Response of resource allocation of Saussurea leontodontoides during its fruiting stage to the elevation

植物资源分配是目前植物生态学研究的热点问题, 主要集中在性分配和繁殖分配两个方面。该研究以分布在青藏高原的狮牙草状风毛菊(Saussurea leontodontoides)作为研究材料, 研究了6个海拔高度上果期植株的繁殖特征及资源分配的差异, 并用异速模型分析了繁殖性状及资源分配与个体大小的关系。结果显示: 1)狮牙草状风毛菊的个体大小、繁殖器官生物量、营养器官生物量、种子数和营养分配均与海拔存在极显著负相关关系, 百粒质量和繁殖分配与海拔存在极显著正相关关系。2)在不同海拔高度下, 百粒质量、种子数、繁殖器官生物量及营养分配与植株个体大小呈正相关关系; 繁殖分配与植株个体大小呈负相关关系; 而营养器官生物量与植株个体大小呈极显著正相关关系。这表明海拔和个体大小对狮牙草状风毛菊的繁殖对策有不同程度的影响, 狮牙草状风毛菊通过增加繁殖部分的生物量和百粒质量来适应高海拔的胁迫环境。     

狮牙草状风毛菊果期资源分配对海拔的响应

植物资源分配是目前植物生态学研究的热点问题, 主要集中在性分配和繁殖分配两个方面。该研究以分布在青藏高原的狮牙草状风毛菊(Saussurea leontodontoides)作为研究材料, 研究了6个海拔高度上果期植株的繁殖特征及资源分配的差异, 并用异速模型分析了繁殖性状及资源分配与个体大小的关系。结果显示: 1)狮牙草状风毛菊的个体大小、繁殖器官生物量、营养器官生物量、种子数和营养分配均与海拔存在极显著负相关关系, 百粒质量和繁殖分配与海拔存在极显著正相关关系。2)在不同海拔高度下, 百粒质量、种子数、繁殖器官生物量及营养分配与植株个体大小呈正相关关系; 繁殖分配与植株个体大小呈负相关关系; 而营养器官生物量与植株个体大小呈极显著正相关关系。这表明海拔和个体大小对狮牙草状风毛菊的繁殖对策有不同程度的影响, 狮牙草状风毛菊通过增加繁殖部分的生物量和百粒质量来适应高海拔的胁迫环境。     

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。     

高山垫状植物团状福禄草开花面积与方位随海拔的变化及其适应性

作为高山生态系统中的奠基种(foundation species), 垫状植物自身种群的繁殖与扩张, 对高山生态系统功能稳定性起着关键作用。但是, 垫状植物如何在极端环境条件下实现资源的有效利用与分配, 达到繁殖最优化, 至今鲜为人知。该研究在滇西北白马雪山沿海拔梯度选择具有不同坡度及坡向的5个团状福禄草(Arenaria polytrichoides)种群, 调查、比较种群内、种群间以及具有不同性系统的植株个体之间的开花面积比、开花方位, 并分析不同生态因子对其开花特性的影响。结果表明: 随着海拔的升高, 团状福禄草个体变小, 其分配到开花的资源比例总体上随海拔上升呈现下降的趋势, 说明团状福禄草的繁殖分配受到由海拔所引起的生态因子的调控。但是, 部分低海拔种群内植物个体的繁殖分配显著低于部分高海拔种群, 说明海拔并非控制植物繁殖分配的唯一因素。此外, 植株开花总面积随植株个体增大而增加, 但开花面积比却随个体增大而变小, 说明植株分配到开花的资源增长速率可能低于植株个体的增长速率。在性别差异方面, 两性植株对开花的资源分配比例要显著高于雌性植株, 但是, 其差异程度受到海拔因素的影响。最后, 在同一种群内, 团状福禄草在冠层表面不同方位上的开花面积比存在显著差异性, 这种差异性在不同种群之间又具有不同的表现形式。     

Altitudinal variation in flowering area and position and their ecological significances of an alpine cushion Arenaria polytrichoides,a gynodioecious herb

Aims As foundation species in the alpine ecosystems, the reproduction and recruitment of alpine cushion plants are very important for sustaining the alpine ecosystem functions. However, it still remains unclear that how cushion plants effectively allocate resources to optimize reproductive fitness.Methods Here we selected five populations of a gynodioecious herb Arenaria polytrichoides with different exposures and slopes along an altitudinal gradient on the Baima snow mountain in northwest Yunnan, southwest China, to investigate and compare flowering area and positions, within and among populations and between female and hermaphroditic morphs. By doing so, we further discuss how the environmental stresses affect the cushion’s flowering attributes thus the population-level reproduction.Important findings The results showed that, individual plant size and resources allocated to flowering (flowering area %) both decreased with increasing elevation, indicating that the reproductive allocation strategy was significantly affected by elevation. However, a population at lower elevation showed lower reproductive investment than higher populations, suggesting that elevation was not the only factor affecting the cushion’s reproductive allocation. In addition, absolute flowering area increased with increasing individual size, but the flowering area ratio decreased, indicating that the increases in reproductive allocation are fewer than that in vegetative allocation. Hermaphroditic individuals invested more resources to flowering than females did, but again, such effect was affected by elevation. Moreover, within a single population, the flowering areas were significantly different among the four directions (east, south, west and north) within one single individual canopy, but such differences varied in different populations.     

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。     

青藏高原东缘野生暗紫贝母生物量分配格局对高山生态环境的适应

从时空尺度研究了青藏高原东缘野生暗紫贝母(Fritillaria unibracteata)生物量分配特征对高山环境条件的生态适应。通过海拔梯度、群落类型、群落盖度、群落透光率4个变量的分析, 间接探讨了高山环境条件下水分、热量、光照和土壤养分等主要环境因子对暗紫贝母生物量分配的影响, 并主要研究了海拔梯度这一综合要素的生态效应。同时, 从时间尺度上研究了暗紫贝母不同生活史阶段的生物量分配模式, 以期了解不同发育阶段高山植物对于环境要素的适应特征。研究结果表明: 1)在一定的空间范围内, 4个环境变量中仅海拔梯度对暗紫贝母单株鳞茎生物量及总生物量的影响差异显著, 且生物量积累随海拔升高而减小。2)在空间尺度上, 海拔梯度为野生暗紫贝母生长的主要限制因子, 表明在高山地区热量条件对植物生长具有明显的制约作用, 同时不同生活史阶段的暗紫贝母其生物量分配模式对海拔梯度的响应也存在着一定的差异。2年生贝母的鳞茎生物量分配随海拔升高而降低, 叶生物量分配随之增加。3年生和4年生贝母鳞茎及叶生物量分配在不同海拔梯度上比较稳定, 而茎生物量分配随海拔升高而降低, 有性生殖(花)分配则随之而增加。各生活史阶段植株根生物量在不同海拔梯度上分配稳定。3)在时间尺度上, 不同生活史阶段贝母生物量分配模式存在显著差异。根和茎生物量分配随生活史阶段的增加而显著增加, 而鳞茎和叶生物量分配则随之显著减少。单株鳞茎生物量在3年生阶段达到最大。     

Effects of denudation and burial on growth and reproduction of <Emphasis Type="Italic">Artemisia ordosica</Emphasis> in Mu Us sandland

Plants in a dune environment have a high risk of being denudated by wind or buried by sand. We conducted a field experiment to assess growth and reproductive performance as well as biomass allocation of Artemisia ordosica after denudation and burial. Height growth decreased after denudation, but remained constant after burial; biomass was reduced by severe burial, but not by moderate ones. Vegetative growth measured by current-year generated vegetative branches declined with increasing severity of burial. Reproductive maturity was not affected by either denudation or burial, and reproduction decreased only after severe denudation. After denudation, biomass allocated to reproduction was greatly reduced, as shown by strongly reduced biomass allocation to fruits and whole reproductive branches, but that allocated to current-year vegetative growth was maintained. Biomass allocation to reproduction and vegetative growth remained rather stable after burial. Current-year reproductive-to-vegetative-biomass ratio was lower after denudation than after burial, indicating that vegetative growth was more favored by A. ordosica after denudation. These modifications are adaptive in the fluctuating environment of mobile sand dunes where denudation and burial frequently occur.     

紫翅猪毛菜、钠猪毛菜不同个体大小繁殖分配差异及随海拔的变化

以新疆准噶尔盆地藜科猪毛菜属植物紫翅猪毛菜(Salsola affinis C.A.Mey)、钠猪毛菜(Salsola nitraria Pall)为研究对象,用繁殖分配比例的方法对比分析了两种猪毛菜不同海拔同一种群内不同个体大小繁殖分配的特点,并用异速生长模型分析了不同海拔繁殖生物量与营养生物量之间分配与个体大小的依赖关系。结果发现:1)不同海拔繁殖生物量(R)与营养生物量(V)呈不同程度的异速生长。紫翅猪毛菜随海拔的升高R-V的异速生长斜率显著升高,截距随海拔的升高没有显著增加;而钠猪毛菜的斜率随海拔升高显著降低,截距则显著升高。2)紫翅猪毛菜在较低海拔个体大小与繁殖分配呈负相关,在较高海拔呈正相关;钠猪毛菜在较低海拔个体大小与繁殖分配呈正相关,在较高海拔呈负相关;两种猪毛菜繁殖分配的适应对策相反。3)将同一种群个体大小分成大、中、小3种类型,多重比较发现紫翅猪毛菜在较低海拔,中小个体的繁殖分配显著高于大个体的繁殖分配;在较高海拔,大个体的繁殖分配显著高于中小个体的繁殖分配。钠猪毛菜在较低海拔,大个体的繁殖分配显著高于中、小个体的繁殖分配;在较高海拔,小个体的繁殖分配显著高于大、中个体的繁殖分配。综合分析认为:两个物种随海拔变化产生不同的繁殖分配策略,除遗传效应外,环境和个体大小对钠猪毛菜繁殖分配的变化均产生重要影响,而紫翅猪毛菜繁殖分配的变化主要由海拔差异导致。由于微生境对同一种群的个体大小产生影响,进而产生不同的繁殖分配模式,所以在干旱区更应重视个体大小对繁殖分配的影响。     

Density-dependent reproductive and vegetative allocation in the aquatic plant Pistia stratiotes (Araceae)

Pistia stratiotes is an aquatic macrophyte that grows in temporary-ponds in the southern Pantanal, Brazil. It reproduces both sexually and asexually and is usually observed forming dense mats on the water surface, a condition favored by the plant's vegetative reproduction coupled with an ability for rapid growth. In this study we examined the effect of densely crowded conditions on the production of reproductive and vegetative structures. In addition, we verified whether there is a trade-off between clonal growth and investment in sexual reproductive structures, and whether there is an allocation pattern with plant size. Individual plant biomass and the number of the rosettes producing sexual reproductive structures and vegetative growth structures both increased with density. Increase in plant size resulted in increased proportional allocation to sexual reproductive structures and vegetative growth structures. Allocation of biomass to reproduction did not occur at the expense of clonal growth. Thus, the density response appears as a increase of rosettes producing sexual reproductive structures and vegetative growth structures. Therefore, long leaves and stolons may be adaptive under densely crowded conditions where competition for light is intense. An important aspect in the study of trade-offs is the size-dependency of the allocation patterns .Usually, larger plants produce more biomass. Therefore, larger plants can allocate more biomass to both vegetative and sexual reproduction than smaller plants and thus show a positive correlation between both traits rather than the expected negative one.     

青藏高原东缘星状风毛菊生殖分配对海拔的响应

通过采样调查法和烘干称量法, 检测了青藏高原东缘不同海拔20个居群星状风毛菊(Saussurea stella)的花部特征, 研究其花部特征对海拔及个体大小的响应。结果表明: 1)繁殖分配是依赖个体大小的, 个体越大, 繁殖分配越小; 2)花期繁殖器官和营养器官的生物量、头状花序的数量及大小、雌雄功能以及雄性内部花丝与花粉之间均存在资源分配上的权衡; 3)星状风毛菊通过花部特征的变异响应海拔的变化。研究发现, 星状风毛菊通过花部特征的变异, 特别是花柱和花丝的伸长及投入更多资源于吸引结构花瓣, 以此来补偿该种在高海拔地区因传粉者减少、活动频率降低和花粉数减少等因素对传粉带来的影响, 使其能够在高海拔的胁迫环境下有效地传粉, 完成有性繁殖。     

Plant population differentiation and climate change: responses of grassland species along an elevational gradient

Mountain ecosystems are particularly susceptible to climate change. Characterizing intraspecific variation of alpine plants along elevational gradients is crucial for estimating their vulnerability to predicted changes. Environmental conditions vary with elevation, which might influence plastic responses and affect selection pressures that lead to local adaptation. Thus, local adaptation and phenotypic plasticity among low and high elevation plant populations in response to climate, soil and other factors associated with elevational gradients might underlie different responses of these populations to climate warming. Using a transplant experiment along an elevational gradient, we investigated reproductive phenology, growth and reproduction of the nutrient‐poor grassland species Ranunculus bulbosus, Trifolium montanum and Briza media. Seeds were collected from low and high elevation source populations across the Swiss Alps and grown in nine common gardens at three different elevations with two different soil depths. Despite genetic differentiation in some traits, the results revealed no indication of local adaptation to the elevation of population origin. Reproductive phenology was advanced at lower elevation in low and high elevation populations of all three species. Growth and reproduction of T. montanum and B. media were hardly affected by garden elevation and soil depth. In R. bulbosus, however, growth decreased and reproductive investment increased at higher elevation. Furthermore, soil depth influenced growth and reproduction of low elevation R. bulbosus populations. We found no evidence for local adaptation to elevation of origin and hardly any differences in the responses of low and high elevation populations. However, the consistent advanced reproductive phenology observed in all three species shows that they have the potential to plastically respond to environmental variation. We conclude that populations might not be forced to migrate to higher elevations as a consequence of climate warming, as plasticity will buffer the detrimental effects of climate change in the three investigated nutrient‐poor grassland species.     

Biomass Allocation in the Dioecious Tropical Palm Chamaedorea tepejilote and Its Life History Consequences

Abstract The patterns of resource allocation are described for a dioecious tropical palm, Chamaedorea tepejilote. Resource allocation was measured by harvesting fifteen plants of C. tepejilote. The relative allocation of biomass in the stem increased with the size of the plant; that in the leaves decreased and that in the other structures remained roughly constant. Female plants showed a greater total reproductive effort, though male plants produced more inflorescences during the flowering season. Both male and female plants allocated more resources to prop root than to hypogeal roots. The annual productivity of reproductive and vegetative parts of C. tepejilote was estimated using allometric relationships for different plant structures and from demographic data obtained from the field. Annually, female plants allocated significantly more resources to leaves than male plants. Yearly productivity of inflorescences was higher for male plants, while female plants had greater total reproductive productivity (inflorescences and fruits). Correlation analysis showed an increase in reproductive effort with plant size, and an inverse relationship between fecundity and probability of survival, fecundity and residual reproductive value, and reproductive effort and life expectancy; these relationships suggested a cost in reproduction. Additionally, mature plants with different growth rates exhibited differences in fecundity: tall plants (>2.5m height) that grew more than 40 cm in height in four years had lower values of fecundity in comparison to plants of slower growth. These data were discussed in the context of the implications in the life history of a dioecious tropical plant.     

谷子的亲缘识别能力及其与种植密度和土壤养分水平的关系

为探明作物是否具有识别邻株身份的能力以及这种能力是否受到环境因子的调控,通过大田试验,研究邻株身份(亲缘株、非亲缘株和陌生株)、种植密度和土壤养分水平的交互效应对谷子(Setaria italica)地上部分生物量分配的影响。结果表明,谷子与亲缘株为邻时的净繁殖生物量分配和种子生物量分配,比与非亲缘株为邻时显著提高,且营养生物量分配显著降低(P<0.05)。在高种植密度条件下,亲缘组谷子的穗长、净繁殖生物量分配和种子生物量分配显著大于非亲缘组,而营养生物量分配显著小于非亲缘组(P<0.05)。随着土壤养分水平提高,亲缘组谷子的种子生物量分配显著增加,营养生物量分配显著减少(P<0.05)。由此推断,谷子具有对亲缘邻株的识别能力,且这种能力受种植密度和土壤养分水平的调控,在高种植密度和高土壤养分水平条件下,谷子的亲缘邻株识别能力较强。     

Sensitivity of growth and biomass allocation patterns to increasing nitrogen: a comparison between ephemerals and annuals in the Gurbantunggut Desert,north-western China

Background and Aims

Biomass accumulation and allocation patterns are critical to quantifying ecosystem dynamics. However, these patterns differ among species, and they can change in response to nutrient availability even among genetically related individuals. In order to understand this complexity further, this study examined three ephemeral species (with very short vegetative growth periods) and three annual species (with significantly longer vegetative growth periods) in the Gurbantunggut Desert, north-western China, to determine their responses to different nitrogen (N) supplements under natural conditions.

Methods

Nitrogen was added to the soil at rates of 0, 0·5, 1·0, 3·0, 6·0 and 24·0 g N m⁻² year⁻¹. Plants were sampled at various intervals to measure relative growth rate and shoot and root dry mass.

Key Results

Compared with annuals, ephemerals grew more rapidly, increased shoot and root biomass with increasing N application rates and significantly decreased root/shoot ratios. Nevertheless, changes in the biomass allocation of some species (i.e. Erodium oxyrrhynchum) in response to the N treatment were largely a consequence of changes in overall plant size, which was inconsistent with an optimal partitioning model. An isometric log shoot vs. log root scaling relationship for the final biomass harvest was observed for each species and all annuals, while pooled data of three ephemerals showed an allometric scaling relationship.

Conclusions

These results indicate that ephemerals and annuals differ observably in their biomass allocation patterns in response to soil N supplements, although an isometric log shoot vs. log root scaling relationship was maintained across all species. These findings highlight that different life history strategies behave differently in response to N application even when interspecific scaling relationships remain nearly isometric.     

川西风毛菊果期资源分配对海拔的响应

以分布于青藏高原东缘的川西风毛菊为试验材料,研究了其不同海拔高度16个居群的果期资源分配。结果显示:1)随着海拔的升高,个体大小、繁殖器官生物量、营养器官生物量、根系质量、茎叶质量以及每株植物种子总数量均不断减小,但种子百粒重不断增加;2)繁殖分配和根系分配与海拔呈正相关关系,营养分配和茎叶分配与海拔呈负相关关系;3)果期繁殖分配和营养分配、根系分配和茎叶分配以及种子数量与百粒重之间均存在资源分配上的权衡。研究结论:1)海拔作为外界因子对川西风毛菊果期各生物量及资源分配有显著的影响;2)随着海拔的升高,川西风毛菊通过增加繁殖分配,根系分配以及种子百粒重来适应胁迫环境,提高自身的适合度。     

Above- and Belowground Biomass Allocation in Shrub Biomes across the Northeast Tibetan Plateau

Biomass partitioning has been explored across various biomes. However, the strategies of allocation in plants still remain contentious. This study investigated allocation patterns of above- and belowground biomass at the community level, using biomass survey from the Tibetan Plateau. We explored above- and belowground biomass by conducting three consecutive sampling campaigns across shrub biomes on the northeast Tibetan Plateau during 2011–2013. We then documented the above-ground biomass (AGB), below-ground biomass (BGB) and root: shoot ratio (R/S) and the relationships between R/S and environment factors using data from 201 plots surveyed from 67 sites. We further examined relationships between above-ground and below-ground biomass across various shrub types. Our results indicated that the median values of AGB, BGB, and R/S in Tibetan shrub were 1102.55, 874.91 g m^-2, and 0.85, respectively. R/S showed significant trend with mean annual precipitation (MAP), while decreased with mean annual temperature (MAT). Reduced major axis analysis indicated that the slope of the log-log relationship between above- and belowground biomass revealed a significant difference from 1.0 over space, supporting the optimal hypothesis. Interestingly, the slopes of the allometric relationship between log AGB and log BGB differed significantly between alpine and desert shrub. Our findings supported the optimal theory of above- and belowground biomass partitioning in Tibetan shrub, while the isometric hypothesis for alpine shrub at the community level.     

腾格里沙漠人工固沙植被中油蒿的生长及生物量分配动态

植物的资源分配模式反映了对环境的生态适应对策。2007年整个生长季, 采用生物量法对腾格里沙漠东南缘固沙植被区半灌木油蒿(Artemisia ordosica)地上部分各器官的生长及资源分配格局动态进行了研究。结果表明: 不同时期各器官的生长速率不同, 光合产物在各器官中的分配也不是等量的, 而是按一定的顺序在不同时期有不同的分配中心; 2007年油蒿的营养生长、繁殖输出、生殖枝大小都显著大于年降水量不足其一半的年份, 而繁殖分配和头状花序大小没有差异; 营养器官生物量大的油蒿总的繁殖输出也大, 但生殖期内营养生长和生殖生长既不同时也不等速, 表明资源分配的权衡(Trade-off)是存在的; 固沙植被建立以后, 随着时间延长, 油蒿的当年总生物量、繁殖输出、繁殖器官生物量分配有减小的趋势, 但不显著。     

新疆郁金香营养生长、个体大小和开花次序对繁殖分配的影响

植物有性繁殖与资源分配的关系研究对于揭示植物生活史特征及繁育系统进化具有重要意义。新疆郁金香(Tulipa sinkiangensis)是新疆天山北坡荒漠带特有的一种多年生早春短命植物。在自然生境中,该物种仅以有性繁殖产生后代,每株能产生1-8朵花,且不同植株上的花数及果实数以及花序不同位置上的花与果实大小明显不同。本文通过对新疆郁金香有性繁殖与营养生长及植株大小的关系以及花序中不同位置花及果实间的资源分配研究,旨在揭示营养生长、个体大小及开花次序对其繁殖分配的影响。结果表明:在开花和果实成熟阶段,新疆郁金香植株分配给营养器官(鳞茎和地上营养器官)与繁殖器官的资源间均存在极显著的负相关关系(P<0.01),说明其植株的营养生长与生殖生长间存在权衡关系。多花是新疆郁金香的一个稳定性状,其植株上花数目、花生物量、果实生物量和种子数量与植株生物量间均呈极显著的正相关关系(P<0.01),说明新疆郁金香植株的繁殖分配存在大小依赖性。在具2-5朵花的新疆郁金香植株中,花序内各花的生物量、花粉数和胚珠数、结实率、果实生物量、结籽数、结籽率及种子百粒重按其开花顺序依次递减,说明花序内各花和果实的资源分配符合资源竞争假说。植株通过减少晚发育的花或果实获得的资源来保障早发育的花或果实获得较多的资源,从而达到繁殖成功。