An Application of the Sex Allocation Theory to Arisaema serratum

Abstract The sex allocation theory based on size-specific demography is applied to sex change phenomena exhibited by Arisaema serratum , which changes sex expression according to its size. In the evolutionary analysis where adopted strategy correlates with resource level, identifying equal resource level is very important. But directly measured size does not seem to represent the plant's real resource level perfectly. In the analysis presented here, we introduce a new variable that represents the resource level. According to the sex allocation theory, we calculated the transition matrix and other demographic parameters, the stable sex-and-size distribution, and reproductive values. The obtained results were: (1) reproductive values generally increased in accordance with size, but in a different manner for different sexes; (2) in the size class where different sex expressions were adopted, reproductive values for the equal resources were the same; and (3) plant individuals seemed to adopt evolutionarily stable strategies. The adaptive nature of the plant is further discussed.     

三种同域分布喉毛花的繁殖分配

以青藏高原高寒草甸中三种同域分布的喉毛花为研究对象,通过比较三个种的植株性状和繁殖分配,探讨繁殖分配的种间差异及其与植株个体大小的关系。结果表明:(1)三个种的植株高度、顶花大小和单株花数目、繁殖分配均存在种间差异,这可能与其各自的交配系统和具体的生境以及相应的生活史对策有关;(2)在三种喉毛花中,投入到营养器官和繁殖器官的绝对资源量均呈显著正相关,未检测到植株生长和繁殖间的权衡关系;(3)三个种的个体大小与繁殖器官生物量均呈显著正相关,而与繁殖分配均呈显著负相关,这表明个体越大,繁殖投入越高,而繁殖分配越低,与以往研究结果一致,这可能是由于繁殖分配与个体大小之间存在异速关系。     

青藏高原不同生境下湿生扁蕾(Gentianopsis paludosa)个体大小依赖的繁殖分配

植物对资源的投资和分配是生态学中的重要问题,它反映了植物应对环境变化时的生活史策略。选择青藏高原东缘同一海拔下的嵩草草甸(Kobresia sp.meadow)、金露梅灌丛(Potentilla fruticosa shrub meadow)以及草甸-灌丛交错带3种生境类型,并以3种生境下的湿生扁蕾(Gentianopsis paludosa)为对象,研究了其繁殖分配特征。结果发现:(1)在种群水平上,在生境从草甸经交错带到灌丛的变化中,湿生扁蕾个体大小和繁殖分配比例逐渐增加;3个种群湿生扁蕾的总花数目没有显著差异,但草甸生境湿生扁蕾的蕾期花数目显著高于灌丛生境,而果期花数目则显著低于灌丛生境;(2)在个体水平上,湿生扁蕾的繁殖绝对投入与个体大小显著正相关,且各种群植株都存在繁殖所需的个体大小阈值,而繁殖阈值在生境从草甸经交错带到灌丛的过渡中逐渐减小;湿生扁蕾的繁殖相对投入与个体大小负相关,但相关系数随着生境从草甸经交错带到灌丛的过渡中逐渐减小;各种群花数目与湿生扁蕾植株个体大小显著正相关。研究表明,湿生扁蕾的繁殖投资存在大小依赖效应,但生境差异会对其繁殖投资和生活史策略造成显著影响,而这种影响主要是由不同生境下自然条件的不同造成的。同时,资源分配也与湿生扁蕾的遗传特性和延迟自交的繁育系统特征有关。湿生扁蕾这种不同生境下个体大小依赖的繁殖投资差异是湿生扁蕾与其生境长期适应和进化(生境选择)的结果。     

Altitudinal Variations in Reproductive Allocation of Bergenia purpurascens (Saxifragaceae)

The strategy of resource allocation between vegetative and reproductive functions, quantitative relationship between size and reproductive output are central aspects of plant life history. To test the tactics of resource allocation and its altitudinal trend, we examined the reproductive allocation (RA) of Bergenia purpurascens (Saxifragaceae), in six populations along a shady slope in Sejila Mountain of southeast Tibet, at an altitude gradient from 4 200 m to 4 640 m. Our results showed that (1) with increasing altitude, vegetative biomass, reproductive biomass, total aboveground biomass, flower number per plant and length of flower stalk decreased significantly, but the number of leaves did not change greatly. However, the change of RA did not show a monotonic trend when altitude increased, shifting from significantly decreasing below the tree line to slightly increasing above it; (2) vegetative biomass was positively correlated with reproductive biomass, but negatively correlated with RA in all populations, but the level of significance was different among the populations; (3) RA decreased with individual size in all populations, whereas the relationship between absolute resource allocated to reproduction and individual size was allometric; (4) reproductive allometry and a size threshold for reproduction did exist in this alpine perennial, but the obvious altitudinal trend was only found along the populations below the tree line, not above it. We then concluded the altitude could not fully explain the change of resource allocation strategy of this alpine perennial, and different effects of size and habitat on RA may result from various environmental constraints along the altitudinal gradient or genetic background. Therefore, each individual within a population will follow its own developmental trajectory shaped by its genotype and the habitats. The most innovative finding was plant adaptation and resource trade off might be sharply altered at the tree line, which is a sensitive area in alpine mountains. Further investigations are needed to better understand the relationship between the reproductive allocation and changing environmental conditions.     

岩白菜（虎耳草科）不同海拔居群的繁殖分配

资源分配策略是植物生活史研究的重要内容之一,植物用于繁殖的相对资源比例（即繁殖分配）与植株的生活史特征、个体大小及植株的生境密切相关。本文研究了藏东南色季拉山一个阴坡上海拔4200m～4640m范围内6个不同居群的虎耳草科多年生草本植物岩白菜（Bergenia purpurascens）的繁殖分配特征,结果发现：（1）繁殖器官生物量、营养器官生物量、地上部分总生物量、花数目、花序轴长度均随海拔的升高而显著降低,而叶数目随海拔变化不大,繁殖分配值则先降低后升高,转折点在林线过渡带（海拔4400m）处;（2）各居群（海拔4300m居群除外）营养器官生物量与繁殖器官生物量均显著正相关,而营养器官生物量与繁殖分配则负相关,但各居群的显著性不同;（3）各居群繁殖器官生物量与植株个体大小（营养器官生物量）呈不同程度的异速增长,而繁殖分配则与植株个体大小负相关;（4）各居群植株都存在一个繁殖所需的个体大小阈值,而且这一阈值在林线以下区域随海拔的升高而显著增大,在林线以上区域变化不显著。研究结果表明,海拔并不是影响岩白菜繁殖分配策略的唯一生态因子,不同居群的生境状况和植株个体大小都与其资源分配策略密切相关,高山地区林线的存在对植物资源的权衡方式会产生巨大影响。     

Allometry and development in herbaceous plants: functional responses of meristem allocation to light and nutrient availability

We examined the relationship between meristem allocation and plant size for four annual plant species: Arabidopsis thaliana, Arenaria serphyllifolia, Brassica rapa, and Chaenorrhinum minus. Gradients of light and nutrient availability were used to obtain a range of plant sizes for each of these species. Relative allocation to reproductive, inactive, and growth meristems were used to measure reproductive effort, apical dominance, and branching intensity, respectively. We measured allocation to each of these three meristem fates at weekly intervals throughout development and at final developmental stage. At all developmental stages reproductive effort and branching intensity tended to increase with increasing plant size (i.e., due to increasing resource availability) and apical dominance tended to decrease with increasing plant size. We interpret these responses as a strategy for plants to maximize fitness across a range of environments. In addition, significant differences in meristem response among species may be important in defining the range of habitats in which a species can exist and may help explain patterns of species competition and coexistence in habitats with variable resource availability.     

羌塘雪兔子繁殖特征及资源分配的海拔差异

植物种群的生殖特性和资源配置策略是植物生活史研究的重要内容之一,对于理解和预测植被结构和全球变化过程中的适应策略至关重要。该文以青藏高原特有风毛菊属植物羌塘雪兔子(Saussurea wellbyi)为试验材料,分析6个海拔梯度18个居群的花期繁殖特征的变化,并用异速生长模型分析资源投入及资源分配的个体大小依赖关系。结果显示:(1)个体大小、繁殖器官生物量、营养器官生物量、管状小花数目、雄蕊重量、花药长度及花粉数与海拔高度呈负相关(P<0.05),管状小花重量、雌蕊重量、花丝长度及花柱长度与海拔高度呈正相关(P<0.01);(2)营养分配与海拔高度呈负相关(P<0.01),繁殖分配与海拔高度呈正相关(P<0.01);(3)管状小花的数量与重量(P<0.05)、雌蕊重量与雄蕊重量(P<0.01)、花丝长度与花药长度(P<0.01)、花丝长度与花粉数(P<0.01)之间均存在权衡关系;(4)资源投入及资源分配在不同海拔间与个体大小都呈显著正相关(P<0.05),且截距在海拔间差异极显著(P<0.01)。综合分析认为:羌塘雪兔子在不同海拔下的繁殖特征以及大小依赖的资源投入和资源分配模式是羌塘雪兔子与其所处的高山环境长期适应和进化的结果。     

Plant chemical defense: monoterpenes and the growth-differentiation balance hypothesis

Recent studies of allocation to defensive chemicals in plants have provided insights into the ecological controls over plant defensive chemicals. Both developmental and ecological studies now suggest that we can understand the factors influencing allocation to defense by examining the relative availability of resources, external needs for chemical defense, and the internal demands for growth that plants face. These studies have also shed light on one of the more popular theories in plant evolutionary ecology, the growth-differentiation balance hypothesis of plant resource allocation.     

Interpreting reproductive allometry: Individual strategies of allocation explain size-dependent reproduction in plant populations

Size-dependent or allometric relationships between reproductive and vegetative size are extremely common in plant populations. Reproductive allometry where plant size differences are due to environmental variability has been interpreted both as an adaptive strategy of plant growth and allocation, and as the product of fixed developmental constraints. Patterns of development are crucial in defining reproductive allometry but development is not fixed across individuals. For example, environmental adversity (e.g. resource impoverishment) tends to favor reproduction at relatively small sizes – an adaptive response to environmental adversity. While small individuals may have lower reproductive output than large individuals, all plants should maximize their reproductive output and relative allocation to reproduction may be constant across sizes. Thus, where individual plants within a population initiate reproduction at different sizes, no significant reproductive allometry is an appropriate null expectation. Reproductive allometry occurs in plant populations where initiating reproduction at small sizes yields relatively high or low reproductive size at final development. Both of these outcomes are common in plant populations. Our interpretation of reproductive allometry combines previous adaptive and developmental constraint interpretations, and is the first to successfully explain the range of relationships in plant populations where relative allocation has been observed to increase, decrease or remain constant will increasing plant size.     

放牧对内蒙古锡林河流域草地群落植物茎叶生物量资源分配的影响

以内蒙古锡林河流域沿水分梯度分布的灰脉苔草(Carex appendiculata)、贝加尔针茅(Stipa baicalensis)、羊草(Leymus chinensis)、大针茅(Stipa grandis)、小叶锦鸡儿(Caragana microphylla)和冷蒿(Artemisia frigida) 6个草地群落为对象, 研究了围封禁牧与放牧样地中144个共有植物种的高度、丛幅面积、茎、叶和株(丛)生物量、茎叶比等性状。结果表明: 1)在个体水平上, 放牧样地中植物的生殖枝高度、营养枝高度、丛幅面积、单株(丛)生物量、茎、叶生物量和茎叶比均显著低于围封禁牧样地, 植物在放牧干扰下表现出明显的小型化现象; 2)在群落水平上, 放牧亦显著降低了群落总生物量和茎、叶生物量; 3)过度放牧显著改变了物种的资源分配策略, 使生物量向叶的分配比例增加, 向茎的分配比例减少。资源优先向同化器官分配可能是植物对长期放牧干扰的一种重要适应对策; 4)轻度放牧对物种的资源分配没有显著影响, 单株(丛)生物量和群落茎、叶及总生物量均表现出增加趋势, 这与过度放牧的影响正好相反。过度放牧引起的植物个体小型化改变了生态系统中物种的资源分配策略, 进而对生态系统功能产生重要的影响。     

植物交酸系统的进化、资源分配对策与遗传多样性

影响植物自交率进化的选择力量主要体现在两个方面：当外来花粉量不足时,自交可以提高植物的结实率,即雌性适合度（繁殖保障）;而如果进行自交的花粉比异交花粉更易获得使胚珠受精的机会,那么自交也可以提高植物的雄性适合度（自动选择优势）。但是,鉴别什么时候是繁殖保障、什么时候是自动选择优势导致了自交的进化却是极其困难的。花粉贴现降低了自交植物通过异交花粉途径获得的适合度,即减弱了自动选择优势,而近交衰退既减少了自动选择优势也减少了繁残给自交者带来的利益。具有不同交配系统的植物种群将具有不同的资源分配对策。理论研究已经说明,自交率增加将减少植物对雄性功能的资源分配比例,但将使繁殖分配加大,而且在一定条件下交配系统在改变甚至可以导致植物生活史发生剧烈变化,即从多年生变为一年生。文献中支持自交减少植物雄性投入的证据有很多,但是对繁殖分配与自交率的关系目前还没有系统的研究,资源分配理论可以解释植物繁育系统的多样性,尤其是能够3说明为什么大多数植物都是雌雄同体的,自交对植物种群遗传结构的影响是减少种群内的遗传变异,增加种群间的遗传分化,长期以来人们一直猜测,自交者可能会丢掉一些长期进化的潜能,目前这个假说得到了一些支持。     

Effects of phenological constraints on sex allocation in cosexual monocarpic plants

The effects of two phenological constraints in resource investment to reproduction – resource limitation at the flowering stage and unpredictability of resources gained after flowering – on the resource allocation between male and female functions in monocarpic plants are considered using the ESS (evolutionarily stable strategy) approach. The model predicts that the sex allocation including the seed maturation stage has a female bias, when the quantity of reproductive resources available at flowering is small compared with that which is obtained after flowering, or when the cost of seed maturation relative to ovule production is low. The fluctuation of the quantity of resources available for seed maturation favors overproduction of ovules. As a result, more resources are allocated to female function and less to male function at flowering. The ESS allocation depends on the variability of resources and the cost of seed maturation relative to ovule production. The probability that total resource allocation has a female bias becomes higher than 0.5, and it depends on the cost of seed maturation relative to ovule production rather than resource variability. On the other hand, the probability that resource allocation has a female bias decreases with resource variability if we assume that the floral sex ratio is fixed. Future studies of plant sex allocation would profit by taking account of the phenological process of reproduction such as ovule production or seed maturation.     

Physiological dynamics,reproduction‐maintenance allocations,and life history evolution

Allocation of resources to competing processes of growth, maintenance, or reproduction is arguably a key process driving the physiology of life history trade‐offs and has been shown to affect immune defenses, the evolution of aging, and the evolutionary ecology of offspring quality. Here, we develop a framework to investigate the evolutionary consequences of physiological dynamics by developing theory linking reproductive cell dynamics and components of fitness associated with costly resource allocation decisions to broader life history consequences. We scale these reproductive cell allocation decisions to population‐level survival and fecundity using a life history approach and explore the effects of investment in reproduction or tissue‐specific repair (somatic or reproductive) on the force of selection, reproductive effort, and resource allocation decisions. At the cellular level, we show that investment in protecting reproductive cells increases fitness when reproductive cell maturation rate is high or reproductive cell death is high. At the population level, life history fitness measures show that cellular protection increases reproductive value by differential investment in somatic or reproductive cells and the optimal allocation of resources to reproduction is moulded by this level of investment. Our model provides a framework to understand the evolutionary consequences of physiological processes underlying trade‐offs and highlights the insights to be gained from considering fitness at multiple levels, from cell dynamics through to population growth.     

青藏高原特有植物露蕊乌头（毛茛科）从冰期避难所扩张后繁殖资源分配的变化

物种分布范围的形成是进化生态学研究的基本问题之一。但植物的资源分配策略是否与物种边界形成有关一直没有相关研究。青藏高原特有植物露蕊乌头在末次最大冰期时有4个避难所,但冰期后只有一个避难所的种群发生了扩张并最终形成了现代分布格局。以露蕊乌头的避难所种群（同仁种群）和扩张后邻近分布区边缘的两个种群（兴海种群和海北种群）为研究对象,通过比较避难所种群和边缘种群的资源分配方式,探讨露蕊乌头的资源分配与该植物分布区及边界形成的关系。结果发现：1）兴海和海北种群的营养结构（包括根、植株高度和茎叶生物量）均显著低于同仁种群．海北种群的繁殖结构（花数量和花生物量）显著低于同仁和兴海种群,但海北和兴海的繁殖分配均显著高于同仁种群;2）3个种群的繁殖资源与个体大小呈现显著的正相关关系,投入到繁殖资源的比例（繁殖分配）与个体大小呈显著的负相关关系。对露蕊乌头的研究结果一方面进一步证明了个体大小依赖的繁殖分配,但不符合“植物开始繁殖必须达到一定的大小（阈值）”这一结论,这可能与露蕊乌头的生活史特征有关：而另一方面,露蕊乌头在扩张过程中逐渐增加了对繁殖资源投资的比例,说明胁迫生境中有性繁殖对该植物具有更为重要的意义,且露蕊乌头在扩张过程中可能逐渐实现繁殖产出最大化,并可能在边缘种群实现最优繁殖分配进而最终形成该物种分布区的边界,但这一结论仍需在更多的植物类群中验证。     

Evolution of floral dimorphism in a cleistogamous annual, <Emphasis Type="Italic">Impatiens noli-tangere</Emphasis> L. occurring under different environmental conditions

The resource allocation models for the evolution of a mixed production of cleistogamous and chasmogamous flowers were tested in four natural populations of Impatiens noli-tangere L. When we incorporated the estimated parameter values into our basic model, under the assumption that the environmental conditions did not change through the reproductive season, the model predicted the obligate chasmogamy in all four populations. However, including the fluctuation of the fertility of chasmogamous flowers in the model, the seasonal switching of chasmogamous and cleistogamous flower production becomes an evolutionary stable strategy, which explains the reproductive behavior of the individuals in two populations. Only after the relationship between the geitonogamy of chasmogamous flowers and the number of chasmogamous flower production was considered in the model did the simultaneous production of both of the dimorphic flowers become an evolutionary stable strategy. Further, the complete model clarifies the reproductive behavior of the individuals in the other two populations.     

Changes in Reproductive Allocation after Expansion from the Glacial Refugium and Implications for the Distribution Range in the Qinghai Tibet Plateau Native Herb,Gymnaconitum gymnandrum (Ranunculaceae)

A fundamental goal of ecology and evolution is to explain patterns of species distribution and abundance. However, the way in which stable distribution ranges are shaped by natural selection is still poorly understood, especially whether patterns of resource allocation have contributed to the range size and the formation of range boundary received little attention. For annual herb, the maximum reproductive allocation is predicted to be 50%, and thus we predicted that reproductive allocation might contribute to the formation of range boundary since plant will enhance allocations to reproduction in stressful environments. In this study, we presented our data on resource allocation between population from the glacial refegium and those from the marginal populations in Gymnaconitum gymnandrum, an alpine biennial native to the Qinghai Tibet Plateau, aiming to find the contribution of resource allocation to the formation of range boundary. Our results showed that resource allocations to vegetative organs, including roots, plant height and stem leaf biomass, were significantly higher in the refugium population that in the two marginal populations, and allocations to reproductive organs, including flower number and flower biomass, were significantly lower in one marginal population (Haibei population) than in the other marginal population (Xinghai population) and the refugium population (Tongren population). However, reproductive allocation was significantly higher in the marginal populations than in the refugium population. In addition, in each of the three populations, we found a positive relationship between the plant size and flower biomass but a negative relationship between the plant size and reproductive allocation. Our results indicated a size dependent reproductive allocation in Ggymnandrum, but we did not find a size threshold for reproduction in each of the three populations of this plant, which might be attributed to the life history of this biennial herb. We also suggested that reproductive allocation was increased during the process of range expansion and may rise to the optimal reproductive allocation in the marginal populations, which suggested the important role of sexual reproduction for plants in more stressful environments and the formation of range boundary. However, these conclusions need to be further proved in other plant species.     

青藏高原特有植物露蕊乌头 (毛茛科) 从冰期避难所扩张后繁殖资源分配的变化

物种分布范围的形成是进化生态学研究的基本问题之一,但植物的资源分配策略是否与物种边界形成有关一直没有相关研究。青藏高原特有植物露蕊乌头在末次最大冰期时有4个避难所,但冰期后只有一个避难所的种群发生了扩张并最终形成了现代分布格局。以露蕊乌头的避难所种群（同仁种群）和扩张后邻近分布区边缘的两个种群（兴海种群和海北种群）为研究对象,通过比较避难所种群和边缘种群的资源分配方式,探讨露蕊乌头的资源分配与该植物分布区及边界形成的关系。结果发现：1）兴海和海北种群的营养结构（包括根、植株高度和茎叶生物量）均显著低于同仁种群,海北种群的繁殖结构（花数量和花生物量）显著低于同仁和兴海种群,但海北和兴海的繁殖分配均显著高于同仁种群;2）3个种群的繁殖资源与个体大小呈现显著的正相关关系,投入到繁殖资源的比例（繁殖分配）与个体大小呈显著的负相关关系。对露蕊乌头的研究结果一方面进一步证明了个体大小依赖的繁殖分配,但不符合“植物开始繁殖必须达到一定的大小（阈值）”这一结论,这可能与露蕊乌头的生活史特征有关;而另一方面,露蕊乌头在扩张过程中逐渐增加了对繁殖资源投资的比例,说明胁迫生境中有性繁殖对该植物具有更为重要的意义,且露蕊乌头在扩张过程中可能逐渐实现繁殖产出最大化,并可能在边缘种群实现最优繁殖分配进而最终形成该物种分布区的边界,但这一结论仍需在更多的植物类群中验证。     

Rapid antagonistic coevolution between primary and secondary sexual characters in horned beetles

Different structures may compete during development for a shared and limited pool of resources to sustain growth and differentiation. The resulting resource allocation trade-offs have the potential to alter both ontogenetic outcomes and evolutionary trajectories. However, little is known about the evolutionary causes and consequences of resource allocation trade-offs in natural populations. Here, we explore the significance of resource allocation trade-offs between primary and secondary sexual traits in shaping early morphological divergences between four recently separated populations of the horned beetle Onthophagus taurus as well as macroevolutionary divergence patterns across 10 Onthophagus species. We show that resource allocation trade-offs leave a strong signature in morphological divergence patterns both within and between species. Furthermore, our results suggest that genital divergence may, under certain circumstances, occur as a byproduct of evolutionary changes in secondary sexual traits. Given the importance of copulatory organ morphology for reproductive isolation our findings begin to raise the possibility that secondary sexual trait evolution may promote speciation as a byproduct. We discuss the implications of our results on the causes and consequences of resource allocation trade-offs in insects.     

EFFECTS OF LIGHT AND DENSITY ON RESOURCE ALLOCATION IN A FOREST HERB,ASTER ACUMINATUS (COMPOSITAE)

Recent studies show that forest herbs have low sexual reproductive efforts (SRE) and high vegetative reproductive efforts (VRE) and that a variety of factors may affect the levels of reproduction and the distribution patterns of forest species. Aster acuminatus is a micro-successional forest herb common in northern New England. Resource allocation patterns were determined for seven aster patches varying in density and light level. Plant density affects neither plant size nor any aspect of resource allocation, and VRE remains constant over all density and light levels. Light level is, however, significantly correlated with patch location, average plant size and average patch SRE. Only large plants produce flowers suggesting that light affects sexual reproduction indirectly through effects on plant size. The high rhizome and low seed survivorship of this species may partly explain the constant VRE and varying SRE levels, although the resource allocation patterns observed do not correspond well with the predictions of certain theoretical models.     

雌雄异株植物鼠李的生殖分配

以雌雄异株树种鼠李为模式物种,分别从树枝、植株和种群水平上分析了雌雄异株树种鼠李的生殖分配过程,检验了营养生长与生殖过程之间的平衡。结果表明:树枝水平,鼠李年生殖生物量(花生物量+果生物量)投资具有显著的性别差异和个体差异(P<0.001)。雌花生物量大于雄花生物量,雌花生物量最大值为雄花生物量最大值的1.75倍。雌树和雄树的叶片生物量差异不显著(P>0.05)。植株水平上,鼠李生殖生物量(花生物量+果生物量)投资具有显著的性别差异和个体差异(P<0.001),雌树与雄树的花生物量和茎干径向增量差异显著(P<0.05),叶片生物量差异不显著(P>0.05)。鼠李胸径大小对花生物量、叶生物量和茎干径向增量影响显著(P<0.05)。鼠李雌树的花生物量和茎干径向增量均大于雄树。种群水平上,鼠李雄树始花期略早于雌树,2010年雌树和雄树分别于5月28日和5月25日始花。在360 m × 660 m研究样地内种群性比为0.17,卡方检验表明种群性比显著偏离1∶1(P<0.001)。雌树和雄树年平均生长量分别为0.78 mm和0.83 mm。因此,在树枝水平、植株水平以及种群水平上,雌雄异株树种鼠李的营养生长和生殖生长不存在平衡关系。推断鼠李雌树能够通过光合过程获得更多生物量来满足其生殖和营养生长过程需要。