Genome size is not related to life-history traits in primates.

Genome size (C value, the haploid DNA content of the nucleus) varies widely among eukaryotes, increasing through duplication or insertion of transposable elements and decreasing through deletions. Here, we investigate relationships between genome size and life-history attributes potentially related to fitness, including body mass, brain mass, gestation time, age at sexual maturity, and longevity, in 42 species of primates. Using multivariate and phylogenetically informed analyses, we show that genome size is unrelated to any of these traits. Genome size exhibits little variation within primates and its evolution does not appear to be correlated with changes in life-history traits. This further indicates that the phenotypic consequences of variation in genome size are dependent on the particular biology of the group in question.     

Toward a causal explanation of plant invasiveness: seedling growth and life-history strategies of 29 pine (Pinus) species

We studied 29 pine (Pinus) species to test the hypothesis that invasive species in disturbed habitats have distinct attributes. Seedling relative growth rate (RGR) and measures of invasiveness were positively associated across species as well as within phylogenetically independent contrasts. High RGR, small seed masses, and short generation times characterize pine species that are successful invaders in disturbed habitats. Discriminant analysis and logistic regression revealed that RGR was the most significant factor among these life-history traits separating invasive and noninvasive species. We also explored the causes of differences in RGR among invasive and noninvasive species. While net assimilation rate, leaf mass ratio, and specific leaf area (SLA) were all found to be contributing positively to RGR, SLA was found to be the main component responsible for differences in RGR between invasive and noninvasive pines. We investigated differences in SLA further by studying leaf anatomy, leaf density, and leaf thickness. We also evaluated relative leaf production rate as an important aspect of SLA. We proposed a hypothetical causal network of all relevant variables.     

Strategy Space and the Disturbance Spectrum: A Life-History Model for Tree Species Coexistence

The disturbance spectrum consists of disturbance patterns differing in type, size, intensity, and frequency. It is proposed that tree life-history traits are adaptations to particular disturbance regimes. Four independent axes are proposed to define the dominant dimensions of tree strategy space: shade tolerance, tree height, capacity for vegetative reproduction, and seed dispersal distance. A fitness model was developed to elucidate interactions between the proposed life-history traits. The model shows how alternate life-history sets can coexist when disturbance patterns fluctuate in space and time. Variable disturbance regimes were shown, based on data and simulation results, to enhance species coexistence, as predicted. The strategy space model accurately predicts the number of common tree species for the eastern United States, boreal Canada, and southwestern pi?on-juniper woodlands. The model also provides an explanation for latitudinal gradients in tree species richness in North America and Europe. The proposed model predicts a relationship between disturbance characteristics and the species composition of a forest that allows for the coexistence of large numbers of species. The life-history traits of size, growth rate, life span, shade tolerance, age of reproduction, seed dispersal distance, and vegetative reproduction are all incorporated into the model.     

不同生活型被子植物功能性状与基因组大小的关系

基因组大小在被子植物物种之间存在着巨大的变异, 但目前对不同生活型被子植物功能性状与基因组大小的关系缺乏统一的认识。本研究基于被子植物245科2,226属11,215个物种的基因组大小数据, 探讨了不同生活型物种种子重量、最大植株高度和叶片氮、磷含量4个功能性状与基因组大小之间的关系。结果表明, 被子植物最大植株高度和种子重量与基因组大小间的关系在草本和木本植物中存在显著差异。草本植物最大植株高度与基因组大小的关系不显著, 但种子重量与其呈极显著的正相关关系。木本植物最大植株高度与基因组大小显著负相关, 但种子重量与其关系不显著。木本植物叶片氮含量与基因组大小呈显著正相关, 但其他生活型植物的叶片氮、磷含量与基因组大小均无显著相关性。本研究表明被子植物功能性状与基因组大小的相关性在不同生活型间存在差异, 这为深入研究植物多种功能性状和植物生活型与基因组大小的权衡关系在植物演化和生态适应中的作用提供了重要依据。     

Reserve mass and dispersal investment in relation to geographic range of plant species: phylogenetically independent contrasts

Recent studies have reported conflicting evidence about correlations between seed size and plant species geographic range sizes. Using phylogenetically independent contrasts (PICs) within genera, we found no consistent differences in reserve mass between species with similar dispersal morphology and «wide>> versus «narrow>> geographic ranges. There was also no tendency within genera for broad ranged species to be those that allocate a larger percentage of the resources invested in each diaspora to dispersal structures. PICs were also constructed between species having a tenfold difference in seed size. In these PICs, the larger seeded species often occupied a greater number of regions than species with smaller seed sizes. This result was generated primarily through the comparison of species from different genera, families or higher level taxa which differed not only in seed mass but also in dispersal modes and growth forms. Finally, comparing species within Acacia and Eucalyptus having similar seed size but different dispersal modes, we found that bird dispersal (in Acacia ) and possession of a wing for wind dispersal (in Eucalyptus ) was associated with wider geographic range compared to lower-investment dispersal modes. Taken together, these comparisons indicate that seed size is not itself important as a factor influencing breadth of geographic range. Dispersal mode and growth form may have an influence, however, and seed size differences may be associated with contrasts in dispersal mode or growth form.     

The effect of genome size on detailed species traits within closely related species of the same habitat

In spite of the large number of studies on genome size, studies comparing genome size and growth‐related traits across a wider range of species from the same habitat, taking into account species phylogeny, are largely missing. I estimated the relationship between genome size and different seed and seedling traits in perennial herbs occurring in dry calcareous grasslands in northern Bohemia, Czech Republic. There was no relationship between genome size and plant traits in simple regression analyses, but several strong relationships emerged in analyses based on pairwise phylogenetically independent contrasts. There was a significant relationship between monoploid genome size and production of above‐ground biomass, seedling establishment success and seed weight and between holoploid genome size and seed dormancy. Because the results are based on phylogenetically independent contrasts over a range of species from the same type of habitat, they allow me to conclude that these patterns were not because of species group or habitat type, but really show a correlation with genome size. In contrast to previous studies, I found a higher number of relationships with monoploid than with holoploid genome size. This may be because the traits observed in this study are directly related to plant growth and thus to life‐cycle time, which is determined by monoploid genome size. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160 , 290–298.     

Ecological effects of cell-level processes: genome size,functional traits and regional abundance of herbaceous plant species

Background and Aims

Genome size is known to be correlated with a number of phenotypic traits associated with cell sizes and cell-division rates. Genome size was therefore used as a proxy for them in order to assess how common plant traits such as height, specific leaf area and seed size/number predict species regional abundance. In this study it is hypothesized that if there is residual correlation between genome size and abundance after these traits are partialled out, there must be additional ecological effects of cell size and/or cell-division rate.

Methods

Variation in genome size, plant traits and regional abundance were examined in 436 herbaceous species of central European flora, and relationships were sought for among these variables by correlation and path analysis.

Key Results

Species regional abundance was weakly but significantly correlated with genome size; the relationship was stronger for annuals (R² = 0·145) than for perennials (R² = 0·027). In annuals, genome size was linked to abundance via its effect on seed size, which constrains seed number and hence population growth rate. In perennials, it weakly affected (via height and specific leaf area) competitive ability. These relationships did not change qualitatively after phylogenetic correction. In both annuals and perennials there was an unresolved effect of genome size on abundance.

Conclusions

The findings indicate that additional predictors of regional abundance should be sought among variables that are linked to cell size and cell-division rate. Signals of these cell-level processes remain identifiable even at the landscape scale, and show deep differences between perennials and annuals. Plant population biology could thus possibly benefit from more systematic use of indicators of cell-level processes.     

Relative growth rate and biomass allocation in 20 Aegilops (Poaceae) species

This paper analyses relationships between relative growth rate ( rgr ), seed mass, biomass allocation, photosynthetic rate and other plant traits as well as habitat factors (rainfall and altitude) in 20 wild species of Aegilops L. and one closely related species of Amblyopyrum (Jaub. & Spach) Eig., which differ in ploidy level (diploid, tetraploid and hexaploid). The plants were grown hydroponically for 20 d in a growth chamber. The relationships between parameters were calculated either using the phylogenetic information (phylogenetically independent contrasts, PIC) or without using the phylogenetic information (trait values of taxa, TIP). The results using the two approaches were very similar, but there were a few exceptions in which the results were different (e.g. rgr vs. seed mass). Specific leaf area ( sla ) was positively correlated with leaf area ratio ( lar ) and negatively correlated with net assimilation rate ( nar ), which together resulted in the absence of a correlation between sla and rgr . Leaf photosynthetic rates (expressed on a mass or area basis) showed no correlation with rgr . rgr was positively correlated with the stem mass ratio and negatively with root mass ratio. Species with a lower d. wt percentage have a higher rgr . Aegilops species from locations with higher annual rainfall invested less biomass in roots and more in shoots (leaves and stems) and had a higher rgr . Diploid species had a lower seed mass and initial mass than the hybrids (tetraploid and hexaploid species), but there was no correlation of rgr with ploidy level. Polyploid species, which have higher seed mass, occur at a higher altitude than diploid species. Our results show that variation in rgr in Aegilops and Amblyopyrum spp. is associated mainly with variation in biomass allocation (proportion of biomass in stems and roots) and d. wt percentage, and not with variation in sla , leaf photosynthetic rates or seed mass.     

Functional traits associated with plant colonizing and competitive ability influence species abundance during secondary succession: Evidence from subalpine meadows of the Qinghai–Tibetan Plateau

It is widely recognized that colonists and competitors dominate early and late succession, respectively, with selected species having different colonizing and competitive abilities. However, it remains unknown whether colonizing and competitive ability can determine species abundance directly over succession. The data for five key functional traits were collected (photosynthesis rate, leaf turgor loss point, leaf proline content, seed mass, and seed germination rate), which are direct indicators of plant competitive and colonizing abilities including growth, drought and cold stress resistance, dispersal, and seed dormancy. Here, we tested the effects of colonizing and competitive abilities on species abundance, by employing a linear mixed‐effects model to examine the shifts in the relationship between species abundance and these five colonization and competition‐related traits in species‐rich subalpine secondary successional meadows (at 4, 6, 10, 13 years of age, and undisturbed, respectively) of the Qinghai–Tibetan Plateau. The abundant species at the early‐successional meadows tend to have high photosynthetic rate, high leaf proline content, low seed mass, and seed germination rate for having high colonizing ability, but low competitive ability. By contrast, late‐successional communities tend to be dominated by species with high competitive ability, but low colonizing ability, indicated by large seeds, high seed germination rate, low photosynthetic rate, and leaf proline content. The observed directional shifts in the relationships between traits (photosynthetic rate, leaf proline content, seed mass, and seed germination rate) and abundance with successional age, bring two new understandings of community assembly during succession of subalpine meadows in the Qinghai–Tibetan Plateau. First, it discloses that the differences in species abundance over succession can be directly attributed to differences in colonizing and competitive abilities of different species. Second, it expands the effects of multiple life historical differences including growth, resource competitive ability, cold stress resistance, dispersal, and seed germination strategy, represented by functional traits on community assembly along succession, that is, from the species to the community level.     

Differential seed germination responses to the ratio of red to far-red light in temperate and tropical species

Variation in vegetation density creates a range of red to far-red ratios of irradiance (R:FR) potentially permitting fine-scale discrimination of light conditions for seed germination. However, remarkably few studies have explored whether R:FR responses of germination vary among species that differ in distribution and life-history traits. In this study, we explored the relationships between R:FR requirements and four species characteristics: seed mass, latitudinal distribution (tropical vs. temperate), seed dormancy (dormant vs. nondormant), and plant growth form (woody vs. nonwoody). We obtained data on germination response to R:FR of 62 species from published literature and added new data for ten species from aseasonal tropical forests in Borneo. First, we analyzed whether species characteristics influenced overall light dependency of germination using phylogenetic logistic regression. We found that seed mass had a strong negative effect on light dependency, but that the seed mass at which tropical taxa had a 50 % probability of light dependency was 40 times that of temperate taxa. For light-dependent species, we found that the threshold R:FR that stimulates 50 % of maximum germination (R:FR₅₀) was also related to seed mass and latitudinal distribution. In agreement with an earlier study, we found that for temperate taxa, the R:FR₅₀ was significantly negatively correlated with seed mass. In contrast, for 22 tropical taxa, we found a significant positive correlation. These opposing relationships suggest contrasting selection pressures on germination responses of tropical taxa (mostly trees) and temperate herbaceous plants, and which are likely related to differences in seed longevity, seed burial rates, and reproductive output.     

Genome size scaling through phenotype space

Background and Aims: Early observations that genome size was positively correlatedwith cell size formed the basis of hypothesized consequencesof genome size variation at higher phenotypic scales. This scalingwas supported by several studies showing a positive relationshipbetween genome size and seed mass, and various metrics of growthand leaf morphology. However, many of these studies were undertakenwith limited species sets, and often performed within a singlegenus. Here we seek to generalize the relationship between genomesize and the phenotype by examining eight phenotypic traitsusing large cross-species comparisons involving diverse assemblagesof angiosperm and gymnosperm species. These analyses are presentedin order of increasing scale (roughly equating to the numberof cells required to produce a particular phenotypic trait),following the order of: cell size (guard cell and epidermal),stomatal density, seed mass, leaf mass per unit area (LMA),wood density, photosynthetic rate and finally maximum plantheight. Scope: The results show that genome size is a strong predictor of phenotypictraits at the cellular level (guard cell length and epidermalcell area had significant positive relationships with genomesize). Stomatal density decreased with increasing genome size,but this did not lead to decreased photosynthetic rate. At higherphenotypic scales, the predictive power of genome size generallydiminishes (genome size had weak predictive power for both LMAand seed mass), except in the interesting case of maximum plantheight (tree species tend to have small genomes). There wasno relationship with wood density. The general observation thatspecies with larger genome size have larger seed mass was supported;however, species with small genome size can also have largeseed masses. All of these analyses involved robust comparativemethods that incorporate the phylogenetic relationships of species. Conclusions: Genome size correlations are quite strong at the cellular levelbut decrease in predictive power with increasing phenotypicscale. Our hope is that these results may lead to new mechanistichypotheses about why genome size scaling exists at the cellularlevel, and why nucleotypic consequences diminish at higher phenotypicscales.     

种子重量的生态学研究进展

作为植物生活史中的一个关键性特征,种子重量与其它许多植物性状和生态因子有关,种子重量的分异与其它一些植物性状及环境的变化关系在进化生物学上已经成为一个非常有意义的研究内容,且具有一定的实践意义。种子重量被发现与下列的一些植物学和群落学性状有关:植物的生活型、种子的散布能力、种子的散布方式、植物的高度、植物的冠幅、植物的比叶面积、植物的寿命、动物的捕食、植被中植物的数量或多度、土壤中种子的数量或多度、种子的休眠、种子在土壤中的持久性和植物的净初级生产力等,另外生态因子如降雨、温度、坡向、海拔、经度、纬度、光强和干扰等都影响种子的重量。种子的重量被认为是在大量小种子和少量大种子之间的进化折衷,在一定的能量限度内,较大重量的种子一般具有较少的数量,而较小重量的种子一般数量较多,这是种子重量和数量方面具有的一种反向关系。与其它性状相比,很多研究都表明种子重量和植物的生活型的关系密切。没有散布结构或风散布的种子比以动物和水作为散布媒介的种子重量要小。种子重量与捕食的关系现发现有3种格局。种子重量和形状与种子在土壤中的持久性的关系有4种格局。在干旱和阴暗的环境条件下,种子有变大的趋势。大重量种子比小种子赋予幼苗较优势的竞争地位,其原理尚有争论,尚不清楚是否是幼苗阶段的竞争决定了世界上大部分植被类型的物种组成。未来的研究方向主要有以下几个方面:1) 种子重量与植物系统学相结合,探索种子重量的变化规律;2)调查群落三向(纬度、经度和海拔)性的种子重量谱变化规律;3) 群落演替与群落种子重量谱的变化;4) 种子重量与群落中植物个体和种子的数量的关系及机理研究;5) 微生境、微地形如坡向、坡位和林间隙等对种子重量的影响;6) 全球气候变化和种子重量变化的关系。     

Can population genetic structure be predicted from life-history traits?

Population genetic structure is a key parameter in evolutionary biology. Earlier comparative studies have shown that genetic structure depends on species ecological attributes and life-history traits, but species phylogenetic relatedness had not been accounted for. Here we reevaluate the relationships between genetic structure and species traits in seed plants. Each species is characterized by a set of life-history and ecological features as well as by its geographic range size, its heterozygote deficit, and its genetic structure at nuclear and organelle markers to distinguish between pollen- and seed-mediated gene flow. We use both a conventional regression approach and a method that controls for phylogenetic relationships. Once phylogenetic conservatism and covariation among traits are taken into account, genetic structure is shown to be related with only a few synthetic traits, such as mating system for nuclear markers and seed dispersal mode or geographic range size for organelle markers. Along with other studies on invasiveness or rarity, our work illustrates the fact that predicting the fate of species across a broad taxonomic assemblage on the basis of simple traits is rarely possible, a testimony of the highly contingent nature of evolution.     

Traits and ecological strategies of Australian tropical and temperate climbing plants

Aim Understanding large scale patterns in trait variation in climbing plants (lianas, vines, scramblers, twiners) is important for the development of a stronger theoretical understanding of climbing plant ecology and for more applied issues such as prediction of community assembly under changing climatic conditions. We compared values of five key functional traits for 388 species of climbing plant from tropical and temperate regions of Australia to quantify variation between these two biogeographic regions. Location Australia. Methods Data on dispersal mode, growth habit, leaf form, leaf size and seed mass were compiled from field measurements and published sources. Comparative analyses were performed in three ways: (1) across species where each species was treated as an independent data point, (2) using evolutionary divergence analyses for each trait, and (3) in multidimensional space using a matrix of similarities between species. Results Tropical climbing plants had 22‐fold greater seed mass and four times greater leaf size than did temperate species. Tropical climbers were more likely to be woody (63%) than were temperate species (40%). Surprisingly we found a similar proportion of animal‐dispersed seeds in the two regions, although we expected animal‐dispersed seeds to be more prevalent in the tropics. We also found similar proportions of simple‐ and compound‐leaved species between the two regions. All of our findings were consistent between cross‐species and phylogenetic analyses indicating that patterns in present‐day species are reflected in the evolutionary history of Australian climbers. Multivariate analyses suggested that there is a spectrum of variation among climbing plants, with tropical species having greater seed mass, leaf size and woody growth compared with temperate climbing plant species. Main conclusions Tropical and temperate climbers of Australia exhibit a mixture of similar and contrasting traits and ecological strategies. Understanding strategy variation along latitudinal gradients will be particularly informative for predicting ecosystem and community structure with climate change.     

Exploring the causes of variation in phenology and morphology in Mediterranean geophytes: a genus-wide study of Cyclamen

The phenology and morphology of Mediterranean plants are constrained by drought in summer and cold temperatures in winter. In this study we examine how climatic factors and phylogenetic constraints have shaped variation in the phenology and morphology of 17 species of the genus Cyclamen cultivated in uniform garden conditions. We quantify the extent to which traits differ among subgenera and thus represent conserved traits within evolutionary lineages. We also explore whether leaf, flowering and seed-release phenology are correlated among species, and thus whether variation in flowering phenology results from selection on dispersal phenology. Our results show a significant influence of subgenus membership on leaf and flowering phenology but not on morphological traits or the timing of seed release. Among-species variation in foliage height, leaf size and seed mass (but not in floral traits) is correlated with chromosome number. Leaf traits show that species with a shorter vegetative period have a higher capacity for resource acquisition. Major phenological shifts, i.e. spring vs. autumn flowering and a decoupling of leaf and flower phenology in autumnal flowering species, thus occurred prior to the diversification of species in each subgenus and not as a response to selection on dispersal timing. Leaf and flowering phenology illustrate a gradient of strategies from autumn flowering in the absence of leaves (hysteranthous species) to spring flowering with fully developed foliage (synanthous species). In the former, flowering is uncoupled from resource acquisition by simultaneous photosynthesis, indicative that hysteranthy is a response to temporal unpredictability in the onset of rain after the summer drought. Our results support the idea that whereas leaf development is controlled primarily by moisture availability and secondarily by temperature, flowering is temperature dependent, above a minimum moisture threshold. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society, 2004, 145 , 469–484.     

Age at maturity and diversification in woody angiosperms

Angiosperm diversification has been associated with plant-animal interactions such as seed dispersal and pollination and life-history characters such as rapid growth and fast reproduction. This paper relates a life-history character (age at maturity) to woody angiosperm diversification. Here I present a comparative analysis of data drawn from the literature, indicating that time to first reproduction is shorter in woody angiosperms than in gymnosperms. In addition, age at maturity is negatively correlated with the rate of diversification (measured as the number of species per genus) at all the taxonomic levels analyzed and also when phylogenetically independent contrasts were conducted. This correlation suggests that early reproduction promotes diversification in woody angiosperms. Furthermore, this correlation is not a confounding effect of the association between age at maturity and other ecological factors that promote angiosperm diversification, such as pollination and seed dispersal systems.     

Life-history traits are correlated with geographical distribution patterns of western European forest herb species

Aim To investigate whether six plant life‐history traits that have been related to colonization ability at local scales are also related to the geographical range characteristics of 273 forest plant species. Location Continental western Europe, five countries in particular: France, Luxemburg, Belgium, the Netherlands and Germany. The region is situated between 42° and 55°N and 5°W and 15°E and has a summed total area of 971,404 km². Methods Distribution data were compiled from five national data bases and converted to a 10′ grid. Life‐history traits were taken from existing compilations of autecological information of European species. The spatial arrangement of occupied grid cells was investigated using Ripley's K. Cross‐species correlations and phylogenetically independent contrasts were used to investigate the relationships between plant life‐history traits and three range characteristics: area of occupancy, latitudinal extent and centroid latitude. Results For herbaceous species, seed dispersal mode, seed production and seed bank longevity exhibited significant associations with geographical range characteristics, including area of occupancy. Woody plant species exhibited fewer significant associations, although maximum height was positively associated with range centroid latitude within the study area. Furthermore, the ranges of species with limited dispersal ability were found to be more clustered than the ranges of species with morphological adaptations for long‐distance seed dispersal. Main conclusions For western European forest plant species, life‐history traits that are related to colonization ability at local scales are associated with variation in large‐scale geographical range characteristics. This finding implies that the distributions of some forest plant species in the study area may be limited by seed dispersal and colonization capacity rather than climate or other environmental factors.     

外果皮厚度和种子大小对五种栎属橡子扩散的影响

动物对种子的扩散和贮藏是一个复杂的生态学过程,常常受到种子特征的影响。有关种子特征如何影响动物对种子扩散,许多研究结果并非完全一致。我们于2009 年9 月在黑龙江东方红林场野外和围栏内释放五种栎属橡子(Quercus mongolica,Q.serrata var. brevipetiolata,Q. aliena,Q.variabilis 和Q. liaotungensis),研究种子特征对鼠类(Apodemus peninsulae, Clethrionomys rufocanus 和Tamias sibiricus)扩散和埋藏橡子的影响。野外释放结果表明:橡子大小和外果皮厚度显著影响鼠类对橡子的扩散和埋藏。鼠类偏向扩散和埋藏种皮厚的大橡子,种皮薄的小橡子则多被原地取食。种皮厚的大橡子扩散距离显著高于种皮薄的小橡子。然而,只有外果皮的厚度显著影响围栏内花鼠对橡子的扩散和埋藏,橡子大小并非主要的影响因素。种子特征影响种子扩散的效应可能在种群和群落水平上存在差异。     

Phenology and fecundity in 11 sympatric pioneer species of Macaranga (Euphorbiaceae)in Borneo

Reproductive traits of tropical tree species vary predictably in relation to successional stage, but this variation may be due to the species' phylogenetic histories rather than selective pressures imposed by regeneration requirements. Reproductive phenology, tree size at the onset of reproduction, and fecundity of 11 sympatric, closely related Macaranga species were studied to investigate within-species variation in reproductive traits in relation to resource availability, and among-species variation in relation to other life-history traits (shade tolerance, seed size and maximum tree size, H(max)) and consequently the requirements for forest-gap colonization. Nine species reproduced in synchronous episodes, and two species reproduced continuously over 32 mo. Episodic reproduction was most intense in 1992 following a severe drought. For several species, reproductive trees had greater light availability, lower fecundity in lower light levels, and lower growth rates than nonreproductive trees, reflecting resource-limited reproduction. Among species, H(max) was negatively correlated with shade tolerance and seed size. Tree size at the onset of reproduction and fecundity was strongly linked to this axis of life-history variation, but phenological pattern was not. Absolute tree size at the onset of reproduction was positively correlated with H(max) and negatively correlated with shade tolerance. Relative size at reproductive onset was not correlated with shade tolerance or H(max). Fecundity ranged four orders of magnitude among species and was correlated positively with H(max) and negatively with seed size and shade tolerance. The interrelationships among these reproductive and other life-history traits are strongly correlated with the species' requirements for gap colonization.     

植物种子大小与幼苗生长策略研究进展

种子大小和幼苗更新对策是植物生活史策略的重要组成部分.本文从不同侧面综述了当前国内外关于种子大小和幼苗之间关系的生态学研究,包括:种子大小对萌发出土的影响,种子大小与幼苗形态生长特性之间的关系,种子大小与幼苗存活、竞争能力之间关系等,并对今后的相关研究进行了展望.在不同的微环境和植被类型下,种子大小与幼苗生长之间的关系可能有所差异;种子大小对植物幼苗生长的影响导致种子大小不同的植物对植被幼苗更新补充的贡献不同;种子大小与幼苗生活史策略关系在大尺度的群落空间水平上和小尺度的物种间与物种内的研究对于天然植被的更新恢复研究具有重要意义.