No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
Experimental studies of evolution in Anthoxanthum (Gramineae)
Abstract
Hybridization reveals the close affinity ofAnthoxanthum odoratum and the Mediterranean annualA. ovatum. A. alpinum is genetically somewhat more isolated; occasional sterile hybrids withA. ovatum can be obtained.
Morphology reveals an affinity betweenA. odoratum andA. ovatum. There are nodiagnostic characters linkingA. odoratum toA. alpinum.
The perennial nature of the generality ofA. odoratum, plus phenotypic flexibility and an ability to behave as an annual in particular habitats, suggest an affinity both toA. alpinum (winter-hardy perennial) andA. ovatum (variable annual or occasional biennial).
The artificial allotetraploid based on the sterile hybrid betweenA. alpinum andA. ovatum simulatesA. odoratum, more closely than do either of the diploids.
Experimental observations suggest a very reasonable possibility that a similar sequence of events perhaps occurring on several occasions under natural conditions could have given rise to the tetraploid speciesA. odoratum.
... Anthoxanthum L., the vernal grass, is a genus of the family Poaceae, comprising annual and perennial taxa that are often self-incompatible [1] and show large diversity in ploidy and morphology (e.g., [2,3]). Despite being a relatively small genus standing out of main research attention within the Poaceae, it offers a great opportunity to study different modes of polyploidization and their consequences for the further evolution of the entire genus. ...
... Mainly on the basis of genetic and phenotypic evidence Borrill [1] has concluded that A. odoratum could have arisen from the hybridization of A. alpinum and A. ovatum or their closely related ancestors. To verify Borrills' conclusions, Jones [14] did a chromosome study on A. odoratum. ...
... The hybridization pattern was highly variable between individual populations of A. odoratum, including numerous intergenomic translocations (Figure 7). GISH probe corresponding to A. alpinum (red fluorescence in Figure 7 and Figure S1) covered from 1 4 (PT09 and Norwegian NO01) up to 1 2 (in the Icelandic IS02) of the allopolyploid genome, i.e., 5-10 chromosomes were detected using gDNA of A. alpinum. The Mediterranean-like genome fraction (green fluorescence in Figure 7 and Figure S1) virtually forms from 1 2 to 3 4 of the hybrid genome (i.e., 10-15 chromosomes) regardless of which of the Mediterranean gDNA probe was used. ...
Polyploidy has played a crucial role in the evolution of many plant taxa, namely in higher latitudinal zones. Surprisingly, after several decades of an intensive research on polyploids, there are still common polyploid species whose evolutionary history is virtually unknown. Here, we addressed the origin of sweet vernal grass (Anthoxanthum odoratum) using flow cytometry, DNA sequencing, and in situ hybridization-based cytogenetic techniques. An allotetraploid and polytopic origin of the species has been verified. The chromosome study reveals an extensive variation between the European populations. In contrast, an autopolyploid origin of the rarer tetraploid vernal grass species, A. alpinum, has been corroborated. Diploid A. alpinum played an essential role in the polyploidization of both European tetraploids studied.
... Contradictory studies regarding morphological and karyological differences between the cytotypes and karyotypes (reviewed by Hedberg 1990) have led to disagreements on the taxonomic rank that should be applied to the ploidy levels. Tutin (1950), Rozmus (1958Rozmus ( , 1960, Borrill (1961Borrill ( , 1963, Jones and Melderis (1964), Mayová (1982), Felber (1986Felber ( , 1988Felber ( , 1993, and Lauber and Wagner (2001) considered the diploids and tetraploids to represent well-defined species that can be distinguished by certain morphological characters (Table 1), whereas Böcher (1961) and Hedberg (e.g., 1970Hedberg (e.g., , 1986Hedberg (e.g., , 1990 concluded that the specific rank is not justified for A. alpinum since rather high morphological variability can be observed in natural populations. ...
... Contradictory studies regarding morphological and karyological differences between the cytotypes and karyotypes (reviewed by Hedberg 1990) have led to disagreements on the taxonomic rank that should be applied to the ploidy levels. Tutin (1950), Rozmus (1958Rozmus ( , 1960, Borrill (1961Borrill ( , 1963, Jones and Melderis (1964), Mayová (1982), Felber (1986Felber ( , 1988Felber ( , 1993, and Lauber and Wagner (2001) considered the diploids and tetraploids to represent well-defined species that can be distinguished by certain morphological characters (Table 1), whereas Böcher (1961) and Hedberg (e.g., 1970Hedberg (e.g., , 1986Hedberg (e.g., , 1990 concluded that the specific rank is not justified for A. alpinum since rather high morphological variability can be observed in natural populations. ...
... For instance, the presence or absence of hairs on the lower glume, the latter considered diagnostic for A. alpinum (Knaben 1950;Tutin 1950;Jones and Melderis 1964;Lauber and Wagner 2001), was variable in some of the diploid populations studied, such as those at Nipfjället Mt. and Björkliden. This previously has been reported by Borrill (1963) and Hedberg (1964Hedberg ( , 1967 for populations in the British Isles, Scandinavia, and the Alps. ...
The genus Anthoxanthum s.l. (including Hierochloë) (Poaceae, Pooideae, Aveneae) comprises 35–50 species and has a cosmopolitan distribution. Anthoxanthum alpinum was described as a diploid perennial that is distributed in northern Eurasia and in the high mountains of central and eastern Europe. Difficulties in finding reliable morphological differences between this taxon and the widespread tetraploid A. odoratum have resulted in taxonomists treating them as conspecific, despite the cytological differentiation. The purpose of this study was to provide information that may help clarify the relationships between these taxa. Macromorphologial, micromorphological, and anatomical data were gathered and analyzed for 14 populations representing both taxa from Scandinavia and the Iberian Peninsula. Statistical analyses were carried out to identify the most useful characters for taxonomy. The relationships among samples were based on different similarity coefficients and summarized using UPGMA clustering methods. The results show that geography has more statistical weight than ploidy level in explaining the relatedness among individuals and populations. A strong correlation between leaf micromorphological/anatomical characters and environmental parameters was detected. The results of the analyses do not support recognition of A. alpinum as a distinct species.
... Karyologically, these species are similar, differing only in the frequency and location of secondary chromosome constrictions (Jones, 1964). As regards reproductive biology, A. ovatum is mostly self-incompatible (Borrill, 1963;Borrill & Carroll, 1965), as is the tetraploid A. odoratum L. (Wu & Jain, 1980) and the diploid A. alpinum Löve & Löve (Borrill, 1963). The breeding system of A. aristatum has not been analysed yet, but self-incompatibility is quite prevalent in the genus (Borrill, 1963). ...
... Karyologically, these species are similar, differing only in the frequency and location of secondary chromosome constrictions (Jones, 1964). As regards reproductive biology, A. ovatum is mostly self-incompatible (Borrill, 1963;Borrill & Carroll, 1965), as is the tetraploid A. odoratum L. (Wu & Jain, 1980) and the diploid A. alpinum Löve & Löve (Borrill, 1963). The breeding system of A. aristatum has not been analysed yet, but self-incompatibility is quite prevalent in the genus (Borrill, 1963). ...
... As regards reproductive biology, A. ovatum is mostly self-incompatible (Borrill, 1963;Borrill & Carroll, 1965), as is the tetraploid A. odoratum L. (Wu & Jain, 1980) and the diploid A. alpinum Löve & Löve (Borrill, 1963). The breeding system of A. aristatum has not been analysed yet, but self-incompatibility is quite prevalent in the genus (Borrill, 1963). Experimental studies have demonstrated that A. ovatum and A. aristatum can cross, although this process involved some loss of fertility (Borrill, 1963). ...
The morphologically diverse annual sweet vernal grasses, Anthoxanthum aristatum and Anthoxanthum ovatum, have been traditionally classified as separate species, each containing several infraspecific ranks. However, transitional forms between the species have been commonly found in sympatric populations that present a remarkably high morphological variability. Alternative hypotheses based on hybridization events between these two polymorphic Mediterranean species, or the existence of only one highly variable taxon, have been suggested as potential explanations for the presence of intermediate forms. In this study, we aimed at disentangling whether the integrity of the species is maintained in sympatric scenarios and at clarifying the taxonomic boundaries of the taxa described within this complex. For this, we analysed macro- and micromorphological and genetic data from 12 Iberian populations of A. aristatum and A. ovatum. Our results revealed the existence of two lineages in the A. aristatum/A. ovatum complex that were not consistent with the morphological circumscription of these species and suggested introgression between A. aristatum and A. ovatum. We also observed that morphological variability was not equally distributed between the lineages. Finally, we found some morphological and genetic support for the specific recognition of A. aristatum and A. ovatum, but the definition of any infraspecific category within these taxa does not seem to be justified. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 164, 53–71.
... This problem is present not only at the polyploid level, but even among diploids. For instance, the taxonomic as well as phylogenetic position of the 'Mediterranean diploid' among its counterparts is completely uncertain, in spite of long-standing awareness of its existence (Briquet, 1910;Borrill, 1963;Jones, 1964;Hedberg, 1967;Teppner, 1970;Felber, 1987;Chumov a et al., 2015). Another example is the occasional lumping of the phenotypically similar annuals A. aristatum and A. ovatum into the A. aristatum/ovatum complex based on genetic data (Pimentel et al., 2007b(Pimentel et al., , 2010, salient morphological resemblance (Pimentel and Sahuquillo, 2003;Pimentel et al., 2007aPimentel et al., , 2010 and indistinguishable but extremely variable genome size (Chumov a et al., 2015(Chumov a et al., , 2016. ...
... Clear separation from other diploid taxa and connection to some polyploids supplies the first evidence in the long-term debate about participation of A. alpinum in polyploid formation (e.g. Borrill, 1963;Jones, 1964;Teppner, 1970;Hedberg, 1986;Chumov a et al., 2015). Based on its linkage to at least some polyploid lineages we can conclude that A. alpinum played a substantial role in polyploid evolution. ...
Background and aims:
Knowledge of diploid phylogeny and ecogeography provide a foundation for understanding plant evolutionary history, diversification patterns and taxonomy. The genus Anthoxanthum (vernal grasses, Poaceae) represents a taxonomically intricate polyploid complex with large phenotypic variation and poorly resolved evolutionary relationships. The aims of the study were to reveal: (1) evolutionary lineages of the diploid taxa and their genetic differentiation; (2) the past distribution of the rediscovered 'Mediterranean diploid'; and (3) possible migration routes of diploids in the Mediterranean.
Methods:
A combined approach involving sequencing of two plastid regions ( trnL-trnF and rpl32-trnL ), nrDNA ITS, rDNA FISH analyses, climatic niche characterization and spatio-temporal modelling was used.
Key results:
Among the examined diploid species, only two well-differentiated evolutionary lineages were recognized: Anthoxanthum gracile and A. alpinum . The other taxa - A. aristatum, A. ovatum, A. maderense and the 'Mediterranean diploid' - form a rather intermixed group based on the examined molecular data. In situ rDNA localization enabled identification of the ancestral Anthoxanthum karyotype, shared by A. gracile and two taxa from the crown group. For the studied taxa, ancestral location probabilities for six discrete geographical regions in the Mediterranean were proposed and likely scenarios of gradual expansion from them were suggested. Modelling past and present distributions shows that the 'Mediterranean diploid' has already been occurring in the same localities for 120 000 years.
Conclusions:
Highly congruent results were obtained and dated the origin and first diversification of Anthoxanthum to the Miocene. The later divergence probably took place in the Pleistocene and started polyploid evolution within the genus. The most recent diversification event is still occurring, and incomplete lineage sorting prevents full diversification of taxa at the molecular level, despite clear separation based on climatic niches. The 'Mediterranean diploid' is hypothesized to be a possible relic of the most recent common ancestor of Anthoxanthum due to their sharing of ancestral features.
... Anthoxanthum odoratum is an allopolyploid, deriving from diploid ancestors whose genomes were similar to those of present-day A. ovatum and A. alpinum (Borrill 1963;Jones 1964). Cytological research aimed to assess the number of rDNA loci and DNA content in A. odoratum, has revealed complex rearrangements within the Anthoxanthum genome, consisting in deletion and insertion of DNA segments (Drapikowska et al. 2013). ...
... This is confirmed by morphological investigations (Drapikowska 2013) and the present study of isozymes. Crossing of these 2 taxa is difficult because of differences in their ploidy (Borrill 1963). Moreover, a comparative cytogenetic study has detected differences in genome size and number of rDNA loci between the 2 species, indicating substantial rearrangements within their genomes (Drapikowska et al. 2013). ...
Variation of 9 isozyme systems was studied in Polish populations of 3 species of the genus Anthoxanthum: the native A. odoratum s. str. L. and A. alpinum Á. Löve & D. Löve, as well as the alien A. aristatum Boiss. Results of this study show that A. odoratum is characterized by a high isozyme variability of lowland populations, weakly correlated with habitat type, and partial genetic distinctness of montane populations. Moreover, 5 isozyme markers have been identified (Pgi-2, Dia-2, Mdh, Idh, Pgm) for the allopolyploid A. odoratum. Populations of A. aristatum are highly polymorphic (P = 98%). The observed isozyme differentiation of its populations (FST = 0.087) is low and gene flow between them (Nm = 5.314) is high. The genetic variation reflects environmental variation only to a small extent and is not significantly related to the phase of chorological expansion of this species. Altitudinal vicariants, A. alpinum and A. odoratum, are characterized by morphological and isozymatic distinctness, indicating their reproductive isolation. In populations of A. alpinum, polymorphism is high (P = 76.92%), differentiation among populations is moderate (FST = 0.198), and gene flow between populations along the altitudinal transect (Nm = 1.709) is relatively low
... Clayton and Renvoize, 1986; Connor, 2008 Connor, , 2012 Edgar and Connor, 2010). Section Anthoxanthum comprises nine or ten annual and perennial taxa that often are self-incompatible (Borrill, 1963) and show large diversity in ploidy and morphology (e.g. Pimentel et al., 2007a;Table 1 ). ...
... Analysis of independent loci from different genomes (nuclear and plastid) has been advocated for studies of complex groups of taxa (Linder and Rieseberg, 2004; Havill et al., 2008 ) and is especially relevant for polyploid-rich lineages such as Anthoxanthum in which reticulate evolution may be common (e.g. Borrill, 1962 Borrill, , 1963 Felber-Girard et al., 1996; Pimentel and Sahuquillo, 2007b). The development of new Bayesian dating methods (e.g.) and recent studies on the divergence times of the grass subfamilies (Prasad et al., 2005; Strömberg, 2005; reviewed in Vicentini et al., 2008) have improved the possibility for reliable divergence dating in grasses. ...
Background and Aims Repeated hybridization and/or polyploidization confound classification and phylogenetic inference, and multiple colonizations
at different time scales complicate biogeographical reconstructions. This study investigates whether such processes can explain
long-term controversies in Anthoxanthum, and in particular its debated relationship to the genus Hierochloë, the evolution of its conspicuously diverse floral morphology, and the origins of its strikingly disjunct occurrences. A
hypothesis for recurrent polyploid formation is proposed.
... and Anthoxanthum ovatum Lag.). However, this distinction is rather unclear, since A. odoratum can behave as an annual, and biennial plants of A. aristatum and A. ovatum have been found (Borrill 1962;Hedberg 1964). The morphological differentiation of these taxa has been traditionally based on plant height and spikelet length, sterile floret shape, spike color, plant pubescence, and ligule type. ...
... ovatum complex should be considered different species (e.g., Paunero 1953;Tutin 1980). Then, the different ploidy level would reinforce the isolation of these taxa, although several hybridization experiments conducted have rendered viable offspring (Borrill 1962;Grosstête 1982). Nevertheless, to clarify this situation further research involving molecular analyses would be needed. ...
In the present study, several multivariate analyses were carried out to assess the taxonomic relationships among European species of the genus Anthoxanthum. A total of 1787 Anthoxanthum specimens representing all European taxa were analyzed. Thirty macro-morphological (13 quantitative and 17 qualitative) and 29 micro-morphological (7 quantitative and 22 qualitative) characters were considered. First, resemblances between specimens were established independently for macro- and micro-morphological characters using Gower's similarity coefficient, and were represented by means of principal coordinates and cluster analyses. Subsequently, different multivariate analyses were applied to quantitative and qualitative macromorphological data to determine the most discriminant characters and the accuracy of the present taxonomic structure of the genus. Finally, dissimilarities among groups of individuals –species and populations- were estimated using the information radius measure and then represented in different dendrograms. Within annuals, Anthoxanthum gracile is clearly differentiated morphologically, yet no compelling morphological differentiation can be found between Anthoxanthum aristatum and Anthoxanthum ovatum. Moreover, the definition of subspecies in the annual taxa is not supported by our results. Then, within perennials, although the morphological relationships among Anthoxanthum amarum, Anthoxanthum odoratum and Anthoxanthum alpinum have also been resolved, further research is needed to assess the taxonomic position of the Macaronesian endemic Anthoxanthum maderense.
... The species has a very wide edaphic tolerance (Kruijne and De Vries, 1963). It is morphologically quite variable, but is well defined taxonomically; it is almost completely self-incompatible (Borrill, 1963), though a small amount of self fertilization may occur (Antonovics, 1968). This series of investigations examines population differentiation in A. odoratum within the mosaic of contrasting soil environments of the Park Grass experiment; this paper deals specifically with the performance of populations, collected from contrasting contiguous plots, when grown on calcareous and acid soils. ...
... Anthoxanthum odoratum L., (hereafter, Anthoxanthum), a short-lived, highly variable (Borrill, 1963), perennial grass native to Eurasia and northern Africa, is widely distributed along the Pacific coast from northern California to British Columbia. Along the northern Pacific coast it is common along roadsides, in waste places and in meadows that are not intensively grazed by livestock. ...
Maximum-likelihood estimates of environmental and broad sense genetic (co)variance components were obtained for the growth and reproductive output of clones of the grass Anthoxanthum odoratum. The clones were transplanted between a mesic and a xeric field site and across-environment genetic correlations were used to estimate the strength of genotype-environment interaction. Significant across-environment clonal covariance matrices were found for several traits, including lifetime reproductive output in one population. None of the matrices differed significantly between populations. Significant within-site clonal variation was found, but there was no significant across-environment clonal covariation. Most broad sense heritability estimates of character states within sites were small (median = 0.12), suggesting that only a slow response to selection is possible. All significant within-site clonal correlations between growth and reproductive output were positive, although the pattern of negative clonal correlations suggests that there may be a cost to first year reproduction, which might constrain future selection response.
... Twenty plants of A. odoratum were collected at random from each of the unlimed (U) and newly limed (NL) subplots in October 1971. There was no duplication of individual genotypes, since plants were collected at least 1 m apart, and A. odoratum is a tufted, short-lived perennial which does not spread vegetatively (Borrill, 1963;Antonovics, 1972). The plants were grown for eight months in boxes of Levington compost, to vegetatively increase the material and to reduce any phenotypic differences caused by the different origins of the populations. ...
... In allopolyploid scenarios, 2x A. alpinum has usually been suggested as one parent [39][40]45,63]. Once again, if we accept the additive model of genome size values (see [62] for details), the most likely second parent according to our dataset is the "Mediterranean diploid" ( Table 1). The sum of mean 2C-values of A. alpinum (5.52 pg) and the perennial "Mediterranean diploid" (7.42 pg) corresponds well to the average holoploid genome size of 4x A. odoratum (12.87 pg/2C). ...
The genus Anthoxanthum (sweet vernal grass, Poaceae) represents a taxonomically intricate polyploid complex with large phenotypic variation and its evolutionary relationships still poorly resolved. In order to get insight into the geographic distribution of ploidy levels and assess the taxonomic value of genome size data, we determined C- and Cx-values in 628 plants representing all currently recognized European species collected from 197 populations in 29 European countries. The flow cytometric estimates were supplemented by conventional chromosome counts.
In addition to diploids, we found two low (rare 3x and common 4x) and one high (~16x–18x) polyploid levels. Mean holoploid genome sizes ranged from 5.52 pg in diploid A. alpinum to 44.75 pg in highly polyploid A. amarum, while the size of monoploid genomes ranged from 2.75 pg in tetraploid A. alpinum to 9.19 pg in diploid A. gracile. In contrast to Central and Northern Europe, which harboured only limited cytological variation, a much more complex pattern of genome sizes was revealed in the Mediterranean, particularly in Corsica. Eight taxonomic groups that partly corresponded to traditionally recognized species were delimited based on genome size values and phenotypic variation. Whereas our data supported the merger of A. aristatum and A. ovatum, eastern Mediterranean populations traditionally referred to as diploid A. odoratum were shown to be cytologically distinct, and may represent a new taxon. Autopolyploid origin was suggested for 4x A. alpinum. In contrast, 4x A. odoratum seems to be an allopolyploid, based on the amounts of nuclear DNA. Intraspecific variation in genome size was observed in all recognized species, the most striking example being the A. aristatum/ovatum complex.
Altogether, our study showed that genome size can be a useful taxonomic marker in Anthoxathum to not only guide taxonomic decisions but also help resolve evolutionary relationships in this challenging grass genus.
... Studies conducted by Borrill (1963) and Jones (1964) showed that triploid hybrids between these species in the wild are probable but unlikely. In the French and Swiss Alps, some tetraploid cytotypes were found in populations of A. alpinum and triploid ones in populations of A. odoratum (Hedberg 1986;Felber et al. 1996). ...
Three Anthoxanthum species are found in Poland: the native A. odoratum L. s. str. and A. alpinum Á. Löve & D. Löve, and the alien A. aristatum Boiss. Major problems within this genus concern: (1) population variation of the native A. odoratum, representing various phases of ecological expansion to anthropogenic habitats; (2) population variation of A. odoratum and A. alpinum along the altitudinal transect; and (3) variation between populations of A. aristatum colonizing new areas and habitats outside its natural range of distribution (chorological expansion). In this study, morphological and anatomical variation of the three Polish Anthoxanthum species was analysed in detail. The variation of A. odoratum and A. aristatum was analysed in respect of environmental differences: habitat types and soil parameters. In the Babia Góra massif, variability distribution along the altitudinal transect was analysed for two vicariants: A. odoratum and A. alpinum. A odoratum in this massif does not cross the upper forest limit (i.e. forest line), and lower montane populations are morphologically very similar to lowland populations. Morphological and anatomical differences were detected between populations of A. alpinum along the altitudinal transect in the Babia Góra massif, with distinct upper montane populations. Moreover, clear morphological differences were found between the two altitudinal vicariants. Lowland populations of A. odoratum are characterized by great morphological variation, only weakly correlated with the type of occupied habitat and the phase of ecological expansion. The detected morphological variation reflects only to a limited extent the environmental variation of occupied habitats, and is not significantly correlated with the phase of chorological expansion. Some soil parameters are significantly correlated with some morphological characters studied in all the Anthoxanthum species. The analysed anatomical features of stems and leaves show continuous variation in the three species.
... De nombreux comptages chromosomiques concernent cette dition. Ainsi, A. alpinum diploïde est connu en Forêt Noire (Bogenrieder et Stietencron, 1985), dans les Vosges (Dersch, 1974), dans le Jura central (Felber, 1986) et dans la majeure partie des Alpes (Bocher, 1961 ;Favarger, 1962 ;Borril, 1963 ;Jones, 1964;Hedberg, 1969Hedberg, et 1970Teppner, 1970 ;Ritter, 1974 ;Scholte, 1977 ;Grossetête, 1982 ;Felber, 1986). En outre, sur la base de leurs résultats non publiés, A. et D. Love (1968) signalent ce cytodème dans les Pyrénées, mais ne donnent pas de stations précises. ...
Cette étude est basée sur les données rapportées dans la littérature ainsi que sur quelque 70 résultats de l'auteur. A. alpinum diploïde occupe les sommets de la Forêt Noire, des Vosges, du Jura central et de la majeure partie des Alpes. A. alpinum tétraploïde, connu avant notre étude dans deux stations seulement, offre une aire relativement étendue puisqu'il remplace le diploïde dans le Jura méridional, sur la frange nord-ouest des Alpes et dans le Massif Central. La présence d'A. odoratum diploïde est signalée pour la première fois en France, dans le massif de l'Estérel (Var). A. odoratum tétraploïde est largement distribué à basse et moyenne altitude. Dans les Pyrénées, ce cytodème atteint en outre des altitudes élevées.
This datasheet on Anthoxanthum odoratum covers Identity, Overview, Distribution, Dispersal, Hosts/Species Affected, Diagnosis, Biology & Ecology, Environmental Requirements, Natural Enemies, Impacts, Uses, Prevention/Control, Further Information.
Wenn man die Literatur der Berichtsjahre überblickt und dabei Vor allem auch die Ergebnisse des Internationalen Botanischen Kongresses in Edinburgh 1964 [Burtt (2)] und anderer Tagungen (z. B. Meeting Bot. Soc. America 1964, Boulder: Amer. J. Bot. 51, 684–689), das große Lehr- und Handbuch der Angiospermen-Taxonomie von P. H. Davis u. Heywood (S. 351) sowie Sammelwerke [etwa Turrill (2); Maheshwari- Vol., J. Ind. Bot. Soc. 42 A, 1963] und Übersichtsreferate [z.B. von Constance (3); Heywood (3); W. Robyns (2)] berücksichtigt, dann lassen sich recht bemerkenswerte neue Entwicklungen und Schwerpunktverschiebungen in der Systematik der Samenpflanzen erkennen: 1. Über die Grundlagen der Systematik, besonders über das Verhältnis zwischen phylogenetischer und phänetischer Klassifikation, ist eine heftige Diskussion in Gang gekommen (S. 349ff.). 2. Die vergleichende Phytochemie („Chemotaxonomy“) und auch die Palynologie (u. a. mit elektronenmikroskopischen Methoden) gewinnen fortwährend an Bedeutung für die Systematik (S. 357 u. S. 373ff.). 3. Die Anwendung mathematischstatistischer Methoden und elektronischer Rechenmaschinen zur Messung von Affinitätsbeziehungen („Numerical Taxonomy“) und die Möglichkeiten der automatischen Datenverarbeitung rücken immer mehr in Griffweite des praktischen Systematikers (S. 376 u. S. 352).
Attempts to infect the four cytodemes of Anthoxanthum odoratum L. s. lat. (Poaceae) with Puccinia sardonensis Gäumann (Uredinales) were successful with half the individuals of A. alpinum A. & D. Löve (diploid and tetraploid) but not with those of A. odoratum s. str. (diploid and tetraploid). For each cytodeme, the sensitivity to the parasite was not dependent on the origin of the material and no correlation was established between the distribution of the rust and that of susceptible individuals. Susceptibility and resistance to P. sardonensis would therefore probably be long‐established characteristics which originated at the time of differentiation of the two diploid taxa of A. odoratum s. str. and of A. alpinum but which preceded their respective polyploidization phases. Resistance to infection would have no adaptive value since resistant A. odoratum is not exposed to infection in nature and probably never has been. These results support the division of A. odoratum s. lat. into A. alpinum and A. odoratum.
Résumé
Des essais d'infection des quatre cytodèmes d' Anthoxanthum odoratum L. s. lat. (Poaceae) par Puccinia sardonensis Gäumann (Urédinée) réussissent sur la moitié des individus d' A. alpinum A. & D. Löve (diploïde et tétraploïde) mais jamais sur ceux d' A. odoratum s. str. (diploïde et tétraploïde). Pour chaque cytodème, la sensibilité au parasite est indépendante de l'origine du matériel et aucune corrélation n'a été établie entre la distribution de la rouille et celle des individus sensibles. La susceptibilité et la résistance à P. sardonensis représenteraient done des caractères anciens dont l'apparition serait contemporaine de la différentiation des deux taxons diploïdes d' A odoratum s. str. et d' A alpinum mais antérieure à leurs phases respectives de polyploïdisation. La résistance à l'infection n'aurait pas de valeur adaptative puisque A. odoratum résistant n'est pas exposé à l'infection dans la nature et ne l'a vraisemblablement jamais été. Ces résultats témoignent de l'indépendance taxonomique d' A alpinum et d' A. odoratum.
Maximum-likelihood estimates of environmental and broad sense genetic (co)variance components were obtained for the growth and reproductive output of clones of the grass Anthoxanthum odoratum. The clones were transplanted between a mesic and a xeric field site and across-environment genetic correlations were used to estimate the strength of genotype-environment interaction. Significant across-environment clonal covariance matrices were found for several traits, including lifetime reproductive output in one population. None of the matrices differed significantly between populations. Significant within-site clonal variation was found, but there was no significant across-environment clonal covariation. Most broad sense heritability estimates of character states within sites were small (median = 0.12), suggesting that only a slow response to selection is possible. All significant within-site clonal correlations between growth and reproductive output were positive, although the pattern of negative clonal correlations suggests that there may be a cost to first year reproduction, which might constrain future selection response.
Trifloreted spikelets in species of Anthoxanthum and of Hierochloe are united by the syndrome of two lower male or neuter florets and a differentiated third floret, perfect, bistaminate, and protogynous. Differences in presentation of the floral organs from the third anthoecium separate the genera. Anthers in Anthoxanthum, longer than the f3 anthoecium, keep it open until they migrate on elongating filaments, following behind the protogynous stigma-styles. Both emerge near the apex of the upper glume which tightly encloses all three florets. In Hierochloe the uppermost anthoecium is closed over the androecium and gynoecium until lodicule-controlled anthesis when stigma-styles are exserted unhindered by glumes, and the anthers are exserted later on long filaments from the chasmogamous lower florets. In Hierochloe triandrous lower florets are constant. In Anthoxanthum the two lower florets are neuter in Eurasian species, but in species in Africa, Asia, and Malesia, sometimes f1 florets are also staminate, and very exceptionally both florets present stamens. These reflect a sexual variability in Anthoxanthum unknown in Hierochloe. Data from flowers of 30 species of Hierochloe and 17 species of Anthoxanthum are tabulated; included are ratios of f3 anthers:anthoecium and stigma-styles:the upper glume, G2, two ratios which most reliably reflect the intergeneric floral patterns. Pathways to those varied floral systems are outlined. A sectional taxonomy is proposed for Hierochloe: Sect. Hierochloe autonymum; Sect. nova Monoecia for species in South America where monoecism occurs in all taxa. Andromonoecism is the predominant sexual system in boreal and austral species of Hierochloe, but is interrupted by apomixis in northern Europe.
Summary An autotetraploidA. alpinum was found in France. In theA. odoratum group only tetraploids were known up to now, but widespreaded diploids have been discovered in Southern Europe. Investigations of karyotypes led to the recognition of six diploid genomes in perennial Anthoxanthums; four were found in diploids, two only in allotetraploids.
An autopolyploid series comprising 2x, 3x and 4x was obtained by colchicining the diploid speciesA. ovatum Lag. The autotriploid, used as seed and pollen parent, was back-crossed to diploid and tetraploid. No significant overall difference was observed in fertility, but there was a tendency for particular pair crosses to the diploid as female parent to show higher levels of seed-setting. This may be associated with the relatively large proportion of haploid pollen that functions when the triploid is used as the male parent.
The effectiveness, in part, of the freely liberated pollen of autotriploidAnthoxanthum in producing progeny, contrasts with the total failure of manually liberated allotriploidDactylis pollen. Triploid sterility may well relate to degree of hybridity.
Genetic unbalance induced by aneuploidy was considered to be more relevant than the “genetic ratio” in seeds, as an explanation of the type of interploid progeny obtained inAnthoxanthum.
Anthoxanthum alpinum Löve & Löve has been described as a diploid perennial distributed in northern Eurasia and the high mountains of central and eastern Europe. Difficulties in finding reliable morphological differences between this taxon and the widespread tetraploid Anthoxanthum odoratum L. have resulted in taxonomists treating them as conspecific, despite the cytological differentiation. The purpose of this study was to use different approaches to assess the relationships between close congeners, such as the pair A. odoratum/A. alpinum. Macromorphological, micromorphological, and molecular data were gathered and analysed for 14 populations representing both taxa from Scandinavia and the Iberian Peninsula. Different cluster analyses were performed to study the relatedness between individuals and populations. Subsequently, a principal components analysis was computed on the basis of macromorphological quantitative traits, and principal coordinates analysis was used to analyse qualitative, micromorphological, and random amplification of polymorphic DNA (RAPD) data. An analysis of molecular variance was applied to the molecular data, and the genetic differentiation between samples was measured using the FST estimator. The results showed that the geographical origin was more important than the ploidy level in explaining the relatedness between specimens and populations. Moreover, a strong correlation was found between the micromorphological traits and environmental parameters. The results of the analyses do not support the assignment of a specific taxonomic rank to A. alpinum. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 156, 237–252.
The author has investigated the karyotypes occurring within Anthoxanthum odoratum L. s. lat. from various parts of its distribution area. Whereas the diploid (2n = 10) seems to be very uniform there exist within the tetraploid (2n = 20) two apparently rather distinct karyotypes. One (karyotype I) is found in the majority of the specimens studied whereas the other (karyotype II) seems to be very rare. This karyotype replicates that of the diploid. Deviations from the strict autotetraploid complement were found to a various extent in all specimens with karyotype II although those specimens must be descendants from recent autotetraploids. It is suggested that further structural changes could have transformed the autotetraploid karyotype into the more or less allopolyploid condition of karyotype I. The present study of meiosis shows that most diploids had regular bivalent formation but some showed univalents and also inversion bridges. In the tetraploids frequent quadrivalents were found as well as multivalents of higher order. In some specimens no irregularities were found in the subsequent stages whereas others showed inversion bridges, laggards, etc. It was as a rule very difficult to obtain hybrids between diploids and tetraploids. A considerable number of hybrids were, however, obtained from a cross tetraploid with karyotype II (♀) × diploids. It is concluded that evidence from several sources indicates that autopolyploidy has played an important rôle in the origin of A. odoratum (4x) and furthermore that it is not possible to maintain the diploid as a separate species.
An intensive study of the cytology and sexual behaviour of the classical Spartina x townsendii agg. and their putative parents in southern England reveals a more complex chromosomal situation than had previously been reported, including aneusomaty in Southampton S. alterniflora populations and in S. x townsendii agg. Chromosome numbers are 2n= 60 and 2n= 62 for S. maritima and S. alterniflora respectively and 2n= 62 and 2n= 120, 122 and 124 (chromosome races) for S. x townsendii F1 and Amphidiploid derivatives respectively. These numbers, though their summation is less precise than hitherto reported, still support the hybridity and amphidiploid origin of S. x townsendii agg. and the process is further confirmed by meiotic pairing data and the discovery of wild backcross hybrids (2n= c.90and 2n=76) near the site of origin at Southampton. The 2n= 62 chromosome number of S. alterniflora, out of line with the x= 10 base number of the genus, is explained as a polysomic condition (2n= 60+ 2) and needs further investigation with a study of North American populations.
It is suggested that chromosome races found in S. x townsendii Amphidiploid will provide adaptive variation in this highly significant and successful amphidiploid.
1.
The analysis of the karyotype morphology of Anthoxanthum odoratum L. (2n=20) and the diploid A. alpinum A. et D. Lve has shown that: a) There is an extra-ordinary degree of inter-plant variation in the tetraploid. b) There are marked differences in the karyotypes of the two species.
2.
It is concluded that odoratum is not autotetraploid but a species of hybrid origin. This denies the diploid-autotetraploid relationship of alpinum and odoratum suggested by earlier workers and substantiates their separate classification.
3.
The karyotypes of the diploids A. aristatum, A. ovatum and an un-named species from Crete, suggest, that odoratum could have evolved from such crosses as alpinum ovatum, alpinum Cretean 2x or ovatum Cretean 2x.
4.
Meiotic analysis of odoratum shows that quadrivalent pairing is prevelant with some associations of six, eight or ten also present in each of the 20 plants studied. Ninety per cent of the multivalents are alternately orientated.
5.
Pairing in the F1 alpinum aristatum is very poor. In the F1 alpinum ovatum pairing is appreciable though erratic and gives evidence of inter-change heterozygosity.
6.
The colchicine amphidiploid of the latter hybrid has complete pairing with some quadrivalents and higher multiples.
7.
It is concluded that odoratum could have evolved from such a plant with selection for increased quadrivalent pairing.
8.
In odoratum and other segmental allotetraploids quadrivalent formation is considered to have a positive role in controlling the qualitative segregation of the ancestral sets.
In mehreren Arbeiten wurde darauf hingewiesen, dab die Art der Entstehung yon polyploiden Populationen fiir deren zgchterischen Wert Pine groBe Bedeutung hat (BEcKER 1960, 1962; SKIEBE 1956, 1958; JAHR 1962 ). Danach ist eine Polyploidisierung tiber unreduzierte Galneten, also auf meiotischem Wege, besser als eine solche auf mitotischem Wege. Es kommt darauf an, polyploide Pflanzen tiber befruchtungsbiologische Vorgfinge zu gewinnen. Wir benStigen daher Methoden, mit welchen meiotische polyptoide Formen in einem zfichterisch notwendigen Umfang bei einem vertretbaren Aufwand hergestellt werden k6nnen. Ffir die Entwieklung eines polyploiden Materials innerhalb einer Art haben wir (JAHR, Si~IEBE U. STEIN 1963) nachgewiesen, dab besonders nach Valenzkreuzungen zwischen 2x- und 4x-Formen h~iufig neue polyploide PIlanzen entstehen. Im folgenden soll als Erweiterung dazu erSrtert werden, wie mall methodisch vorgehen muB, um nach Artkreuzungen ein allopolyploides Ausgangsmaterial auf meiotischem Wege zu gewinnen.
1. Sixteen colchicine treatments, involving five main methods of application and six concentrations, have been used on Triticum interspecific crosses, Triticum—Aegilops intergeneric crosses and Agropyron—Triticum intergeneric crosses.
2. The efficacy of the major treatments in terms of plant survival, plant fertility and ear fertility has been compared, and the most successful method of application has been found to be absorption through the cut leaves—i.e. capping cut-back tillers with a small glass phial containing colchicine.
3. Fertility induced by colchicine is not complete. In plants producing grain, every ear is not necessarily fertile, nor are all spikelets in fertile ears usually fertile.
4. Evidence has been obtained of differential cross response to colchicine action, and also of cross-group response to particular treatments.
SUMMARY1The main taxa of the genus Dactylia are surveyed, illustrating the range of species and subspecies occurring in the group.2The phenotypic characters in nineteen populations, including diploids and tetra-ploids, were analysed in detail; there were large genetic differences between the populations.3The within-population correlation of characters was studied and found to vary independently.4The heritability of some taxonomically-important morphological characters was measured, e.g. panicle length, flag-leaf length, and lemma apex. Each was highly heritable, and capable of independent response to selection.5The between-population correlation of morphological characters was studied. The components of panicle size, flag-leaf length, and lemma apex were related, showing a similar trend in diploids and tetraploids.6The significance of the trend of variation is discussed in relation to taxonomy and evolution.
The average cross fertility is low and influenced by genotype, rather than by the taxonomic position of the parents. A few genotype combinations were reasonably fertile. On the average, crosses were more successful with the tetraploid as the female parent.
The average cross fertility is low and influenced by genotype, rather than by the taxonomic position of the parents. A few genotype combinations were reasonably fertile. On the average, crosses were more successful with the tetraploid as the female parent.
When the triploids, which are functionally male-sterile, were allowed to outcross to diploids and tetraploids some seed setting occurred comparable in extent to the initial crosses. Meiosis is irregular with trivalents, bivalents and univalents; the mean multivalent frequency shows a positive correlation with mean chiasma frequency. Pairing seems to be affected mainly by the genetic constitution of the parents and not by interspecific affinities. The low fertility of the triploids is not surprising in view of the apparently random assortment of the chromosomes to the gametes.
Chromosome numbers of Northern plant species
- A L6ve
- D L6ve
L6vE, A. & D. L6VE (1948). Chromosome numbers of Northern plant species. Univ. Inst. appl. Sci., Dept. Agric. Reports ser. B, No. 3, p. 105, (Reykja-vik).
The artificial hybridisation of grasses The method and technique of selection, breeding and strainbuilding in grasses
- T J Jenkin
- T J Jenkin
JENKIN, T. J. (1924). The artificial hybridisation of grasses. Bull. Welsh Plant Breed. Sta. Series H. No. 2, pp. 18. JENKIN, T. J. (1931). The method and technique of selection, breeding and strainbuilding in grasses. Bull. Bur. Pl. Genet. Aberystwyth 3: 5-34.
BORRILL (I962) Chromosomal status, gene exchange and evolution in Daclylis. 3. The role of the inter-ploid hybrids
- K Jones
JONES, K. & M. BORRILL (I962). Chromosomal status, gene exchange and evolution in Daclylis. 3. The role of the inter-ploid hybrids. Genetica 32: 296-322.
Afro-alpine vascular plants.Symbolae Botanicae Upsalienses XV
- O Hedberg
- O. Hedberg
Cytotaxonomic studies inAnthoxanthum odoratum L.s. lat. 1. Morphologic analysis of herbarium specimens
- I Hedberg
- I. Hedberg
Observations caryologiques et caryosystematiques sur diverses graminées, principalement de la Flore méditerranéenne
- R Litardière
- De
Chromosome numbers of Hungarian plants 2
- L Polya
Cytological investigations onAnthoxanthum alpinum L. et L.Acta
- M Rozmus
- M. Rozmus
Karyotaxonomy inPoaceae. II. Somatic chromosomes of some species
- T Tateoka
Experimental and cytological studies on plant species. VI.Dactylis glomerata andAnthoxanthum odoratum
- T W Böcher
- T. W. Böcher
Synopsis der Deutschen und Schweizer Flora
- W D J Koch
The artificial hybridisation of grasses
- T J Jenkin
- T. J. Jenkin
Chromosome numbers inAnthoxanthum
- G Östergren
- G. Östergren
A note on species pairs in theGramineae
- T G Tutin
- T. G. Tutin
Chromosome numbers of Scandinavian arctic-alpine species
- G Knaben
- G. Knaben
The method and technique of selection, breeding and strainbuilding in grasses
- T J Jenkin
- T. J. Jenkin