Tropical Trees and Forests
Chapters (4)
Successful establishment of the seedling is obviously essential to the development of the tree and remains the most critical phase in the life cycle of a plant (Harper and White, 1975). Mortality amongst seeds and seedlings is much higher than in any other ontogenetic phase. Seed predation is of acute interest to the population biologist since population structure of plants and animals is here closely interrelated (e.g., Janzen, 1970b, 1971). When one considers that the single seedling meristem of a Corypha palm eventually produces about a quarter of a million fruits or seed meristems (Tomlinson and Soderholm, 1975), of which only one is needed to replace the parent tree, the predator pressure and extreme seedling mortality is convincingly demonstrated.
In the previous section features of morphology and growth of trees have been discussed, with a major concern for tropical species; parts and processes have been emphasized, but there has been little discussion of the overall organization of the tree. This aspect becomes the subject of the middle section of the book, in which, tree “architecture” is described in terms of “models” within an “architectural continuum”. These terms have a special application in our usage and need an exact definition.
Trees in the forest rarely exist in the ideal state we have provided for them in our preceding description of architecture. A reader therefore may have had difficulty in recognizing the architectural features we have outlined even with access to tropical species in which there is greatest architectural variety. This is simply because trees rarely conform completely to their model. In the undergrowth of the tropical rain-forests, where microclimatic conditions appear to be optimal for the functioning of trees (Cachan and Duval, 1963), numerous environmental factors still modify their development. Branches are broken mainly by the fall of limbs from trees higher in the canopy, as was shown by Hartshorn (1972) in his study of the population dynamics of Pentaclethra macroloba and Stryphnodendron excelsum in Costa Rica.
Architecture is a concept that can be applied not only to individual plants or their parts, but to all living systems. For example, it has been used by Rollet (1974) to indicate the population characteristics of forests, whereby mathematical relationships are expressed graphically.
... Usually, we define morphological stages based on the number of axes. The later morphological stage usually increases by one axial order compared to the previous morphological stage (Hallé, Oldeman, & Tomlinson, 1978;Mathieu, Cournède, Barthélémy, & Reffye, 2008;Sabatier & Barthélémy, 1999). The results of the morphological analysis of each stage are recorded with a morphological analysis table and outlined by drawings. ...
... Such repetition can be at several levels: the entire tree's axes (total reiteration) or a part of the initial crown (partial reiteration) (Edelin, 1981). The phenomenon of architectural reiteration is often observed in the adult stages, many authors suppose that it is significant to increase the size of the canopy, helping the tree to optimize the surface to absorb light (Edelin, 1984;Hallé et al., 1978). Finally, we reviewed all the different developmental stages and produced a morphological ontogenesis diagram of P. krempfii. ...
... The architecture of the species P. krempfii has features of the Rauh's model (Hallé et al., 1978): rhythmic growth pattern, rhythmic branching, synchronous shoots, lateral reproductive shoots, and radially symmetrical pattern. The bilateral symmetric growth of the axis is often commensurate with the horizontal growth pattern, suitable for low light conditions because these branches are often concentrated in the lower part of the forest canopy (Ninemets & Kull, 1995). ...
The endemic species Pinus krempfii Lecomte. in Bidoup National Park – Lam Dong Province, Vietnam is monopodial woody within morphogenesis and architecture according Rauh’s model typically. Associated with monopodial structure, the branching is rhythmic, lateral flowering, radial symmetry , and the architectural unit within 5 axes. On morphological development, the P. krempfii consists of 3 main stages: seedling, sapling with 5 phases getting along with the arising of first axis to 5 th and the adult carrying reproductive organs and a complete architectural unit. Respectively, the transition of needle morphology and size is observed: wide, slender falcate, bundle with 2 leaves from a short shoot only on seedling and sapling trees; the adults, in addition, bundles with smaller, lanceolate leaves from a short shoot spirally. Essentially, the modification of leaves corresponds to the stages of morphogenesis: the size of leaves decreases with stages on average.
... The architecture of treetops, branches and leaves, the presence of climbing plants and epiphytes, and other abiotic factors determine the creation and control of microclimates in forest ecosystems (Hallé et al., 1978). A vertical gradient with marked microlimatic variation is especially typical of tropical forests (Richards, 1996). ...
... A vertical gradient with marked microlimatic variation is especially typical of tropical forests (Richards, 1996). It is known that towards the highest parts of the canopy moisture decreases while luminosity and temperature increase (Anhuf and Rollenbeck, 2001;Fauset et al., 2017;Hallé et al., 1978;Murakami et al., 2022;Stark et al., 2012). In addition to microclimatic variation, there is vertical stratification of other environmental conditions and resources, including humus and nutrient availability (Catling and Lefkovitch, 1989;Sillett and Van Pelt, 2007;Woods et al., 2015) and, consequently, the plant and animal communities that inhabit parts of trees (Smith, 1973;Stan et al., 2020). ...
... According to Hallé et al. (1978), tree transpiration creates a microclimate at the highest parts of the trunk and in the inner crown, and some groups of epiphytes are adapted to these regions. Cactaceae, for example despite having many xeromorphic characteristics (such as succulence and CAM photosynthesis), occurred predominantly in the inner and middle canopy. ...
Epiphytes are strongly affected by the microclimate of the forest canopy. Therefore, understanding how microclimatic changes are related to the functional characteristics of taxa and the patterns of communities is essential. Our objective was to examine the stratification of the epiphyte community along the vertical gradient of the forests and to investigate whether the pattern of species distribution in the canopy height zones is similar among forests with different characteristics and between the families of epiphytic plants. The study was carried out in the Atlantic Forest of Ilha Grande, in southeastern Brazil, where we recorded 76 species. The highest richness and abundance were found on tree trunks. The high crown had less diversity and a characteristic set of species. The vertical stratification pattern was similar across forests with different phytophysiognomies. The main epiphytic families exhibited different patterns of diversity along the canopy. The highest richness of Araceae occurred in the trunk zones, while Polypodiaceae, Bromeliaceae, and Orchidaceae were more diverse in the trunk and inner crown, and Cactaceae were more diverse in the inner crown. Tree height zones select epiphytic taxa with distinct characteristics according to the fundamental conditions for their survival and, therefore, we suggest that the ecological niche theory is adequate to explain the assembly of epiphytic communities at a local scale.
... To shed light on the post-seminal shoot development of a Detarieae member, we describe the seedling morphology of Copaifera pubiflora Benth. based on plant architectural concepts, which provide means to analyze the nature of growth and branching processes (Barthélémy & Caraglio, 2007;Hallé et al., 1978). As such, plant architecture characterizes the origin of structures and their changes during ontogeny, and each stage of development can be analyzed since germination (Barthélémy & Caraglio, 2007;Puntieri et al., 1999). ...
... Due to its determinate growth, from the unbranched epicotyledonary axis onwards, C. pubiflora has a monochasial, sympodial branching, in which one lateral branch developed after the apex abortion (Barthélémy & Caraglio, 2007). Besides, since the lateral meristem remains inactive during a rest phase protected in an axillary bud, C. pubiflora has a delayed branching pattern (Barthélémy & Caraglio, 2007) often referred to as prolepsis branching (Bell, 2008;Hallé et al., 1978). Delayed branches are usually morphologically recognized by their short proximal internodes and the presence of one or more cataphylls (Barthélémy & Caraglio, 2007), both observed in C. pubiflora. ...
... C. pubiflora and other analyzed species of Copaifera do not possess cataphylls on the epicotyl. This condition is expected since cataphylls or transitional leaves on the epicotyledonary axis very rarely occur in epigeal seedlings (Garwood, 2009;Hallé et al., 1978). In fact, data from Léonard (1957Léonard ( , 1994aLéonard ( , 1994b and Léonard and Doucet (1997) indicate that, apart from some species of Baikiaea, cataphylls on the epicotyl are absent in all other genera within the Detarium clade. ...
Copaifera L. is a woody legume genus with 42 species that produce valuable terpenoid oleoresins used in medicine and industrial activities. Copaifera belongs
to the Detarieae (Detarioideae) and is part of a clade together with five other genera. We describe the seedling morphology of Copaifera pubiflora Benth. based
on plant architectural analysis to shed light on its post-seminal shoot development. Seeds of this species were collected from a wild population in Roraima
State, Brazil. Seedlings of C. pubiflora have preformed shoots with determinate
and rhythmic growth. Each growth unit has two reduced leaf scales that correspond to a pair of prophylls followed by two or three scale-like stipules and one
distal eophyll. Besides, C. pubiflora has a monochasial sympodial branching
with delayed branches. Current evidence indicates that most Copaifera species,
including C. pubiflora, have phanerocotylar, epigeal, reserve seedlings with a
cataphyll-free epicotyl and scale-like structures on the first internode after the
epicotyledonary axis. Based on the available data, a comprehensive view of
Copaifera seedlings from both the Old and New Worlds is also presented.
... Tree architecture is not unplanned (Valladares and Niinemets, 2007) but is controlled by various biotic and abiotic drivers of tree architecture (Lang et al., 2010), their genetical growth plans (Hallé et al., 1978;Tomlinson, 1983;Wu and Hinckley, 2001) and seed dispersal strategy (Malhi et al., 2018). The Biotic and abiotic components that control tree architecture are soil (Zeide and Gresham, 1991;Zeide and Pfeifer, 1991), latitude and solar angle (Oker-Blom and Kellomäki, 1982;Kuuluvainen and Pukkala, 1987;Kuuluvainen, 1992), wind (Cremer et al., 1982;Brüchert and Gardiner, 2006;Nishimura and Setoguchi, 2011;Malhi et al., 2018), temperature (Went, 1953;Moles et al., 2014), available water resources and precipitation (Archibald and Bond, 2003;Scharnweber et al., 2011), competitions (Harper, 1977;Rouvinen and Kuuluvainen, 1997;Muth and Bazzaz, 2003;Juchheim et al., 2017;Seidel et al., 2019a), slope exposition (Umeki, 1995;Harker, 1996;Lang et al., 2010;Johnson et al., 2019), pest and diseases (Holdenrieder et al., 2004;Setiawan et al., 2014), anthropogenic activities (Ramıŕez-Marcial et al., 2001;Schaberg et al., 2008) and altitude (Soethe et al., 2006;Nishimura and Setoguchi, 2011) among others. ...
... There are 23 "architectural models" that are most widely of trees from Tropics and few from the temperate under undisturbed conditions (Hallé and Oldeman, 1970;Hallé et al., 1978). Nomenclature of models is based on the researchers who have studied plant species that represented each model and the models are not species-specific or genus-specific but a representative of all plants on earth (Hollender and Dardick, 2015). ...
... Genetic patterns of syllepsis and prolepsis branching in trees were first noticed in tropical plants (Hallé et al., 1978). The continuous growth of sylleptic bud forms sylleptic branches and proleptic buds after a dormant phase forms proleptic branches (Wu and Hinckley, 2001). ...
Forest stand structure is built by the architecture of individual trees. Individual Tree architecture is affected by genetic and external environmental drivers. This study used high resolution three-dimensional (3D) information on the tree architecture to investigate the relationship between (i) tree’s seed dispersal strategy and (ii) the latitude of the species’ home range (genetical legacy) and the box-dimension of a tree. The latter is a measure of the structural complexity of tree architecture. The aim was to improve our understanding of the development of tree architecture based on fractal analysis. Using a ZEB HORIZON mobile laser scanner, the required 3D data to retrieve the box-dimension was captured. The results indicate that the mean latitude of a tree species’ home range had a significant effect (p<0.001) on the box-dimension of the tested 473 tree species in the Stutel-Arboretum.This indicates that, despite adaptation to the growing conditions in Stutel, the trees exhibited a genetical legacy of the evolutionary adaptation to the latitude of their origin. The coefficient of determination of the relationship was however rather low with R2=0.016. Furthermore, we found a significantly different box-dimension for tree species that rely on wind as a means of seed dispersal as opposed to those relying on animals.
From these results, we conclude that genetic factors contribute notably to the architecture of trees growing in the Arboretum. This architecture can be efficiently studied using the ZEB HORIZON mobile laser scanner.
KEYWORDS
Tree architecture, LiDAR, box-dimension, latitude, seed dispersal strategy, fractal analysis.
... The architecture of treetops, branches and leaves, the presence of climbing plants and epiphytes, and other abiotic factors determine the creation and control of microclimates in forest ecosystems (Hallé et al., 1978). A vertical gradient with marked microlimatic variation is especially typical of tropical forests (Richards, 1996). ...
... A vertical gradient with marked microlimatic variation is especially typical of tropical forests (Richards, 1996). It is known that towards the highest parts of the canopy moisture decreases while luminosity and temperature increase (Anhuf and Rollenbeck, 2001;Fauset et al., 2017;Hallé et al., 1978;Murakami et al., 2022;Stark et al., 2012). In addition to microclimatic variation, there is vertical stratification of other environmental conditions and resources, including humus and nutrient availability (Catling and Lefkovitch, 1989;Sillett and Van Pelt, 2007;Woods et al., 2015) and, consequently, the plant and animal communities that inhabit parts of trees (Smith, 1973;Stan et al., 2020). ...
... According to Hallé et al. (1978), tree transpiration creates a microclimate at the highest parts of the trunk and in the inner crown, and some groups of epiphytes are adapted to these regions. Cactaceae, for example despite having many xeromorphic characteristics (such as succulence and CAM photosynthesis), occurred predominantly in the inner and middle canopy. ...
Epiphytes are strongly affected by the microclimate of the forest canopy. Therefore, understanding how microclimatic changes are related to the functional characteristics of taxa and the patterns of communities is essential. Our objective was to examine the stratification of the epiphyte community along the vertical gradient of the forests and to investigate whether the pattern of species distribution in the canopy height zones is similar among forests with different characteristics and between the families of epiphytic plants. The study was carried out in the Atlantic Forest of Ilha Grande, in southeastern Brazil, where we recorded 76 species. The highest richness and abundance were found on tree trunks. The high crown had less diversity and a characteristic set of species. The vertical stratification pattern was similar across forests with different phytophysiognomies. The main epiphytic families exhibited different patterns of diversity along the canopy. The highest richness of Araceae occurred in the trunk zones, while Polypodiaceae, Bromeliaceae, and Orchidaceae were more diverse in the trunk and inner crown, and Cactaceae were more diverse in the inner crown. Tree height zones select epiphytic taxa with distinct characteristics according to the fundamental conditions for their survival and, therefore, we suggest that the ecological niche theory is adequate to explain the assembly of epiphytic communities at a local scale.
... The tropical rain forests are very rich in species with large interspecific differences in chemical composition (Grubb and Edwards 1982;Hobie 1992), and they differ in species competition and structure over sometimes short distances (Trichon 1996). Moreover, the tropical forests are very dynamic systems, mosaic of regenerating and mature "phases" (Halle et al. 1978;Whitmore 1984). This invariably rises the question of the representativeness of field samples that are always small for obvious logistic reasons, when extrapolating the data to the whole ecosystem. ...
... Following previous research on forest dynamics in that area by Torquebiau (1986) andLaumonier (1991), several criteria were taken into account for the selection of what can be seen as representative of mature and "old" building forest phases. For the particular purpose of the study a former classification of the forest dynamics made by Laumonier (op.cit), was combined with Whitmore (1984) tree diameter classes for mature, building and gap phases, and refined using vertical and horizontal structure criteria e.g : -frequency histogram for diameters and heights, -scatter and profile diagrams, -crown projection, canopy cover, crown overlapping, -treefall gaps and added with a concept by Halle et al. (1978) that classifies trees according to their architecture: 1) Trees of the "Future" which are represented by the first stage of development when either conform to their original model or are regenerated by reiteration, 2) Trees of the "Present" are trees that survive from earlier phase of development, show no regeneration in an architectural sense as a whole and have established a new energetic balance, and 3) Trees of the "Past" are trees that show no particular response to the outside energy, facing an architectural chaos from disturbance and are gradually eliminated. ...
Studies of nutrient cycling of tropical forests should differentiate between dynamic stages of the forest. We studied the nutrient concentration (N, P, K, Ca and Mg) and phytomass of aboveground (living and non living parts) and belowground compartments (soil) in four dynamic stages, namely Building (Bl and B2), and Mature (Ml and M2) stages, for a lowland rain forest. Nutrient concentrations in various compartments differed between the dynamic stages. Bark contains higher nutrient concentration than wood parts, both in stems and branches. Leaves contain higher nutrient concentration than wood parts, both in litterfall and litter. The concentration of K in throughfall is the highest, Ca and Mg perform similar value. Throughfall exhibits lower nutrient concentration than open area rain water. The nutrient concentration of 10-20 cm is higher than in the 0-10 cm soil depth. The phytomass values are highly variable among tree parts, diameter classes and dynamic stages. The phytomass is generally the highest in M2 and significantly different from Bl , Ml and B2. The phytomass of leaves in litterfall and litter is higher than wood parts. More litterfall and litter are accumulated in mature than building phases. Key words : nutrient / phytomass / dynamics / rain / forest
... For example, ivy (Hedera helix) was seen as a model species [6] without recognition that flowering and fruiting only occurs on plagiotropic sylleptic branches with distichous leaf phyllotaxis. In contrast, the mainstem and proleptic branches with characteristic "juvenile" leaf shape and radial phyllotaxis can climb up trees, walls or cliff faces to heights well above the sylleptic branches [7]. Typically, good rooting ability was attributed to mainstemtype 'juvenile' cuttings, while poor rooting ability was attributed to 'mature' cuttings taken from sylleptic branch type cuttings. ...
For centuries, stem cuttings harvested from sexually mature trees have been recognized to be more difficult to root than those from juvenile shoots. This has been poorly understood and attributed to a combination of ontogenetic and physiological ageing. The recent suggestion that micro-RNA may play a key role in phase change has stimulated a re-examination of some old data that identified pre-severance light x nutrient interactions affecting the rooting ability of stem cuttings. This was linked to vigorous growth and active photosynthesis without constraint from accumulated starch. Support for the prime importance of physiological factors was also obtained when seeking to induce physiological youth in the crowns of ontogenetically mature trees by the induction of roots within the tree crown. Meanwhile, at the other end of the phase change spectrum, floral initiation occurred when the opposite set of environmental conditions prevailed so that growth was stunted, and carbohydrates accumulated in leaves and stems. A re-examination of this literature suggests that rooting ability is driven at the level of an individual leaf and internode emerging from the terminal bud affecting both morphological and physiological activity. In contrast, flowering occurs when internode elongation and assimilate mobilization were hindered. It is therefore suggested that the concepts of juvenility and ageing are not relevant to vegetative propagation and should instead be replaced by physiological and morphological 'fitness' to root.
... Individuals were identical within species (same model F I G U R E 2 Morphological diversity of tree species illustrating strong differences between species. (a) Diversity of tree species architecture and height in a tropical forest (Hallé et al., 1978). Coordinates are in m; (b) Diversity of seed size and shape from 17 tree species of the Fabaceae family in the Peruvian Amazon (Muller-Landau, 2003); (c) Diversity of leaf size and shape (herbarium of Cayenne, Gonzalez et al., 2021) and of wood aspect (reflecting wood characteristics) and density (Normand et al., 2017) parameters for all conspecific individuals), but different between species (different model parameters between heterospecific individuals). ...
Intraspecific variability (IV) has been proposed as a new track to explain species coexistence. Previous studies generally assumed that IV results from intrinsic differences between conspecifics that widen species’ fundamental niches and blur differences among species, thus impeding stable coexistence, but also slowing down the rate of competitive exclusion. Based on a body of evidence, we here argue that IV does not necessarily imply differences among conspecifics, nor species niches overlap: conspecifics differ in their measured attributes mainly due to differences in the micro-environment they thrive in. Consequently, they respond more similarly to environmental variation than heterospecifics, thereby concentrating competition within species – a necessary condition for species coexistence. We call for new studies exploring observed IV as an outcome of species-specific responses to high-dimensional environmental variations that can lead to inversions of species hierarchy in space and time promoting stable coexistence.
... Indeed, when a forest tends towards maturity, the canopy is relatively closed, which tends to impede the growth and development of other woody species (light-demanding species). On the other hand, as part of the silvigenetic cycle described by [51], when an environment tends towards maturity, we tend to observe natural mortality of short-lived pioneer species such as Musanga cecropioides, Macaranga spp…, to leave the place to the long-lived pioneer species such as Nauclea diderrichii, Erythrophleum suaveolens [52]. Nonetheless, Musanga cecropioides and Macaranga spp are fast-growing species growing on relatively rich clay soils. ...
... Individuals were identical within species (same model F I G U R E 2 Morphological diversity of tree species illustrating strong differences between species. (a) Diversity of tree species architecture and height in a tropical forest (Hallé et al., 1978). Coordinates are in m; (b) Diversity of seed size and shape from 17 tree species of the Fabaceae family in the Peruvian Amazon (Muller-Landau, 2003); (c) Diversity of leaf size and shape (herbarium of Cayenne, Gonzalez et al., 2021) and of wood aspect (reflecting wood characteristics) and density (Normand et al., 2017) parameters for all conspecific individuals), but different between species (different model parameters between heterospecific individuals). ...
Intraspecific variability (IV) has been proposed to explain species coexistence in diverse communities. Assuming, sometimes implicitly, that conspecific individuals can perform differently in the same environment and that IV increases niche overlap, previous studies have found contrasting results regarding the effect of IV on species coexistence. We aim at showing that the large IV observed in data does not mean that conspecific individuals are necessarily different in their response to the environment
and that the role of high-dimensional environmental variation in determining IV has largely remained unexplored in forest plant communities. We first used a simulation
experiment where an individual attribute is derived from a high-dimensional model, representing “perfect knowledge” of individual response to the environment, to illustrate how large observed IV can result from “imperfect knowledge” of the environment. Second, using growth data from clonal Eucalyptus plantations in Brazil, we estimated a major contribution of the environment in determining individual growth.
Third, using tree growth data from long-term tropical forest inventories in French Guiana, Panama and India, we showed that tree growth in tropical forests is structured spatially and that despite a large observed IV at the population level, conspecific individuals perform more similarly locally than compared with heterospecific individuals. As the number of environmental dimensions that are well quantified at fine scale is generally lower than the actual number of dimensions influencing individual at-
tributes, a great part of observed IV might be represented as random variation across individuals when in fact it is environmentally driven. This mis-representation has important consequences for inference about community dynamics. We emphasize that observed IV does not necessarily impact species coexistence per se but can reveal species response to high-dimensional environment, which is consistent with niche theory and the observation of the many differences between species in nature.
... This made it possible to evaluate eucalypt rust severity, since the leaves are similar from this stage onward and no infection by A. psidii was found after stage 5. The classification into five growth stages based on leaf ontogeny and an image scale for leaf differentiation is widely used for rubber tree leaves [29] to evaluate a Pseudocercospora ulei-rubber tree pathosystem [30,31]. The quantification of rust on eucalypt leaves and their resistance to this disease must be carried out using the first to third leaf pairs, since the disease decreases after the third leaf stage onward [15,22]. ...
The fungus Austropuccinia psidii infects young tissues of Eucalyptus plants until they are two years old in the nursery and field, causing Myrtaceae rust. The characteristics making older eucalypt leaves resistant to A. psidii and the reason for the low levels of this pathogen in older plants need evaluations. The aim of this study was to evaluate the morphological differences between Eucalyptus grandis leaves of different growth stages and two plant ages to propose a visual phenological scale to classify E. grandis leaves according to their maturation stages and to evaluate the time of leaf maturation for young and adult plants. A scale, based on a morphological differentiation for E. grandis leaves, was made. The color, shape and size distinguished the leaves of the first five leaf pairs. Anatomical analysis showed a higher percentage of reinforced tissue, such as sclerenchyma-like tissue and collenchyma, greater leaf blade thickness, absence of lower palisade parenchyma in the mature leaves and a higher number of cavities with essential oils than in younger ones. Changes in anatomical characteristics that could reduce the susceptibility of older E. grandis leaves to A. psidii coincide with the time of developing leaf resistance. Reduced infection of this pathogen in older plants appears to be associated with a more rapid maturation of their leaf tissues.
... The microclimate modifications possible in biodiverse agroforestry systems largely depend on shade tree selection (van Oijen et al., 2010b), due to large differences in shade tree architectural characteristics and leaf functional traits, both interspecifically (Hallé et al., 1978) and ...
Biodiverse agroecosystems, including agroforestry, are characterized by complicated multispecies interactions, and it is this complexity that can be exploited for crop protection against pathogens and disease management practices. However, the effectiveness of biodiverse agroecosystems in minimizing disease depends on a range of biotic and abiotic interactions, thus requiring deep understanding of the multifunctionality within these systems. Using a functional trait-based approach, my PhD thesis aims to establish a link between multispecies functional traits in agroforestry systems and disease dynamics. As a model system, I use an economically significant tree-crop, Coffea arabica var. Caturra (coffee), grown in biodiverse agroforestry systems, and one of its equally significant foliar pathogens Hemileia vastatrix, causal agent of Coffee Leaf Rust. I found that shade tree leaf and canopy traits in these agroforestry systems are significantly related to microclimate modifications that uniquely impact pathogens and disease incidence, highlighting the nuances between agroforestry systems. Similarly, coffee leaf functional trait trade-offs show significant shifts in diseased systems. However, disease incidence does not impact the root functional trait expression of coffee. From a theoretical perspective, this research enhances our understanding of multispecies functional traits and ecosystem processes in diseased systems, opening a new dimension for functional trait research. iii From an applied perspective, this research demonstrates how the multifunctionality of biodiverse agroforestry systems can be optimized for crop protection and integrated into disease management practices. I provide novel information to better inform biodiverse farm design and management, as well further promote the adoption of agrobiodiversity into our agricultural landscapes.
Before developing orchard management strategies, it is crucial to conduct architectural analysis at the shoot level for the specific type of fruit to be grown. The objective of this study was to analyze flowering patterns in 1-year-old long shoots of three apple cultivars ('Amasya,' 'Braeburn,' and 'Granny Smith') with different bearing behaviors. This analysis aimed to gain a better understanding of their growth dynamics and reproductive activities. The shoot was divided into three consecutive zones (proximal, median, and distal) based on node number. When comparing the number of floral and vegetative buds in the three zones along the shoot, less contrast was observed between alternate-bearing ('Amasya') and regular-bearing cultivars ('Braeburn' and 'Granny Smith'). However, a notable difference in floral bud quality variables was evident in shoot zones between biennial-bearing and regular-bearing cultivars. In 'Braeburn' and 'Granny Smith' with a regular bearing habit, floral bud quality variables remained stable along the shoot. In contrast, 'Amasya' shoots exhibited a gradual increase in floral bud quality from the proximal zone towards the distal zone. This study underscores the significance of floral bud quality, especially the properties of spur leaves along the shoot, in ensuring optimal and consistent productivity. Finally, with the exception of internode length, morphometric traits did not significantly differ between cultivars when considering the entire shoot. However, these differences became apparent when examining successive zones along the shoot.
Modeling and simulating the growth of the branching architecture of tree species remains a challenge. With existing approaches, we can reconstruct or rebuild the branching architectures of real tree species, but the simulation of the growth process remains unresolved. First, we present a tree growth model to generate branching architectures that resemble real tree species. Second, we use a quantitative morphometric approach to infer the shape similarity of the generated simulations and real tree species. Within a functional-structural plant model (FSPM), we implement a set of biological parameters that affect the branching architecture of trees. By modifying the parameter values, we aim to generate basic shapes of spruce, pine, oak, and poplar. Tree shapes are compared using geometric morphometrics of landmarks that capture crown and stem outline shapes. Five biological parameters, i.e. xylem flow, shedding rate, proprioception, gravitysense, and lightsense, most influenced tree branching and their adjustments led to the generation of different spruce, pine, oak, and poplar shapes. The largest effect was attributed to gravity, as phenotypic responses to this effect resulted in different growth directions of gymnosperm and angiosperm branching architectures. Since we were able to obtain branching architectures that resemble real tree species by adjusting only a few biological parameters, our model is extendable to other tree species. Furthermore, the model will also allow the simulation of structural tree-environment interactions. Our simplifying approach to shape comparison between tree species, landmark geometric morphometrics, showed that even the crown-trunk outlines capture species differences based on their contrasting branching architectures.
Scaling patterns in plants have long interested biologists, particularly whether different species share similar patterns of growth, and whether differences in growth trajectories depend on plant size. Using 8,794,737 measurements for 285 species from the U.S. Forest Inventory and Analysis database, we test several predictions emerging from a recently published “flow similarity” model for plant growth and allometry. We show that the model's predicted curvature for intraspecific relationships between height, dbh, and biomass is found in 88.1% of examined cases, and empirical slopes fall as predicted between the elastic similarity and flow similarity predictions in 71.1% of cases. We also find a strong size dependence in observed intraspecific allometric exponents, with large species, particularly gymnosperms, converging near the expectation for elastic similarity and the central tendency among small species approaching the expectations for flow similarity in most cases. Our results support the idea that differences in growth patterns across plant species depend on plant size and their attendant hydraulic and/or biomechanical demands and helps to delineate the bounds of the theoretical morphospace in which they occur.
Capurodendron is the second largest endemic genus of vascular plants in Madagascar. It comprises mainly trees that are frequently logged for their valued wood. This, together with deforestation, led to 76% of the known species being Endangered or Critically Endangered. However, a confident species identification is often not possible with the current available literature and many morphotypes do not fit any described taxa, which has impeded the implementation of conservation measures. We performed a phylogenomic revision studying c. 900 collections morphologically, and sequencing 638 nuclear genetic markers of 180 representative specimens up to 90 years old, including all the described species and some undescribed morphotypes. Our results show that Capurodendron may contain up to 21 undescribed species in addition to the 35 already known. Nine of these are confirmed as valid species supported by genetic, morphological, and ecological data, and we describe them here (Capurodendron ainae, C. ambanizanense, C. antilahimenae, C. christeae, C. nataliae, C. ratovosonii, C. razakamalalae, C. sommerae, and C. vulcanicola). For the remaining 12 candidate new species, three are genetically analysed but require more sampling, and nine are only supported by morphological and ecological data so far, and therefore require genetic analyses to confirm their validity. For practical purposes and to assist with conservation assessments we provide an identification key, based mainly on vegetative characters, that also include the undescribed species.
In plant ecology, the terms growth and development are often used interchangeably. Yet these constitute two distinct processes. Plant architectural traits ( e.g. number of successive forks) can estimate development stages. Here, we show the importance of including the effect of development stages to better understand size‐related trait scaling relationships ( i.e. between height and stem diameter).
We focused on one common savanna woody species ( Senegalia nigrescens ) from the Greater Kruger Area, South Africa. We sampled 406 individuals that experience different exposure to herbivory, from which we collected four traits: plant height, basal stem diameter, number of successive forks (proxy for development stage), and resprouting. We analysed trait relationships (using standardized major axis regression) between height and stem diameter, accounting for the effect of ontogeny, exposure to herbivory, and resprouting.
The number of successive forks affects the scaling relationship between height and stem diameter, with the slope and strength of the relationship declining in more developed individuals. Herbivory exposure and resprouting do not affect the overall height–diameter relationship. However, when height and stem diameter were regressed separately against number of successive forks, herbivory exposure and resprouting had an effect. For example, resprouting individuals allocate more biomass to both primary and secondary growth than non‐resprouting plants in more disturbed conditions.
We stress the need to include traits related to ontogeny so as to disentangle the effect of biomass allocation to primary and secondary growth from that of development in plant functional relationships.
Agroforestry systems (AFS) represent combinations of trees, arable crops, and/or pastures. Being assemblages of diverse life-forms, they exhibit complex biophysical interactions. For instance, the multistrata canopies shade the understory crops by intercepting a significant amount of the incoming solar radiation. Optimizing understory productivity, thus, requires understanding the elements that affect the canopy transmittance of photosynthetically active radiation (PAR) and its spatiotemporal dynamics. We systematically reviewed the peer-reviewed literature involving 145 tropical and subtropical tree + crop combinations. The theoretical underpinnings of interspecific interactions in developing agroforestry stands were elucidated using a conceptual model. Additionally, the linkage between subcanopy PAR levels and yield was established for 11 arable crops. PAR reaching the understory and the subcanopy yield levels were tremendously variable across AFS. Relative yields ranged from 6 to 188% of the sole crops. Stage of stand development, canopy architecture, and management factors are cardinal determinants of canopy light extinction, understory PAR availability, and yield. The yield of shade-tolerant crops either increased (“over-yielding”) or remained the same as PAR levels decreased within certain limits, albeit with intraspecific variations. The tree-crop interaction effects on yield were positive, negative, or neutral. In total, 19 cases showed positive responses, 29 were neutral, and 113 were negative, with a few overlapping responses depending on the tree, crop, and management. This implies that the key to ecological intensification is component selection and management. Agroforestry, while containing the loss of, maintaining, or even increasing understory yields, thus maximizes overall (tree + crop) outputs and land equivalent ratio.
The structure of specialized vegetative shoots of conifers performing a trophic function has not been suffi ciently studied. The purpose of the work was to describe and classify phyllomorphic branches, as well as to identify the adaptations of conifers to the formation of such specialized trophic shoots. Phyllomorphic branches are fl attened dorsoventral shoots or systems of shoots with a non–thickened axis and opposite or regular double-row leaves. About 250 species of 42 genera of modern conifers cultivated in botanical gardens of Russia were studied. The main research method was a comparative morphological analysis of shoot systems, individual shoots and leaves. Several structural types of phyllomorphic branches have been identifi ed, each of which has its own variants: 1. Classical double-row fl at needle-shaped leaves with a thin axis (Abies, Amentotaxus, Cephalotaxus, Keteleeria, Picea, Podocarpus, Prumnopitys, Pseudotaxus, Pseudotsuga, Sequoia, Taxus, Torreya, Tsuga); 2. Phyllomorphic branches in the form of dorsiventral, branched in one plane systems of shoots (Chamaecyparis, Thuja, Glyptostrobus, Metasequoia, Taxodium); 3. Phyllomorphic branches that have phyllocladia instead of leaves (species of the genus Phyllocladus).
The article focuses on the growth rates of three extant species belonging to the tribe Sequoiaceae: Metasequoia glyptostroboides , Sequoia sempervirens and Sequoiadendron giganteum . The material was collected from botanical garden collections on the Black Sea coast of the Caucasus and Crimea. During a long growing season, all three species form shoot systems of varying complexity: from unbranched shoots consisting of a single elementary shoot to sylleptically branched multi-axial systems. In S. giganteum , the shoot systems formed during an extra-bud growth period are similar to those of other Cupressaceae species and partly to those of Pinaceae. In Metasequoia glyptostroboides and Sequoia sempervirens , sylleptically branched shoot systems are differentiated into several variants: on orthotropic shoots in the upper part of the growth, plagiotropic branches are sylleptic and continue to grow after the orthotropic part of the shoot system has stopped growing. Plagiotropic sylleptic lateral shoots continue to branch into second-order lateral shoots. Similar structures are found in Araucaria and archaic fossil conifers. M. glyptostroboides and S. sempervirens have phyllomorphic branches of the same appearance as those described for Tsuga canadensis . Plagiotropic lateral sylleptic shoots continue to branch into second-order lateral shoots. Similar structures are known in Araucaria and fossil archaic conifers. M. glyptostroboides and S. sempervirens have phyllomorphic branches of the same appearance as described for Tsuga canadensis . These species are also characterized by buds formed serially below the sylleptically growing shoot. In M. glyptostroboides , the phyllomorphic branches fall off annually, and their perennial bases form a growing, basisympodially shortened shoot. The renewal bud is not located under the bark, as in Taxodium distichum .
Secondary sexual dimorphism (SSD) in flowering plants is expressed by sexual differences of characters that are not directly related to gamete production. The leaf C/N ratio, photosynthetic traits or clonal responses have never been studied in relation to SSD in yerba‐mate. It was hypothesized that leaf and plant photosynthesis are higher in female than in male individuals because females must supply photoassimilates to compensate for the additional reproductive investments of SSD in biomass. Here, we investigated how two contrasting light environments (monoculture—MO and agroforestry—AFS) and plant genders change leaf and plant photosynthesis, plant architecture, leaf and branch biomass production and C and N investments of two male and two female clones. To model the 3D yerba‐mate structure, virtual trees were constructed using measurements of plant morphology using VPlant modelling software. The light‐response curves of leaf CO2 assimilation were used to model instantaneous leaf and daily plant photosynthesis. Photosynthetic traits derived from light‐response curves did not differ between MO and AFS. Some architectural traits were segregated sexually only in MO, while some physiological ones only in AFS. Leaf photosynthesis was higher in females than in males in AFS over a large part of the diurnal cycle, but SSD was not expressed in carbon gains at plant or daily scales. Leaf C/N ratio was higher in MO than in AFS, indicating MO as an ecosystem with higher degree of environmental degradation. Female clones had leaves with lower C/N ratio than males in both systems, relating to higher leaf photosynthesis on an area basis in females. SSD expressed in leaf photosynthesis over a large part of the diurnal cycle in AFS was not observed in carbon gains at plant or daily scales, indicating that the integration of physiology and architecture equalized the gender specificities. The insensitivity of photosynthetic traits derived from light‐response curves indicated acclimation of yerba‐mate leaves to a wide range of incoming light.
Thiswork aims to model the mechanical processes used by tree branches to control their posture despite their increasing weight loading. The two known options for a branch to maintain its orientation are the asymmetry of maturation stress, including reactionwood formation, and eccentric radial growth. Both options can be observed in nature and influence the stress distribution developed in the branch each year. This so-called ”growth
stress” reflects the mechanical state of the branch. In this work, a growth stress model was developed at the cross-section level in order to quantify and study the biomechanical impact of each process. For illustration, this model was applied to branches of two 50-year-old trees, one softwood Pinus pinaster, and one hardwood Prunus avium (wild cherry tree), both simulated with the AmapSim discrete element software. For the wild cherry tree, the computed outputs highlighted that the eccentricity of radial growth seems to be as efficient as the formation of reaction wood to maintain postural control despite the increasing gravity. For the pine tree, eccentric radial growth appears to be less efficient than the formation of reaction wood. But although it does not necessarily act as a relevant lever for postural control, it greatly modifies the profile pattern of mechanical stress and could provide mechanical safety of the branch. This work opens
experimental perspectives to understand the biomechanical processes involved in the formation of branches and their mechanical safety.
The interception of rainfall by plant canopies alters the depth and spatial distribution of water arriving at the soil surface, and thus the location, volume, and depth of infiltration. Mechanisms like stemflow are well known to concentrate rainfall and route it deep into the soil, yet other mechanisms of flow concentration are poorly understood. This study characterises pour points, formed by the detachment of water flowing on the lower surface of a branch, using a combination of field observations in Western Australian banksia woodlands and rainfall simulation experiments on Banksia menziesii branches. We aim to establish the hydrological significance of pour points in a water-limited woodland ecosystem, along with the features of the canopy structure and rainfall that influence pour point formation and fluxes.Pour points were common in the woodland and could be identified by visually inspecting trees. Water fluxes at pour points were upto 15 times rainfall and were usually comparable to or greater than stemflow. Soil water content beneath pour points was greater than in adjacent control profiles, with 20-30% of seasonal rainfall volume infiltrated into the top 1m of soil beneath pour points, compared to 5% in controls. Rainfall simulations showed that pour points amplified the spatial heterogeneity of throughfall, violating water balance closure assumptions. The simulation experiments demonstrated that pour point fluxes depend on the interaction of branch angle and foliation for a given branch architecture. Pour points can play a significant part in the water balance, depending on their density and rainfall concentration ability.
Plant architecture strongly influences plant growth habits, as it determines the arrangement, function and fate of meristems. How architecture could be involved in the monocarpic life history, i.e. dying after flowering, remains poorly investigated. Monocarpy is evident in some species since they are annual or because their single stem flowers apically. However, monocarpy in long-lived branched trees is rare and remains poorly understood. We aim to highlight the architectural features involved in the monocarpic strategy of Cerberiopsis candelabra, a rainforest tree endemic to New Caledonia. We conducted a comparative analysis of the genus, which comprises three species with different growth habits. Twenty plants of each species were studied at different ontogenic stages. We compared their developmental sequence and analysed their processes of growth, branching, flowering and reiteration. We identified a combination of traits that distinguish the species, and we found a syndrome of two architectural features that support the monocarpic strategy in C. candelabra: the synchronous flowering of all terminal meristems and the absence of delayed branching. Flowering in C. candelabra preferentially occurs when the complete architectural sequence is developed, but the plant never shows signs of senescence, suggesting that environmental stresses, such as wind disturbance, could be the main trigger for flowering. The architecture of C. candelabra is suggested to be the most derived in the genus.
Tree training systems for temperate fruit have been developed throughout history by pomologists to improve light interception, fruit yield, and fruit quality. These training systems direct crown and branch growth to specific configurations. Quantifying crown architecture could aid the selection of trees that require less pruning or that naturally excel in specific growing/training system conditions. Regarding peaches [Prunus persica (L.) Batsch], access tools such as branching indices have been developed to characterize tree‐crown architecture. However, the required branching data (BD) to develop these indices are difficult to collect. Traditionally, BD have been collected manually, but this process is tedious, time‐consuming, and prone to human error. These barriers can be circumnavigated by utilizing terrestrial laser scanning (TLS) to obtain a digital twin of the real tree. TLS generates three‐dimensional (3D) point clouds of the tree crown, wherein every point contains 3D coordinates (x, y, z). To facilitate the use of these tools for peach, we selected 16 young peach trees scanned in 2021 and 2022. These 16 trees were then modeled and quantified using the open‐source software TreeQSM. As a result, “in silico” branching and biometric data for the young peach trees were calculated to demonstrate the capabilities of TLS phenotyping of peach tree‐crown architecture. The comparison and analysis of field measurements (in situ) and in silico BD, biometric data, and quantitative structural model branch uncertainty data were utilized to determine the reconstructive model's reliability as a source substitute for field measurements. Mean average deviation when comparing young tree (YT) height was approx. 5.93%, with crown volume was approx. 13.26% across both 2021 and 2022. All point clouds of the YTs in 2022 showed residuals lower than 12 mm to cylinders fitted to all branches, and mean surface coverage greater than 40% for both the trunk and primary branching orders.
Life on Earth depends on the conversion of solar energy to chemical energy by plants through photosynthesis. A fundamental challenge in optimizing photosynthesis is to adjust leaf angles to efficiently use the intercepted sunlight under the constraints of heat stress, water loss and competition. Despite the importance of leaf angle, until recently, we have lacked data and frameworks to describe and predict leaf angle dynamics and their impacts on leaves to the globe. We review the role of leaf angle in studies of ecophysiology, ecosystem ecology and earth system science, and highlight the essential yet understudied role of leaf angle as an ecological strategy to regulate plant carbon–water–energy nexus and to bridge leaf, canopy and earth system processes. Using two models, we show that leaf angle variations have significant impacts on not only canopy‐scale photosynthesis, energy balance and water use efficiency but also light competition within the forest canopy. New techniques to measure leaf angles are emerging, opening opportunities to understand the rarely‐measured intraspecific, interspecific, seasonal and interannual variations of leaf angles and their implications to plant biology and earth system science. We conclude by proposing three directions for future research.
We document the habit and affinity of the most complete Mesozoic Era tree to be excavated in the UK. The fossil was found in situ in a palaeosol of the Upper Jurassic Purbeck Group of southern England (Tithonian: ca. 150–145 million years). It comprises over 100 permineralized (silicified) pieces that represent a rooted stump and fallen trunk, together weighing more than two tonnes. This exceptional specimen was excavated in a manner that retained the original associations among its parts, providing a unique insight into the overall habit and mode of growth. A laser scanning approach was used to facilitate the investigation, producing the largest 3D reconstruction of a plant fossil. Anatomical details reveal that the wood belongs to the fossil-genus Agathoxylon. Despite an estimated growth age of more than 200 years, the tree was of modest size, not greatly exceeding 12 m in height. The main trunk bifurcated, developing into a decurrent, spreading crown. Its habit differed significantly from most modern arborescent conifers, which have pole-like central trunks and narrow, conical crowns, and from known growth forms in the Cheirolepidiaceae, an important extinct group of Mesozoic conifers. These findings extend our knowledge of the growth architecture of Jurassic conifers, which were prominent and diverse elements of seasonally arid, low to mid-latitude coastal communities during the Late Mesozoic.
This introducing chapter explains the importance of forestry as primary wood producer as well as the sources of wood. Starting point is the Sect. 1.1.1, “Global Forest Resources,” which provides basic data and information on global forests and forest area. The main functions of forests and how forests provide various goods and ecosystem services are described.This global perspective is followed by the Sect. 1.2, “European Forestry,” explaining the development of European forests and its forestry as well as the principle of sustainability, which was developed within the European forestry (or silviculture).The Sect. 1.3, “Forestry and Wood Production” introduces forest management types and describes the global wood production. Furthermore, different definitions around trees, wood, and timber are given, and it is briefly explained how tree growth and wood quality can be influenced by forestry measures.The Sect. 1.4, “Forestry and Environment” is dealing with the general effects of forestry on nature, climate, and water balance, considering current challenges like climate change, conservation of nature, and biodiversity.Finally, the Sect. 1.5, “Wood Within the Value Chain” reflects some aspects like the tracking of wood, legality of forestry, and competition of wood with other materials.KeywordsGlobal forest resourcesForestrySustainabilityForest functionsChain of custody
Perennial para- and endo-dormancy are seasonally separate phenomena. Whereas para-dormancy is the suppression of axillary buds (AXBs) by a growing shoot, endo-dormancy is the short-day elicited arrest of terminal and AXBs. In hybrid aspen (Populus tremula x P. tremuloides) compromising the apex releases para-dormancy, whereas endo-dormancy requires chilling. ABA and GA are implicated in both phenomena. To untangle their roles, we blocked ABA biosynthesis with fluridone (FD), which significantly reduced ABA levels, downregulated GA-deactivation genes, upregulated the major GA3ox-biosynthetic genes, and initiated branching. Comprehensive GA-metabolite analyses suggested that FD treatment shifted GA production to the non-13-hydroxylation pathway, enhancing GA4 function. Applied ABA counteracted FD effects on GA metabolism and downregulated several GA3/4 -inducible α- and γ-clade 1,3-β-glucanases that hydrolyse callose at plasmodesmata (PD), thereby enhancing PD-callose accumulation. Remarkably, ABA-deficient plants repressed GA4 biosynthesis and established endo-dormancy like controls but showed increased stress sensitivity. Repression of GA4 biosynthesis involved short-day induced DNA methylation events within the GA3ox2 promoter. In conclusion, the results cast new light on the roles of ABA and GA in dormancy cycling. In para-dormancy, PD-callose turnover is antagonized by ABA, whereas in short-day conditions, lack of GA4 biosynthesis promotes callose deposition that is structurally persistent throughout endo-dormancy. This article is protected by copyright. All rights reserved.
Plant architecture is the science of stem arrangements in plants. A stem (or axis) consists of at least one internode bearing a lateral leaf and an apical meristem. Architectural models are based on specific combinations of stem characters such as rhythms of growth and branching, tropisms or uprighting mechanisms and position of the inflorescence. Architectural models are more easily identifiable in young trees, before reiteration occurs. Architectural analysis may be relatively simple, for example when treating with “monopodial trees” of equatorial forests.
To investigate the influence of multiple canopy openings on the composition and diversity of recruited saplings in a forest frequently disturbed by typhoons. We conducted tree‐by‐tree censuses (diameter at breast height ≥ 1 cm) and mapped gaps (canopy height < 5 m) in 1993, 2000, 2008, and 2013 in a tropical mountain zonal foothill evergreen broad‐leaved forest in Nanjenshan Nature Reserve, Taiwan. We analyzed the composition and diversity of recruited saplings within a 2.1 ha plot (840 sampling quadrats (5 m × 5 m)) with variable numbers of canopy openings recorded during the study period. Composition of recruited saplings was dissimilar between quadrats that stayed opened and those that stayed closed throughout the study period (pairwise similarity estimates C02 = 0.52, 95% CI = 0.38–0.66). The quadrats under closed canopy had high diversity when weighting rare species (species richness), whereas quadrats with one or two gap opening records during the past 20 years had high diversity when weighting the abundance of species. Although canopy openings provided establishment conditions for saplings of some shade‐intolerant species, due to the nature of small gap size, such habitats do not favor the dominance of shade‐intolerant species. Even in a frequently disturbed forest, species composition and richness of recruited saplings were mainly contributed by shade‐tolerant species. Although multiple canopy openings facilitated the establishment of shade‐intolerant species, species diversity in the study forests is possibly mainly mediated by coexistence mechanisms of those shade‐tolerant species rather than light‐gap‐related species strategies. In a forest frequently disturbed by typhoons, forest canopies can have multiple times of openings. Quadrats (5 m × 5 m) that stayed opened (Type‐4) and those that stayed closed (Type‐0) throughout the 20‐year study period had dissimilar density and composition of recruited saplings, especially the shade‐intolerant species. However, species diversity of recruited saplings in the study forests was likely to be contributed by the mechanisms related to the dominant shade‐tolerant species, rather than light‐gap mediated species strategies due to the nature of small gaps in the study forest.
Coffea canephora has two botanical varieties, Robusta and Conilon. Intraspecific variability was hypothesized and projected for the selection of C. canephora plants able to maintain production in the context of global climate changes. For that, architectural, C-assimilation and biomass analyses were performed on 17-month-old Robusta (clones ‘A1’ and ‘3 V’) and Conilon (clones ‘14’ and ‘19’) varieties grown in non-limiting soil, water, and mineral nutrient conditions. Nondestructive coffee plant architecture coding, reconstruction, and plant photosynthesis estimations were performed using a functional-structural plant modeling platform OpenAlea. 3D reconstructions and inclusion of parameters calculated and estimated from light response curves, such as dark respiration (Rd), maximum rate of carboxylation of RuBisCO, and photosynthetic electron transport allowed the estimation of instantaneous and daily plant photosynthesis. The virtual orchard leaf area index was low, and light was not a limiting factor in early C. canephora development stages. Under such conditions, Robusta assimilated more CO2 at the plant and orchard scale and produced higher total biomass than Conilon. Lower plant daily photosynthesis and total biomass were correlated to higher Rd in Conilon than in Robusta. Among the architectural traits, leaf inclination, size, and allometry were most highly correlated with plant assimilation and biomass. Relative allocation in leaf biomass was higher in ‘19’ Conilon than in young Robusta plants, indicating intraspecific biomass partitioning. Similarly, variation in relative distribution of the root biomass and the root volume reflected clonal variation in soil occupation, indicating intraspecific variability in space occupation competitiveness. C. canephora denoted high root allocation in both Conilon and Robusta clones. However, relevant differences at sub-specific levels were found, indicating the high potential of C. canephora to cope with drought events, which are expected to occur more frequently in the future, due to climate changes. The methodology developed here has the potential to be used for other crops and tree species.
Young trees (saplings) of the Norway spruce (Picea abies [L.] Karst.) regenerating populations were analysed on 7 plots in the Šumava Mts. (Bohemian Forest), on 5 plots in the Jeseníky Mts. (Eastern Sudetes), and 1 plot in the Krkonoše (Giant Mts.). All 13 plots were located at the forest altitudinal (vegetation) zones of natural Picea abies stands. Each selected tree was characterized by microscopic features of the first-year needles. The free-hand needle cross-sections were prepared from three needles of each tree and measured by digital microphotos. The following needle characteristics were measured: width, thickness, and vascular bundle diameter. Each population was described by variability of these parameters. Populations were classified based on the data set. Two artificially planted populations were most different. Populations resulting in natural stands have different phenotype variability, possibly as a result of the parent stand history: two extreme examples are Eustaška locality (Jeseníky Mts.) with no known disturbance, and Trojmezí locality (Šumava Mts.), where wind and bark beetle disturbances were repeatedly recorded.
Premise:
Root-sprouting (RS) is an evolutionary independent way how a plant attains its architecture, alternative to axillary stem branching. RS plants are better adapted to disturbance than non-RS plants, and the vigour of RS is frequently boosted by biomass removal. Nevertheless, RS plants are rarer than plants that are not capable of RS - possibly because they must overcome developmental barriers such as intrinsic phytohormonal balance or because RS ability is conditioned by injury to the plant body. The objective of this study was to identify what is behind the ability of RS: phytohormones or injury?
Methods:
In a greenhouse experiment, growth parameters, root respiration and phytohormones were analysed in two closely related clonal herbs that differ in RS ability (spontaneously RS Inula britannica and rhizomatous non-RS I. salicina) either exposed to severe biomass removal or not.
Results:
We confirmed RS ability in the previously reported RS species I. britannica; however, RS ability was not boosted by injury. While root respiration did not differ between the two species and decreased continuously with time irrespectively of injury, phytohormone profiles differed significantly. In RS species, the auxins-to-cytokinins ratio was low and injury further decreased it.
Conclusions:
Our study represents the first attempt to test drivers behind different plant growth forms and suggests that intrinsic phytohormone regulation, especially the auxins-to-cytokinins ratio, might be behind RS ability. Injury - causing phytohormonal imbalance - seems to be less important in spontaneously RS species than it has been expected for RS species in general. This article is protected by copyright. All rights reserved.
Background: The subtropical dune thicket (hereafter "dune thicket") of the Cape Floristic Region experiences a wide range of fire exposure throughout the landscape, unlike other dry rainforest formations that rarely experience fire. We sought to determine how fire exposure influences species composition and the architectural composition of dune thicket.
Methods: We used multivariate analysis and diversity indices based on cover abundance of species to describe the species composition, architectural guild composition and structure of dune thicket sites subject to different levels of fire exposure, namely low (fire return interval of >100 years), moderate (fire return interval of 50-100 years), and high (fire return interval of 10-50 years).
Results: The diversity, cover abundance and architectural guild cover abundance of dune thicket canopy species were strongly influenced by the level of fire exposure such that each level was associated with a well-circumscribed vegetation unit. Dune thickets subject to low fire exposure comprises a floristically distinct, low forest characterized by shrubs with one-to-few upright stems (ca. 4-8 m tall) and a relatively small canopy spread (vertical growers). Of the 25 species in this unit, 40% were restricted to it. Dune thickets subject to moderate fire exposure had the highest abundance of lateral spreaders, which are multi-stemmed (ca. 3-6 m tall) species with a large canopy spread and lower stature than vertical growers. None of the 17 species found in this unit was restricted to it. Dune thickets subject to high fire exposure had the highest abundance of hedge-forming shrubs, these being low shrubs (ca. 0.6-1.4 m tall), with numerous shoots arising from an extensive system of below-ground stems. Of the 20 species in this unit, 40% were restricted to it. Multivariate analysis identified three floristic units corresponding to the three fire exposure regimes. Compositional structure, in terms of species and architectural guilds, was most distinctive for dune thickets subject to high and low fire exposure, while the dune thicket subject to moderate fire exposure showed greatest compositional overlap with the other units.
Conclusion: Fire exposure profoundly influenced the composition and structure of dune thicket canopy species in the Cape Floristic Region. In the prolonged absence of fire, the thicket is invaded by vertical-growing species that overtop and outcompete the multi-stemmed, laterally-spreading shrubs that dominate this community.
A review of the fossil record coupled with insights gained from molecular and developmental biology reveal a series of body plan transformations that gave rise to the first land plants. Across diverse algal clades, including the green algae and their descendants, the plant body plan underwent a unicellul ar $\to$ colonial $\to$ simple multicellular $\to \,\,$complex multicellular transformation series. The colonization of land involved increasing body size and associated cell specialization, including cells capable of hydraulic transport. The evolution of the life-cycle that characterizes all known land plant species involved a divergence in body plan phenotypes between the haploid and diploid generations, one adapted to facilitate sexual reproduction (a free-water dependent gametophyte), and another adapted to the dissemination of spores (a more water-independent sporophyte). The amplification of this phenotypic divergence, combined with indeterminate growth in body size, resulted in a desiccation-adapted branched sporophyte with a cuticularized epidermis, stomates, and vascular tissues. Throughout the evolution of the land plants, the body plans of the sporophyte generation involved "axiation," i.e., the acquisition of a cylindrical geometry and subsequent organographic specializations.
The ecological relevance of early ontogenetic trends in root/shoot covariation in herbaceous plants is barely known. In the present study, this issue was tackled for seedlings and juvenile plants of two herbaceous species (Plantago lanceolata and Sanguisorba minor) that share several life-history traits and habitats. We measured root and shoot traits of plants growing in the same conditions. Plantago lanceolata plants develop shallow roots and increase biomass allocation to lateral roots through ontogeny. Sanguisorba minor plants form deeper root systems in which biomass allocation to the tap root increases through ontogeny. Root dry matter content was lower in the latter species. Shoot growth of P. lanceolata was linked to the biomass of lateral roots and to the biomass and morphology of the tap root whereas aboveground growth of S. minor was linked to the exploration capacity of the tap root. The number of internodes was linked to the number of first order lateral roots in the seedlings of both species, and also in juvenile plants of P. lanceolata. Specific leaf area was positively correlated with the specific length of the tap root only in S. minor; the dry matter contents of leaves and lateral roots were positively correlated in P. lanceolata. The contrasting patterns of biomass allocation of both species are linked to specific morphological and functional root-architecture traits, and could reflect different strategies of resource acquisition and soil exploration and exploitation. Plant species whose architectural features and habitats are broadly similar may differ in the way root and shoot traits relate to each other through ontogeny, thereby revealing unequal resource-use strategies.
CE TRAVAIL ANALYSE LE MODE DE FLORAISON DE QUELQUES PLANTES TROPICALES, HERBACEES ET LIGNEUSES, ESSENTIELLEMENT ORIGINAIRES DE GUYANE FRANCAISE. IL MONTRE QU'AU COURS DES DIFFERENTES ETAPES QUI JALONNENT LA VIE D'UNE PLANTE, LA REPARTITION DES INFLORESCENCES EST TRES PRECISE. LA FLORAISON N'APPARAIT QU'APRES L'ACQUISITION PAR LA PLANTE D'UN CERTAIN SEUIL DE DIFFERENCIATION. PAR LA SUITE, LA FLORAISON DEVIENT PLUS ABONDANTE, ET TEND A OCCUPER UN NOMBRE DE SITES CROISSANT AVEC LE DEVELOPPEMENT DE L'ORGANISME. CET ENVAHISSEMENT PAR LA FLORAISON TRADUIT UNE EVOLUTION COMMUNE A TOUTES LES ESPECES ETUDIEES. PARTANT DE CETTE APPROCHE ARCHITECTURALE DES PLANTES TROPICALES, LA FLORAISON EST INTERPRETEE COMME UNE ETAPE DU MOUVEMENT MORPHOGENETIQUE PARCOURU PAR LA PLANTE DE LA GERMINATION A LA MORT, ET LE CONCEPT DE FLORAISON AUTOMATIQUE EST PROPOSE
Annonaceae is a major pantropical family with 113 genera and about 2550 species. Cameroon is one of the most biodiverse countries in Africa but its flora remains incompletely known. In this volume of the Flora of Cameroon, we describe 166 native taxa representing 163 species in 28 native genera within the family Annonaceae. A total of 22 species (about 13%) are endemic to the country. We provide keys to all native genera, species, and infraspecific taxa. For each species a detailed morphological description and a map of its distribution in Cameroon are provided. Distribution maps and diversity analyses are based on a taxonomically verified database of 2073 collections. Across Africa, Cameroon is a center of diversity for Annonaceae harboring one of the highest numbers of species and genera. For example, Cameroon harbors the highest number of African species for the only pantropical genus of Annonaceae, Xylopia . Annonaceae are found across all 10 administrative regions of Cameroon but diversity is concentrated within the tropical rain forest areas situated in the south and South-West. The areas around Bipindi and Mount Cameroon show the highest levels of diversity, but this is correlated with collection effort. Line drawings and/or photographs accompany most species. One species new to science Uvariopsis etugeana Dagallier & Couvreur sp. nov. is described. We also undertake a number of nomenclatural changes such as lectotypifications, six new synonymies and two new combinations ( Uvaria anisotricha (Le Thomas) Couvreur, comb. nov. ; Uvariodendron fuscum var. giganteum (Engl.) Dagallier & Couvreur, comb. nov. ).
We used destructive sampling to assess ¹⁴ C‐calibrated age and growth of five individuals of Oenocarpus bataua from 7.35 to 21.6 m of total height. The largest individual was 59‐year‐old. Age decreased from the collar to the top of the aboveground stem and was positively correlated with number of leaf‐scars and height.
Abstract in Portuguese is available with online material.
A tubular survey of ant-plant symbioses worldwide summarizes aspects of the evolutionary ecology of these associations. Remarkable similarities between ant-plant symbioses in disjunct tropical regions result from convergent and parallel evolution of similarly preadapted ants and plants. Competition among ants has driven evolutionary specialization in plant-ants and is the principal factor accounting for parallelism and convergence. As habitat specialization accompanied the evolutionary radiation of many myrmecophytes, frequent host shifts and de novo colonizations by habitat-specific ants both inhibited species-specific coevolution and co-cladogenesis. and magnified the diversity of mutualistic partners.
The comparatively high species diversity of neotropical plant-ants and myrmecophytes probably results from two historical factors. Most importantly, influenced by Andean orogeny, greater habitat disturbance by fluvial systems has created a mosaic of habitat types unparalleled in other tropical regions; both myrmecophytes and plant-ants have diversified across habitat boundaries. Second, the arrival of a new wave of dominant ants (especially Crematogaster) may have condensed the diversity of relatively timid plant-ants to a greater degree in Africa and Asia than in the more isolated Neotropics. Regular trajectories in the evolutionary histories of plant-ants appear to be driven principally by competition, in a manner analogous to the taxon cycles or pulses proposed for other
groups.
Effect of neighbor tree competition on crown shape of Korean pine plantation in Northeast China was studied. A total of 48 trees aged 7–58 years were felled, and all living branches were measured. A novel neighbor competition index that considered the overlap length between subject tree and neighbor tree crowns was created and incorporated into crown shape model. The effects of neighboring competition on crown shape, largest crown radius, and inflection point were analyzed. A dummy variable approach was used to detect crown asymmetry. The crown length index (CLI) of the subject tree was selected as the best neighbor competition index, and the mean square error reduction compared with that of the basic model was 2.0% after incorporating CLI. Crown radius displayed differences in the four cardinal directions and followed the order north > west > south > east. The crown radius in four directions for different ages decreased with increasing CLI and the difference increased with increasing tree age. The competition index, which considers horizontal and vertical competition effects, can significantly improve the performance of crown shape model. Both of inflection point and largest crown radius increased with increasing of CLI; however, the Pearson correlation coefficient was not significant (P > 0.05).
Crucial for the climate adaptation of trees is a xylem anatomical structure capable of adjusting to changing water regimes. While species comparisons across climate zones have demonstrated anatomical change in response to altered water availability and tree height, less is known about the adaptability of tree vascular systems to increasing water deficits at the intraspecific level. Information on the between-population and within-population variability of xylem traits helps assessing a species’ ability to cope with climate change.
We investigated the variability of wood anatomical and related hydraulic traits in terminal branches of European beech (Fagus sylvatica L.) trees across a precipitation gradient (520—890 mm yr−1) and examined the influence of climatic water balance (CWB), soil water capacity (AWC), neighborhood competition (CI), tree height, and branch age on these traits. Further, the relationship between xylem anatomical traits and embolism resistance (P50) was tested.
Within-population trait variation was larger than between-population variation. Vessel diameter, lumen-to-sapwood area ratio and potential conductivity of terminal branches decreased with decreasing CWB, but these traits were not affected by AWC, while vessel density increased with an AWC decrease. In contrast, none of the studied anatomical traits were influenced by variation in tree height (21—34 m) or CI. Branch age was highly variable (2—22 years) despite equal diameter and position in the flow path, suggesting different growth trajectories in the past. Vessel diameter decreased, and vessel density increased, with increasing branch age, reflecting negative annual radial growth trends. While vessel diameter was not related to P50, vessel grouping index and lumen-to-sapwood area ratio showed a weak, though highly significant, positive relationship to P50.
We conclude that the xylem anatomy of terminal tree-top branches in European beech is modified in response to increasing climatic aridity and/or decreasing soil water availability, independent of a tree height effect.
Here, we provide an assessment of the variation in both vegetative and reproductive characters within the Melastomataceae, including the subfamilies Olisbeoideae, Kibessioideae, and Melastomatoideae, and the many tribes recognized within the last few decades: an extremely large and diverse clade. These morphological and vegetative anatomical characters are discussed, with special reference to their taxonomic significance and correlation with phylogenetic patterns within the family. Examples of both highly homoplasious or phylogenetically significant characters are presented, and, in general, infrafamilial clades are diagnosed mainly by character combinations, especially those recognized at a tribal or generic rank. Exceptional variation is seen in hair morphology, androecium/stamen form, and ovary position.
Intraindividual epigenetic mosaicism is probably widespread among long‐lived plants, yet its ecological significance as a potential source of variation in fitness‐related traits in plant populations remains virtually unexplored. This paper examines the hypothesis that extant epigenetic variation within plants can have both current and transgenerational fecundity correlates which could eventually translate into fitness variations among different parts of the same individual and their respective offspring.
Five modules, each consisting of a terminal branchlet bearing one inflorescence and its subtending leaves, were collected from each of 15 wild‐growing Lavandula latifolia (Lamiaceae) plants. They were characterized epigenotypically by the methylation state of methylation‐sensitive amplified fragment length polymorphism (MS‐AFLP) markers, and phenotypically by fecundity‐related traits (inflorescence length, and size, number and mass of seeds produced). Seeds from the different modules were sown in the greenhouse and resulting ‘subprogenies’ characterized phenotypically (germination probability and time to emergence, seedling size, susceptibility to fungal disease).
All plants sampled were internally heterogeneous with regard to the methylation state of 1%–13% of MS‐AFLP markers. Predictable relationships were found between epigenotypic and phenotypic variation across the extant modules of individual L. latifolia shrubs. Phenotypes of subprogenies from different modules of the same plant grown under homogeneous conditions in the greenhouse were predictably related to the epigenotype of the maternal module which produced the seeds.
Synthesis. The variable epigenotypes of different modules in the same plant not only predicted extant phenotypic variation among the modules themselves, but also phenotypic differences among the subprogenies produced by different modules. These relationships linking intraplant epigenotypic mosaicism with both extant and transgenerational heterogeneity in fitness‐related traits support the ‘epigenetic mosaicism hypothesis’ for plant variation, and also suggest hitherto unexplored ecological consequences of epigenotypically enhanced variation in the context of plant populations and communities.
Spruces (Picea spp.) are coniferous trees widespread in boreal and mountainous forests of the northern hemisphere, with large economic significance and enormous contributions to global carbon sequestration. Spruces harbor very large genomes with high repetitiveness, hampering their comparative analysis. Here, we present and compare the genomes of four different North American spruces: the genome assemblies for Engelmann spruce (Picea engelmannii) and Sitka spruce (P. sitchensis) together with improved and more contiguous genome assemblies for white spruce (P. glauca) and for a naturally occurring introgress of these three species known as interior spruce (P. engelmannii × glauca × sitchensis). The genomes were structurally similar, and a large part of scaffolds could be anchored to a genetic map. The composition of the interior spruce genome indicated asymmetric contributions from the three ancestral genomes. Phylogenetic analysis of the nuclear and organelle genomes revealed a topology indicative of ancient reticulation. Different patterns of expansion of gene families among genomes were observed and related with presumed diversifying ecological adaptations. We identified rapidly evolving genes that harbored high rates of nonsynonymous polymorphisms relative to synonymous ones, indicative of positive selection and its hitchhiking effects. These gene sets were mostly distinct between the genomes of ecologically contrasted species, and signatures of convergent balancing selection were detected. Stress and stimulus response was identified as the most frequent function assigned to expanding gene families and rapidly evolving genes. These two aspects of genomic evolution were complementary in their contribution to divergent evolution of presumed adaptive nature. These more contiguous spruce giga‐genome sequences should strengthen our understanding of conifer genome structure and evolution, as their comparison offers clues into the genetic basis of adaptation and ecology of conifers at the genomic level. They will also provide tools to better monitor natural genetic diversity and improve the management of conifer forests.
The Pleurophyllum clade is one of two main clades within subtribe Celmisiinae (Astereae) and includes 10 species almost entirely restricted to New Zealand (one species also occurs in the Australian Macquarie Islands), with seven of them confined to Stewart Island/Rakiura and the outlying Chatham and subantarctic islands. The clade is defined by its purple to dark red cyathiform disc corollas, which are absent from the other members of Celmisiinae. A new generic taxonomy of the clade is presented here with the recognition of three genera: Pleurophyllum with three species, Damnamenia (monotypic), and Macrolearia , a new genus segregated from Olearia , which is described here to accommodate the six species and one hybrid previously known as the “macrocephalous olearias.” The main morphological differences between the three genera lie in the growth form, trichome types of leaves and disc corollas, morphology of the style branches, presence/absence of staminodes, and cypselae morphology. These morphological differences are also discussed within subtribe, tribe, and family contexts, and special consideration is given to the use of the “megaherb growth form” concept for Pleurophyllum . The allopatric distribution of the three recognized genera is also stressed. Seven new combinations: Macrolearia angustifolia , Macrolearia oporina , Macrolearia semidentata , Macrolearia chathamica , Macrolearia colensoi , Macrolearia lyallii , and Macrolearia × traillii , and five new synonyms are proposed, and four names are lectotypified. Taxonomic keys are provided for genera and species.
ResearchGate has not been able to resolve any references for this publication.