thurifera subsp. africana (Maire) Romo & Boratyński, stat. nov., and restoration of species status for the dubious taxon Juniperus canariensis. The review shows that relying on the research of a large number of correctly sampled populations and correctly selected differentiated characteristics of plants allows the generation of reliable results.
Needle structure in Pinus sibirica, P. pumila, and their hybrids was studied by light microscopy. The examined hybrids primarily had mtDNA of P. pumila and cpDNA of P. sibirica. The species differed by all measured traits including needle dimensions, number and position of resin ducts, and mesophyll folding. A hybrid index was calculated by qualitative traits and traits not correlated with needle length, namely closeness of abaxial resin ducts and number of additional cells in the hypodermis. On average, the hybrid index was 3.04, 48.05, and 29.07 in P. sibirica, P. pumila, and hybrids, respectively. The hybrids were characterized by the largest area of the resin ducts compared to the parental species. The most differentiation of the species and hybrids was obtained with discriminant analysis based on needle length, needle width, needle thickness, hybrid index, and resin duct total area. The squared Mahalanobis distance was 114 between the species, 37 between P. sibirica and hybrids, and 24 between P. pumila and hybrids. The greater similarity between hybrids and P. pumila could be the result of maternal effect.
The Pinus mugo complex is a large group of closely related mountain pines, which are an important component of the ecosystems of the most important mountain ranges, such as the Alps, Carpathians and Pyrenees. The phylogenetic relationships between taxa in this complex have been under discussion for many years. Despite the use of many different approaches, they still need to be clarified and supplemented with new data, especially those obtained with high-throughput methods. Therefore, in this study, the complete sequences of the chloroplast genomes of the three most recognized members of the Pinus mugo complex, i.e., Pinus mugo, Pinus rotundata and Pinus uncinata, were sequenced and analyzed to gain new insight into their phylogenetic relationships. Comparative analysis of their complete chloroplast genome sequences revealed several mutational hotspots potentially useful for the genetic identification of taxa from the Pinus mugo complex. Phylogenetic inference based on sixteen complete chloroplast genomes of different coniferous representatives showed that pines from the Pinus mugo complex form one distinct monophyletic group. The results obtained in this study provide new and valuable omics data for further research within the European mountain pine complex. They also indicate which regions may be useful in the search for diagnostic DNA markers for the members of Pinus mugo complex and set the baseline in the conservation of genetic resources of its endangered taxa.
Pinus syvestris from the Iberian Peninsula was biometrically compared, using needle morphological and anatomical characteristics from 15, and cone morphological characteristics from nine natural populations. Samples of Scots pine represent subspecies nevadensis and varieties pyrenaica, catalaunica, and iberica. Analyses included 25 needle and 17 cone characteristics and numerical methods (principal component analysis, discrimination analysis, agglomeration on Euclidean/Mahalanobis’ distances). A strong differences were detected between P. sylvestris subsp. nevadensis when compared to varieties pyrenaica and iberica, and a closer relationship to var. catalaunica in needle characteristics. In cone characteristics, the differences were at a similar level. Alien individuals were found within every taxon and population. Samples from the southern part of Sistema Central had the highest level of alien individuals. The geographic pattern of differentiation resembles patterns previously revealed using molecular and isoenzymatic markers. We could not detect characteristics specific to either P. sylvestris subsp. nevadensis or varieties of P. sylvestris subsp. sylvestris.
Supplemental data for this article is available online at https://doi.org/10.1080/11263504.2021.1922532 .
Variations in the phenotypic characteristics of conifer needles is a consequence of genetic evolution that has been widely used in geographic variation and ecological studies. Although many studies are based on an in situ sampling strategy and generally realize the contribution of environmental effects to variation in needle traits, it is still uncertain which needle traits are most influenced by genetic effects and which are most influenced by the environment. Using both a common garden experiment to eliminate environmental heterogeneity and an in situ sampling strategy, we compared 18 Pinus tabuliformis needle traits among 10 geographical populations. Using both sampling strategies, we found significant differences in needle traits among populations and among individuals within populations. Differences in the “among-population” variance component between the two sampling strategies revealed the environmental contribution among natural populations for each trait. The among-population variance in the following traits exceeded 8%: needle length, number of stomata within 2 mm (NS2), number of stomatal lines on the planar side, number of resin canals (RCN) and the resin canal area (RCA). For the stability of needle traits, NS2, RCN, RCA, ratio of the vascular bundle area to the RCA (VBA/RCA), and MA/RCA differed significantly in more than five provenance changes between the common garden populations and natural populations, which may be susceptible to environmental effects. Conversely, the cross-sectional area, mesophyll area (MA), MA/(VBA + RCA), and MA/VBA were phenotypically stable. Geographic variation patterns and systematic relation of needle traits differed between the two sampling strategies, suggesting that in situ sampling results may reflect environmental effects and deviate statistical parameters for genetic study. Future studies of genetic evolution in the context of geographic variation should be based on appropriate sampling strategies and stable phenotypic traits.
DNA barcoding is a standard and efficient method, frequently used for identification, discrimination and discovery of new species. Although this approach is very useful for classifying the world's biodiversity, little is known about its usefulness in barcoding at lower taxonomic level and its discrimination rate for closely related species, like conifers. In this study, we compared the genetic variation of eight chloroplast DNA barcode regions (matK, rbcL, trnH-psbA, trnL-trnF, rpl20-rps18, trnV, ycf1, ycf2) in 17 conifers - three closely related pines from Pinus mugo complex and 14 more distant conifers representing two genera and four sections of the Pinaceae family. The discrimination rate for a single and for multiple DNA barcode regions analyzed in this study was estimated using the Tree-Building and PWG-Distance methods. The usefulness of the DNA barcoding approach for analyzing and resolving taxonomic inconsistency among closely related and more phylogenetically distant conifers was evaluated and discussed.
The composition and variability of the terpenes and their derivatives isolated from the needles of a representative pool of 114 adult trees originating from four natural populations of dwarf mountain pine (Pinus mugo turra) from the Julian Alps were investigated by GC-FID and GC/MS analyses. In total, 54 of the 57 detected essential-oil components were identified. Among the different compound classes present in the essential oils, the chief constituents belonged to the monoterpenes, comprising an average content of 79.67% of the total oil composition (74.80% of monoterpene hydrocarbons and 4.87% of oxygenated monoterpenes). Sesquiterpenes were present in smaller amounts (average content of 19.02%), out of which 16.39% were sesquiterpene hydrocarbons and 2.62% oxygenated sesquiterpenes. The most abundant components in the needle essential oils were the monoterpenes δ-car-3-ene, β-phellandrene, α-pinene, β-myrcene, and β-pinene and the sesquiterpene β-caryophyllene. From the total data set of 57 detected compounds, 40 were selected for principal-component analysis (PCA), discriminant analysis (DA), and cluster analysis (CA). The overlap tendency of the four populations suggested by PCA, was as well observed by DA. CA also demonstrated similarity among the populations, which was the highest between Populations I and II.
The basic aim of the work was to widen the knowledge about variation of Pinus mugo in the Karkonosze (Giant) Mountains and verification of provenance of several, probably planted populations on that basis. Seven populations were sampled, four on hardly accessible precipices of glacial cirques as natural, and three on the topical, mostly plane or only slightly inclined parts of the mountains as potentially alien ones. The variation of the needles was biometrically analyzed in respect of 23 morphological and anatomical characters. Measurement data were subject of multivariate statistical analyses. Results call attention on rather continuous variability of P. mugo in the Karkonosze Mts. The differences among samples were found as relatively low and no direct connections have been detected between variation and provenance from precipices versus plane sites.
The results of morphological and anatomical studies on Pinus uliginosa needles from newly-discovered localities of this species in We{ogonek}glowiec (Bory Dolnośla{ogonek}skie) are presented. The data obtained were compared to similar published material on P. uliginosa needles from its loco classico in Batorów and from the lowland locality in We{ogonek}gliniec Nature Reserve, and to P. sylvestris growing nearby. In terms of needle structure, all three P. uliginosa populations were slightly different. The samples analyzed differed markedly from the sample of P. sylvestris, which contradicts the hypothesis that Scots pine has had a significant influence on the gene pool of P. uliginosa.
Headspace solid-phase microextraction (HS-SPME) coupled to GC/MS analysis was used to identify the constituents of pine-needle volatiles differentiating three closely-related pine species within the Pinus mugo complex, i.e., P. uncinata Ramond ex DC., P. uliginosa G.E.Neumann ex Wimm., and P. mugo Turra. Moreover, chemosystematic markers were proposed for the three analyzed pine species. The major constituents of the pine-needle volatiles were α-pinene (28.4%) and bornyl acetate (10.8%) for P. uncinata, δ-car-3-ene (21.5%) and α-pinene (16.1%) for P. uliginosa, and α-pinene (20%) and δ-car-3-ene (18.1%) for P. mugo. This study is the first report on the application of the composition of pine-needle volatiles for the reliable identification of closely-related pine species within the Pinus mugo complex.
Copyright © 2015 Verlag Helvetica Chimica Acta AG, Zürich.
The phenotypic differentiation of relic P. sylvestris in southern Europe and southwestern Asia was verified using thirty-two populations sampled from the Iberian Peninsula, Massif Central, Balkan Peninsula, Crimea and Anatolia. Twenty-one morphological and anatomical needle traits and 18 cone morphological characteristics were examined to describe the population diversity and differentiation. The needle characters were not correlated to those of cone. The differences between regions were significant based on 12 needle and 9 cone characteristics, suggesting spatial isolation. The differentiation between the Iberian and Anatolian populations was the highest, which indicates the isolation by distance. The high level of morphological differentiation was also found among Iberian populations, supporting the already known complex history of the species in that region. Populations within other regions were differentiated at lower levels; however, the West Anatolian populations differed morphologically from the eastern ones. The described pattern of morphological differentiation supports the idea of the long-lasting existence of P. sylvestris in the south-European and Anatolian mountain regions. To conserve this variation, seed transfer between regions in the forest economy should be restricted.
This work provides a tool whereby the needle remains of native, south-western European Pinus spp. can be easily identified from species-specific epidermal features. To construct this tool, the needles of P. uncinata, P. sylvestris, P. nigra, P. pinaster, P. pinea and P. halepensis were gathered across the Northern Hemisphere range of each taxon and compared with non-indigenous trees growing in two South Australian Botanic Gardens. Three needles from each of these species were taken from three adult trees growing at three different localities. Light microscopy was used to observe the key epidermal and stomatal features of the needles. To improve interpretation, additional scanning electron microscopy samples were prepared. Epidermal features, including variation in the diameter of the epistomatal chamber aperture (pore), are described. A taxonomic key based on the size, shape and arrangement of the subsidiary cells of the stomatal complexes was constructed. This key enables the identification of pine needle fragments at the species level (except those belonging to the group P. gr. nigra-uncinata). Despite their overlapping range, pore size was helpful in distinguishing between P. nigra and P. uncinata and between three groups of species. Isolated stomata were also observed. Cluster and discriminant analyses of stomatal variables described in
earlier studies were performed. Overlap in guard cell variables hampers species-level identification of isolated stomata. Species discrimination is improved if groups of ecological affinity are considered.
The aim of this study was to elucidate the introduction history of P. mugo in the unique landscape of the Lithuanian seaside spit of Kursiu Nerija by assessing its genetic structure and the genetic diversity. The individuals were sampled in 12 populations within an area of 3 km × 50 km along the Lithuanian part of Kursiu Nerija. P. mugo was introduced over 200 years ago to prevent sand erosion by establishing a forest cover. Chloroplast DNA polymorphism of 220 individuals of P. mugo together with 18 P. sylvestris and 11 putative P. sylvestris × P. mugo hybrids was assessed by the aid of five microsatellite markers. The standard intra-population diversity indexes were calculated. The intra-specific variation between distinct morphotypes as well as the population differentiation within the most spread P. mugo ssp. rotundata morphotype was assessed based on the haplotype frequencies by hierarchical AMOVA, GST/RST test, UPGMA clustering and PCA methods. The genetic diversity of P. mugo in Kursiu Nerija was high (He = 0.95; 83 different haplotypes). All except one of the P. mugo populations sampled contained a notable share of private haplotypes. AMOVA revealed high intra-specific diversity but low differentiation between the P. mugo populations. Most of the haplotypic variance was within populations. The UPGMA clustering produced groups more corresponding to the sub-species morphotypes than the geography of the populations. There was no geographical pattern of reduction in genetic diversity towards the younger plantations. A strong candidate for a species-specific DNA marker was found. After several events of introduction, the genetic diversity of P. mugo in Kursiu Nerija is very high and is structured based on the sub-species morphotypes rather than geography. The high frequency of shared and notable frequency of private haplotypes in most of the populations indicate that the major part of the P. mugo material originates from a number of geographically and genetically related sources, which more likely are introductions from abroad that the local collections. The high frequency of private haplotypes in the northernmost populations leaves a possibility for minor introductions from other genetically distinct sources. The absence of private haplotypes in one of the sampled populations indicates the use of local seed collections. The large number of shared haplotypes provides a strong evidence for a geneflow among the P. mugo taxa.
The main aim of the present study was testing
the value of the morphological and anatomical characteristics
of the needles in distinguishing Cedrus atlantica,
C. libani and C. brevifolia. Nine populations were sampled in
their natural habit and 25 characters were used to describe
the variation of the brachyblast needles and to analyze the
differences between species. The results indicated that
morphological and anatomical needle characters provide
valuable tools in discrimination of the taxa. The scored
differences were statistically significant, as revealed in the
Tukey’s t test, discrimination analysis and hierarchical
analysis of variation. The results support treating C. libani,
C. atlantica and C. brevifolia as independent species.
The genetic variation within and between 13 populations (385 individuals) of Pinus uncinata was analyzed with ten chloroplast microsatellite markers. Both the infinite allele mutation and stepwise mutation model (SMM)
have been applied to the analysis of the genetic structure and the geographical distribution of haplotypic variation. High
level of genetic diversity and low but significant differentiation among compared population were found. Three marginal populations,
Sierra de Cebollera, Margaride Mountains and Sierra de Gúdar are strongly differentiated from the rest. Mutations following
SMM-like process contributed significantly to the regional differentiation. The pattern of genetic structure observed in mountain
pine is common in conifers with a wide distribution range. Lack of significant genetic structuring may be a result of a recent
fragmentation of a historically larger population and/or interspecific hybridization and introgression. The southernmost populations
from the Sierra Cebollera and the Sierra de Gúdar are the most genetically distinct. This suggests a long period of spatial
isolation and/or origin from different ancestral populations.
Differences in morphological and anatomical characters of needles between seedlings, saplings and adult trees of the endangered Pinus uliginosa from the Węgliniec Nature Reserve in SW Poland were examined biometrically and statistically assessed using the Student's t-test, Tukey–Kramer test, step-wise discrimination and agglomeration on Euclidean distances according to Ward's method. Pinus sylvestris adults and seedlings were used as comparative material. The results show that needles of all three P. uliginosa generations differ significantly from each other. In seedling needles, several anatomical characters were similar to those of P. sylvestris growing in the vicinity of the reserve. However, P. uliginosa had a lower number of resin canals, lower frequency of fibre-like sclerenchyma cells and higher frequency of thin-walled sclerenchyma cells with large lumens in the spaces between vascular bundles. Needle characters of saplings and adult trees of both species were distinctly more different than it was the case in the seedling stage.
Nucleotide polymorphisms at genomic regions including 17 nuclear loci, two chloroplast and one mitochondrial DNA fragments were used to study the speciation history of three pine species: dwarf mountain pine (Pinus mugo), peat-bog pine (P. uliginosa) and Scots pine (P. sylvestris). We set out to investigate three specific speciation scenarios: (I) P. uliginosa is a homoploid hybrid between the other two, (II) the species have evolved without gene flow after divergence and (III) there has been substantial gene flow between the species since their divergence. Overall, the genetic data suggest that P. mugo and P. uliginosa share the same gene pool (average net divergence of 0.0001) and that the phenotypic differences (e.g. growth form) are most likely due to very limited areas of the genome. P. mugo and P. uliginosa are more diverged from P. sylvestris than from each other (average net divergence of 0.0027 and 0.0026, respectively). The nucleotide patterns can best be explained by the divergence with migration speciation scenario, although the hybrid speciation scenario with small genomic contribution from P. sylvestris cannot be completely ruled out. We suggest that the large amount of shared polymorphisms between the pine taxa and the lack of monophyly at all loci studied between P. sylvestris and P. mugo-P. uliginosa can largely be explained by relatively recent speciation history and large effective population sizes but also by interspecific gene flow. These closely related pine taxa form an excellent system for searching for loci involved in adaptive variation as they are differentiated in phenotype and ecology but have very similar genetic background.
Results of artificial fertilization of P. uliginosa with P. sylvestris and P. mugo are presented and discussed. P. sylvestris and P. mugo are thought to be the parental species of P. uliginosa. Two grafts of one P. uliginosa clone from Arboretum of the Institute of Dendrology in Kórnik, Poland were used as mother individuals. One individual of P. sylvestris and one individual of P. mugo were the pollen donors. Three mature cones were obtained as the result of artificial pollination of P. uliginosa with P. mugo pollen. Out of 107 seeds, 68 were filled what gives 63%. P. uliginosa conelets pollinated with P. sylvestris pollen were all aborted. Based on obtained data, close phylogenetic relationship between P. uliginosa and P. mugo complex is suggested.
By means of serological methods (double immunodiffusion, immunoabsortion and quantitative immunoprecipitation), using three kinds of antisera: antisylvestris, antimugo and antiuliginosa authors performed a comparison of antigenic properties of proteins from needles of P. sylvestris, P. mugo, P. uliginosa and P. nigra. Proteins characteristic for the species P. sylvesiris, and P. uliginosa were found. On the basis of the results obtained it was established, that the most distinct species are P. mugo and P. sylvestris, P. uliginosa is antigenically different from the two taxa but is showing greater similarity to P. mugo than to P. sylvestris. P. nigra proteins are different from proteins P. sylvestris, P. mugo, and P. uliginosa. They show however, some antigenic similarity to P. sylvestris proteins.
The frequency of occurrence of abnormal, three- (or more) needle dwarf shoots of most southern and central European two-needle pine (Pinus) species were studied. No specimens with more than two-needle dwarf shoots were found in a population of P. nigra Arnold subsp. salzmannii (Dunal) Franco from the Iberian Peninsula and in two populations of P. uliginosa Neumann from the Sudeten Mountains in Central Europe. Single specimens were found within one population of P. pinaster Aiton from the Iberian Peninsula and among six populations of P. sylvestris L. from the Iberian Peninsula and Central Europe. Abnormal dwarf shoots mostly with three, but also four, five or six needles were found among 24 of 25 surveyed populations of P. mugo Turra and P. uncinata Ramond. The average frequency of specimens with at least one three-needle dwarf shoot was 24% for P. mugo and 20% for P. uncinara. The frequencies of occurrence varied significantly among studied populations and were highest in samples collected from the upper elevational range limits of the species in the mountains and near the northern limits of their ranges. The frequency of abnormal dwarf shoots in the same populations was significantly high in 2-3 consecutive years. Needles from three-needle dwarf shoots were not significantly shorter than those of two-needle shoots.
Genetic structure of Pinus uliginosa Neumann from Wielkie Tor-fowisko Batorowskie peat-bog (locus classicus) was studied by means of isoenzyme variability and compared with genetic structure of P. mugo Turra from Tatra Mts and P. sylvestris populations from Klodzka Valley and Czersk. The level of genetic variability in the population of P. uliginosa (heterozygosity, genotypic polymorphism) was similar to that in populations of P. mugo, with an excess of homozygosity in relation to Hardy-Weinberg equilibrium. An average number of alleles per locus in population of P. uliginosa is the same as in the studied P. sylvestris populations, but the average number of genotypes is slightly lower. However, populations of P. mugo from montaneus stands in Tatra Mts. are characterized by a higher number of alleles per locus than that in P. uliginosa population.In populations of P. mugo from peat-bogs, a lower number of alleles and genotypes is noted than in P. uliginosa population. The coefficients of genetic similarity (Nei and Hedrick) show the distinctly separate character of P. uliginosa as compared to P. sylvestris and loose relationship of this taxon to P. mugo. Also the measure of genetic differentiation of populations (GST) confirms the specificity of this pine taxon.
Studies on taxonomic position of Pinus uliginosa Neumann, P. uncinata Ram. and P. mugo Turra, indicate a significant specificity of P. uliginosa population from Wielkie Torfowisko Batorowskie Peat Bog. Pinus uncinata in respect of genetic similarity is close to Pinus mugo Turra populations from the Tatra Mts. The time of divergence of P. uliginosa from the common ancestor, taking into account Nei's genetic distances, is twice as long as in the case of Pinus uncinata. In the view of the results the supposition that Pinus uliginosa from Wielkie Torfowisko Batorowskie Peat Bog is a marginal population of P. uncinata can be excluded, because of their significant difference in genetic structure. The presumable reasons of specificity of P. uliginosa population are disscused.
Peat-bog pine Pinus uliginosa Neumann has become extinct or rare in many parts of Europe. We have investigated the levels of genetic variation and inbreeding in seeds collected from a highly endangered reserve of this species in Poland, using allozymes as genetic markers. Generally, a high level of genetic variation was observed. The mean expected heterozygosity was 0.376, while average (Na) and effective (Ne) numbers of alleles per locus were 2.45 and 1.67, respectively. Nevertheless, we have detected relatively low levels of outcrossing, and potential biparental inbreeding. The population-wide multilocus outcrossing rate was estimated to be 0.706 (±0.091), while the minimum variance mean of single-locus estimates was distinctly lower (t s=0.611). The estimates of outcrossing calculated for individual trees ranged widely from 0.051 to 1.017, indicating the complexity of outcrossing patterns. The investigated population of P. uliginasa from Wȩgliniec is small and surrounded by extensive forest stands of P. sylvestris. Our three-year records of phenological observations demonstrated that flowering periods for P. uliginosa and P. sylvestris overlap, allowing for cross-pollination. The possibility of P. uliginosa pollination by P. sylvestris creates a potential danger of genetic erosion of the P. uliginosa gene pool. Nonetheless, based on a species specific cpDNA marker we have found that among 533 seedlings of P. uliginosa there were only six seedlings carrying cpDNA marker specific for P. sylvestris, indicating that such hybridization seems to be rare.
The characteristic of Pinus uncinata on the basis of biometrical analyses of 16 cone features was
done. The research was based on 8 samples representing 6 populations, consisting of 50 cones each, collected in the Pyrenees, within the natural range of the species. All the investigated cone features were moderately differentiated, with the variation coefficient ranging from 8 to 30%. The particular populations differ significantly from each other statistically according to several features examined. The samples collected in the same population also vary significantly. The differences between populations, however, do not enable their division into groups, which supports their origination from the same Pleistocene refugia.
Thirty-three individuals of Pinus mugo from the Abruzzian Apennines (Italy), the most isolated population of the species, were examined biometrically to verify the range of trait variation and compared with six other populations sampled in the north-eastern part of the species range. Ten needles and ten cones from each individual were measured and quantified on the basis of 31 traits. The interpopulation comparison revealed a close affinity of the Abruzzian population of P. mugo to three of the six other populations. The other three north-eastern populations, one from the Tatra Mountains and two from the Chornokhora Mountains, appeared to be different. This suggests that these populations originated from other Pleistocene centres of occurrence. The intrapopulation variation of the population from the Abruzzian Apennines is comparable with those of all six populations of P. mugo from the Sudety and Carpathian Mountains. These findings support the hypothesis that isolated but locally abundant plant populations do not necessarily show a reduction in variability resulting from isolation. © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society, 2005, 147, 309–316.
Eight natural populations of Pinus uncinata Ramond from the Spanish Pyrenees, five of P. mugo Turra from the Carpathians, the Sudethians and Abruzzian Apennines, three of P. sylvestris L. from the Central-European Lowland and the Iberian Peninsula and one of P. uliginosa Neumann from SW Poland have been compared biometrically in 16 cone characters. P. uncinata appears the most distant from all other taxa, differing by having the largest and most asymmetric cones and the thickest
apophyses with the most prominent umbo. In cone characters, P. mugo is more similar to P. sylvestris than to P. uncinata. Nevertheless, P. mugo and P. sylvestris remain distant from each other in a number of morphological characters examined. P. uliginosa has cones intermediate between the other three taxa and is moreover very variable. The locality of P. uliginosa in the Silesian Lowland may be of a relict character and conserve genes from P. uncinata.
In eight natural European populations of four closely related taxa of pines (Pinus sylvestris, P. mugo, P. uncinata, andP. uliginosa) starch-gel electrophoreses revealed altogether 58 alleles at 15 loci from nine enzyme systems. With Nei's genetic distance (D) the largest mean genetic distance (D = 0.171) was found betweenP. sylvestris andP. mugo, a distance corresponding to that between other closely related pine species. Mean genetic distances between the other taxa were less than half that value and characteristic for subspecies or varieties rather than for species. On the basis of our results we suggest that both,P. uliginosa andP. uncinata, could be the result of the ancient hybridization betweenP. sylvestris andP. mugo.
Two-year needles were collected from 42 trees from 5 localities in Spanish Pyrenees. The needles were analysed in respect to 15 morphological and anatomical traits. Data obtained were subject of multivariate statistical analyses. The most stable traits appear to be width of epidermis cells, width and thickness of the needles and ratio of the last two characters. Number of the resin canals and the vascular bundles distance were the most variable characters. The differences among the 42 investigated trees are not evident, considerably small and not significant statistically.
Artificial hybridization experiments revealed a relatively high degree of crossability between Pinus sylvestris and P. mugo, ranging between 0.15 and 0.98. Differences between P. sylvestris x P. mugo and reciprocal hybrids of the species were observed. Hybrid seeds of P. sylvestris x P. mugo shared higher germination potential than seeds from selfing, controlled intraspecific crossing, and open pollination. The corresponding value in reciprocal combination was slightly lower. The hybrid nature of the seeds obtained was shown by restriction analysis of chloroplast DNA (cpDNA) using the trnV-trnH/Hinf I primer-enzyme combination.
Hybridization between Pinus mugo and P. sylvestris (Pinaceae) is visualized in Wells' distances diagrams and plots of Common Principal Components Analysis (CPCA or PCA). These serve as an example to demonstrate the effects of character weighting in hybrid analysis. Estabrook's HYWIN program is also used as a test of the hypothesis of hybridity of putative hybrids. Parents and hybrids are apparently better resolved when using differently weighted characters.
Questo lavoro consiste in un'analisi biometrica di alcuni caratteri morfoanatomici dellla foglia in un campione di individui sufficientemente rappresentativo di Pinus mugo agg. in Trentino. Per mezzo di questi caratteri è stata valutata la similarirà tra gli individui e contemporaneamente il campione del Trentino è stato confrontato con due campioni di riferimento proposti da SANDOZ (1987) per Pinus mugo s. str. e per Pinus uncinata. L'analisi mostra che gli individui del Trentino appartengono chiaramente a due gruppi: il primo che contiene individui del Trentino settentrionale, affine a Pinus mugo s. str. e il secondo, che invece contiene individui provenienti dal settore meridionale della regione, affina a Pinus uncinata. Si è cercato inoltre di mettere in relazione i caratteri morfoanatomici della foglia con un altro carattere classicamente usato per distinguere Pinus mugo s. str. da Pinus uncinata, cioè il portamento. Il portamento arbustivo, carattere proprio di Pinus mugo s. str., è comune a tutti gli individui del Trentino di conseguenza gli individui del settore settentrionale della regione presentano tutti i caratteri (caratteri morfoanatomici della foglia e portamento) tipici di Pinus mugo s. str., mentre nel Trentino meridionale gli individui studiati presentano alcuni caratteri di Pinus uncinata (caratteri morfoanatomici della foglia) ed altri propri di Pinus mugo s. str. (portamento).
Seven populations of Scots pine (Pinus sylvestris L.) from the natural distribution of the species in Spain were investigated isoenzymatically at 11 enzyme loci, and compared with 16 populations from northern and eastern Europe at seven loci. Populations from Spain are genetically differentiated in relation to the frequencies of genes and genotypes. The similarity between the 7 populations was studied and agreed to a significant extent with taxonomical subdivisions of Scots pine on the Iberian peninsula. The Spanish and the northern and eastern European populations form 2 very distinct and heterogeneous groups according to the genetic similarity. In comparison with the other European populations the Spanish material showed a slightly higher number of alleles per gene locus, a higher number of genotypes, and a slightly lower degree of heterozygosity. In the Spanish populations five were detected, which are not present in the other European populations, whereas in the northern and eastern European populations only 2 alleles were found, which were not present in the Spanish material.
Natural hybridisation between the taxa from Pinus mugo complex and P. sylvestris was postulated in several sympatric populations of the species in Europe. However, due to the absence of precise methods for identification of hybrid seeds and hybrid trees, the frequency of hybridisation and its influence on the genetic structure of relict P. mugo populations has not been clarified so far. In the present study, the species-specific chloroplast DNA (cpDNA) marker and isozymes were applied to test the hybridisation hypothesis in a postulated hybrid swarm population of the species from “Bór na Czerwonem” reserve at the northern foothills of Tatra Mts., Poland. The cpDNA marker was used to identify hybrids within two groups of polycormic (multi-stemmed) and monocormic (single-stemmed) pines from this population. Allelic frequencies at isozyme loci from both groups were compared to frequencies found in allopatric populations of the species. Additionally, cpDNA haplotypes of seedlings derived from open pollinated seeds were studied to detect the possibility of successful cross-pollination. The mixture of seedlings with P. sylvestris and P. mugo cpDNA haplotypes was derived from one parental tree that indicates hybridisation. However, all the mature polycormic pines had cpDNA haplotypes species specific to P. mugo and the isozyme frequencies were similar to frequencies found in three allopatric populations of P. mugo from Tatra Mts. (mean genetic distance, Dn=.027). The differences were much larger in comparisons with monocormic pines from this area (Dn=.085) and two P. sylvestris samples from distant allopatric populations (Dn=.077). Nearly all monocormic pines had cpDNA species specific to P. sylvestris and isozyme frequencies similar to other populations of this species (mean Dn=.004). Only one P. sylvestris-like monocormic tree had cpDNA of P. mugo and can be considered as a hybrid. The results do not provide evidence supporting the hybrid swarm hypothesis. Rather, the results suggest that mature hybrids have a low frequency within this population and (rare) hybridisation is not reciprocal but unidirectional with P. mugo as pollen donor.
The assembly of Mediterranean pines in the sense ofMirov is inhomogeneous in respect to morphological, geographical and evolutionary affinities. Considering new or neglected characters (vegetative and particularly reproductive, cone scales, apophyses, mucros, seeds: Figs. 1–3) in extant populations and fossils, three groups are recognized. The group of coast and island pines extends from the Canary islands to the Himalaya region and is closely related to Caribbean and C. American taxa. This complex evidently has originated from haploxyl ancestors of sect.Parrya during the Mesozoic (Upper Jurassic/Lower Cretaceous) in the NW. Tethys area (Fig. 13).P. rzedowskii can be regarded as an extant survivor of this first phase of differentiation. The extremely variableP. canariensis (together withP. roxburghii in sect.Sula) marks a transitional phase towards the more advanced diploxyl species of sect.Pinea (withP. pinea, P. halepensis &P. brutia, and subsect.Oocarpae) and sect.Pinaster (withP. pinaster, etc.) (Figs. 4–12).—The second group consists of diploxyl mountain pines from the areas surrounding the Mediterranean. They are classified as members of the Eurasiatic sect.Pinus subsect.Sylvestres, have differentiated along the northern Parathetys area, and exhibit close links with E. Asiatic taxa. The third group includes the haploxyl mountain pinesP. cembra andP. peuce which can be regarded as western outposts of the circumpacific centred sect.Strobus with a pre-Tertiary origin.—As an appendix, an improved classification scheme is presented for the pine groups discussed.
Phenological observations of development of generative organs of Pinus sylvestris and P. uliginosa (= P. rotundata) were carried out in spring of 1999, 2000 and 2001. The aim of the research was to verify the hypothesis that both taxa have a possibility of reciprocal crossing. Two populations of P. uliginosa were tested, one on the Silesian Lowland (Węgliniec) (altitude of 180m), the other in the Stołowe mountains (Batorów) (at altitude of 750 m). The lowland population of P. uliginosa is not numerous and surrounded by extensive P. sylvestris forests, the mountain one is 3 times more numerous, and the nearest population of P.sylvestris is at a distance of 2 km. Observations in the field were carried out twice a week during the period of development of micro- and macro-strobili of both taxa. The results show that the P. sylvestris strobili developed every year earlier than those of P. uliginosa. Nevertheless, this did not eliminate the possibility of cross pollination and gene flow from P. sylvestris toward P. uliginosa on both localities of the last species. The possibility of pollination of P. sylvestris macrostrobili by P. uliginosa pollen was found also possible, but more restricted. Normally, on lowlands the same phenological phases take place about 10 days earlier than in the mountains. This is documented for two years of observations of more or less typical whether conditions. An earlier development of micro- and macrostrobili of both species in their mountain populations was observed in an observation year characterized by an extremely early and warm spring.
The flavonic profile of Peatbog pines Pinus uliginosa Neumann from Poland and France (with low quercetin content) are close to that of Mugo pine P. mugo Turr. and Mountain pine P. uncinata Ram.; in this respect, the two latter species are indistinguishable. However, the presence of some individuals of sylvestris type (with high quercetin content) is notable; moreover, trees with intermediate quercetin contents can be numerous, revealing a hybridization process in good accordance with Hardy-Weinberg's rule. Foliar morphometry (fineness index: L/P) tends toward the uncinata/mugo type. If specific status is to be conferred to Peatbog pine, it should be admitted that it results from the persistance in this biotope of past crossbreeding between Mountain/Mugo pine and Scots pine (more precisely its chemomorph T-, taxifolin absent), with the second taxon subordinated to the first. A comparison is made with current hybridization and introgression processes at high altitudes, which lead to the Bouget pine Pinus bougeti Flous from the same parent species.
«Pinus mugo» Turra and «Pinus uncinata» Miller in Piedmont. Critical notes and distribution. — The Authors have carried on a research on the distribution of Pinus mugo Turra (sensu Fl. Eur.) and Pinus uncinata Miller in all Piedmont Alpes and, having observed the extreme variability of the characters which are employed in the keys of determination to differentiate these two species, they suggest other and more constant characters. These are:Pinus uncinataPinus mugoLeaves dark green, sometimes with silvery hues, generally long.Leaves yellow green, generally short.Leaves uniformly covering apical ends of branches.Leaves on the terminal part of branches verticillate.Branch apex apparently rounded owing to uniform development of leaves.Branch apex apparently truncate owing to reduced development of apical leaves.Young plants clearly showing a main stem scarcely branched.Young plants abundantly branched from their basis; sometimes 2–3 separate sterns emerging from ground.Resination abundant.Resination scanty.They have also considered the istological features, which are found to show complete and gradual transition from Pinus sylvestris L. to Pinus uncinata and to Pinus mugo. As these species show a great tendency to hybridate, the authors suggest the hypothesis that Pinus uncinata, with western area, may be an ancient hybrid between Pinus sylvestris and Pinus mugo, with eastern area. In suppor of this hypothesis, as well as the gradual transition of leaf characters, they can take ecological and palinological data.
Eleven needle traits of two contrasting populations of Pinus uliginosa (P. mugo complex), one located in a Pinus sylvestris forest, the other isolated from the influence of this species, were compared to quantify the degree of hybridization. Statistically significant differences between the studied populations were found, but both of them differed by a similar degree from P. sylvestris. Surprisingly, the P. uliginosa population surrounded by the P. sylvestris forest, which was expected to consist of individuals with intermediate traits, appeared to be more closely related to P. mugo than those isolated from the direct influence of P. sylvestris. Large differences in the distances between the analysed pair of populations of P. uliginosa and P. sylvestris have not influenced the morphological traits of the species. Gene flow from P. sylvestris to P. uliginosa is possible, but is likely to be small and does not differ compared with populations of P. uliginosa. The decline observed during the last three decades in both populations of the species has not influenced their needle morphological traits. © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 142, 83–91.
Pinus sylvestris and P. mugo populations from Poland and Czechoslovakia were compared using genetic variability at isozyme markers, chloroplast DNA variation, and mating system measurements. Two isozyme loci were found to differ between the species. P. mugo was as variable at isozyme loci as P. sylvestris. Diagnostic cpDNA fragments were found using the restriction enzyme Bcl-I. Populations that were morphologically classified as hybrids were found to be pure species, based both on isozyme and cpDNA results.
Local and geographical variation in the Pinus mugo Turra complex, and the degree and effects of natural hybridization between P. mugo Turra and P. sylvestris L. are studied using various multivariate techniques. Reciprocal introgressive hybridization between the eastern P. mugo ssp. mugo and the western ssp. uncinata (Ram.) Domin has resulted in a topoclinal east-west variation in the complex. The frequency and significance of hybridization and introgression between P. mugo and P. sylvestris is apparently low.
Unter Einsatz verschiedenartiger Techniken wurden die lokale und geographische Variation im Pinus mugo Turra Komplex und der Grad und die Folgen natürlicher Hybridisation zwischen P. mugo und P. sylvestris studiert. Reziproke introgressive Hybridisation zwischen dem östlichen P. mugo ssp. mugo und der westlichen ssp. uncinata (Ram.) Domin führte zu einer topoklinalen Ost-West-Variation dieses Komplexes. Häufigkeit und Bedeutung von Hybridisation und Introgression zwischen P. mugo und P. sylvestris sind bemerkenswert niedrig.
Peat-bog pine Pinus uliginosa Neumann has become extinct or rare in many parts of Europe. It is supposed to hybridize with P. sylvestris but the influence of hybridization to genetic erosion of the P. uliginosa gene pool is unknown. In the presented study, the crossability between P. uliginosa and P. sylvestris was analyzed in a sympatric population at Węgliniec reserve in Poland. The aim of the study was to prove natural hybridisation and to estimate the influence of this phenomenon on possible natural gene pool erosion of peat-bog pine. A sequence polymorphism in the trnF–trnL cpDNA region of P. uliginosa and P. sylvestris was used to develop the species diagnostic PCR-RFLP marker. The marker of paternally transmitted cpDNA was applied in haplotype analyses of the progeny from open-pollinated P. uliginosa seeds (collected in 2000–2002) and from P. sylvestris ones (in 2002). An inconsistency in species diagnostic cpDNA haplotypes of seedlings and parental trees was observable both for P. uliginosa and P. sylvestris (about 1% and 2% of hybrids seeds, respectively). The results prove the occurrence of reciprocal hybridisation between the species. The influence of hybridisation on the natural gene pool protection and measures to reintroduce peat-bog pine is discussed.
Hybridization among Pinus mugo and P.sylvestris is visualized in Wells' distance diagrams using either equally or differently weighted characters. Parents and hybrids are better resolved in diagrams using differently weighted characters. Putative hybrids from mixed, planted or naturalized stands of P. mugo and P. sylvestris in SW and NW Jutland, Denmark, are compared with artificial F1 and spontaneous material of P. mugo × sylvestris (P. × rhaetica) from the Alps and the Pyrenees. The natural hybrids are primary hybrids, rather than introgressants.
The Pinus mugo complex is revised, and a new infraspecific classification of the species is proposed. The species is divided into two subspecies and an intermediate nothossp., viz. ssp. mugo, ssp. uncinata and nothossp. rotundata. P. mugo ssp. mugo is divided into f. mugo and f. applanata comb, et stat. nov. (P. pumilio) and P. mugo nothossp. rotundata into f. rotundata and f, mughioides comb. nov. The putative hybrid P. mugo × sylvestris found in mixed stands of the parents is named P. × rhaetica. A description of P. sylvestris and a key to P. mugo, P. sylvestris and P. × rhaetica is given.
Former controlled crosses between twelve Pinus montana var. rostrata (Pinus mugo complex) and eight P. sylvestris clones revealed that only two P. sylvestris had efficiently fertilised P. montana. Two species-diagnostic chloroplast DNA markers were applied to verify the species purity of the parental clones. All maternal
P. montana were unambiguously confirmed to belong to the P. mugo complex at both chloroplast DNA marker loci. Six P. sylvestris clones carried the `sylvestris' haplotypes. However, the same two P. sylvestris clones that had efficiently fertilised P. montana displayed the chloroplast haplotypes diagnostic to the P. mugo complex. The patterns of highly polymorphic cpDNA microsatellite markers in parents and offspring ruled out contamination
by foreign pollen. We concluded that the two clones successful in the crosses represent fertile hybrids between the two species
with P. mugo as the pollen donor. Consequently, DNA markers are proposed for verifying or falsifying the success of artificial fertilisation
in general. The existence of crossing barriers between the two Pinus species, meaningful to the postulated natural hybridisation and the evolution of their populations in sympatric stands, was
indicated and is newly discussed.
The description of bud development presented here is based primarily on the findings of Hejnowicz and Obarska (1995) and related studies. The embryonic shoots of vegetative and reproductive buds are visibly easy to differentiate in
winter. With the aid of a microscope, it is possible to differentiate between bud types some months earlier. For example,
in Poland the differentiation of the bud type takes place sometime in June (unpublished data; Fig. 6.1).
11 needle characters of Pinus uncinata Ramond from the Spanish Pyrenees, P. mugo Turra from the Tatra Mountains, and P. sylvestris L. from N.E. Poland were analysed. It was shown that P. uncinata is much more closely related to P. mugo than to P. sylvestris. Nevertheless P. uncinata remains distinct from both in a number of the characters examined. The species differs from P. mugo especially in the length of the needles and in the distance between the vascular bundles. It differs from P. sylvestris in such characters as the number of resin canals, thickness of epidermis cells and the distance between the vascular bundles.
Width of epidermis cells was similar in all taxa studied.
Genetic structure and genetic diversity in fourteen autochthonous populations of Pinus sylvestris L. from the Iberian peninsula and two populations from the Massif Central in France were studied at eleven isoenzymatic polymorphic loci. The studied populations formed two genetically similar but heterogeneous groups. The first group consist of populations localized in North-Eastern Spain with two genetically distinct populations. The second includes populations of the West-Central part of the Iberian peninsula. Populations from the Massif Central in France are diverse from those of Spain, but are similar to the group from North- part of the Iberian peninsula. The existence of significant numbers of private alleles in Spanish populations which were not observed in populations from the Massif Central, suggests that the Scots pine from the Iberian peninsula probably did not take part in the colonization of Europe after the last glaciations and represents original ancient tertiary gene pools.