【作者】 王娟；

【导师】 赵秀海；

【作者基本信息】 北京林业大学 ， 生态学， 2014， 博士

【摘要】 植物从外界环境中获取的可利用性资源总量是十分有限的,增加生殖功能资源量必然会降低营养功能资源量的投入,即植物不同功能之间存在着“此消彼长”的权衡关系。生殖、营养生长和生存防御之间的权衡关系是生物生活史的重要组成部分。雌雄异株树种不同性别植株的生殖投资存在差异,所以雌雄异株树种成为检测权衡关系的理想模式植物。雌雄异株树种的雌树繁殖活动能否成功,不仅受到环境资源的限制,也受到雄树对花粉供给的限制。本文分析了生物量异速生长的雌雄二态性特征,研究了雌雄异株植物的生殖与营养生长之间权衡关系,揭示了影响雌雄异株植物繁殖成功的限制性因子,探讨了雌雄异株植物生殖耗费补偿机制。研究结果旨在进一步深化对东北针阔混交林植物繁殖对策的认识。具体研究结果简述如下：1.生物量异速生长特征雌雄二态性鼠李不同类型营养器官的生物量之间高度显著相关；东北鼠李不同类型营养器官生物量之间的相关性不显著。鼠李和东北鼠李不同营养器官生物量的异速生长特征可以利用幂函数和线性模型加以描述,并且生殖器官(花、果实)生物量可通过以胸径和植株长度为自变量的线性模型加以估计。然而,雌雄植株生殖生物量的线性异速生长模型斜率不同,表明雌雄植株开始繁殖时植株大小不同。雌树和雄树的生殖器官生物量具有一致的大小依赖格局。根据生殖分配理论,雌树比雄树要分配更多生物量用于生殖,不可避免会对营养生长产生负向影响。然而鼠李和东北鼠李繁殖雌树并未出现比雄树更低的营养生长现象。2.雌雄异株植物生殖资源权衡由于不同构件水平上植物器官的自组织化程度不同,从不同构件水平上检验鼠李的生殖资源权衡十分必要。在枝条水平、树枝水平和植株水平上,鼠李都不存在当年生殖与叶片营养生长的权衡关系。在树枝水平上检测到了年际间的生殖与营养生长权衡关系,而在其它构件水平上这种年际间的权衡关系并不显著。在种群水平上,2010年鼠李种群性比显著偏雌,2011年种群性比则不显著偏离1：1。在枝条水平、树枝水平和植株水平,东北鼠李雌雄植株的当年生殖与叶片营养生长均不存在权衡关系,但雌树存在着年际间的权衡关系。在种群水平上,2010和2011年东北鼠李种群性比显著偏雌。因此,植物器官的自组织化程度和植株性别影响着植物生殖资源的权衡关系。2011年和2012年,簇毛槭在枝条水平上存在当年生殖与营养生长的权衡关系。这种权衡关系具有显著的性别依赖性,雌雄植株的生殖与营养生长之间均呈负相关关系,但雄树表现更为显著。簇毛槭构件水平的自组织化程度影响了生殖权衡关系,雌树年际间的权衡关系仅表现在树枝水平和植株水平上。2012年雌树的繁殖量与前两年的繁殖量呈负相关关系。簇毛槭种群性比显著偏雄,并且2011和2012年,雌树在较大径级上具有更高的死亡率。3.雌雄异株植物生殖成功影响因子鼠李雌树死亡率高于雄树,雌树生殖与存活之间存在着此消彼长的权衡关系。2010-2012年观测数据显示,海拔、邻体竞争和雌树大小对坐果率都没有显著影响。雌树与“距最近雄树距离”显著负向影响雌树坐果率。雌树果实数量和坐果率随着“距最近雄树距离”的增加而下降,并且这种负向关系可以利用指数模型加以描述。研究结果支持了花粉限制是影响鼠李繁殖成功与否关键因子的论点。坡度显著正向影响东北鼠李生殖过程和生殖资源分配权衡关系,随着坡度增加,雌树坐果率、果数和生殖与营养生长权衡显著增大。土壤养分普遍负向影响生殖及资源分配过程。速效氮、全钾、速效钾、有效镁负向影响着坐果率；速效氮、全磷、速效钾、有效镁负向影响着果数；速效氮、全磷、速效磷、速效钾、有效镁负向影响着花数；全磷、全钾、速效钾、有效镁负向影响着生殖与营养生长权衡。因此,土壤养分增加将降低生殖资源分配,而增加营养生长资源分配。土壤全镁含量高度正向影响坐果率、花数、果数以及生殖与营养生长权衡关系。此外,东北鼠李生殖分配具有显著的大小依赖性。簇毛槭雌雄植株的生殖生物量与营养生长生物量均显著线性相关(p<0.05),营养生长生物量随着生殖生物量的增加而增大。地形因子、土壤湿度、叶面积指数、雌树胸径大小显著影响着雌树花数,但对果数、坐果率以及生殖与营养生长权衡关系都没有显著影响。坡度显著负向影响花数,土壤湿度、雌树胸径大小则显著正向影响雌树花数。叶面积指数显著正向影响花粉供给量,花粉供给量则显著负向影响雌树花数,因此叶面积指数可通过影响花粉环境而间接作用于雌树花数。地形因子、土壤湿度、叶面积指数、植株大小对雄树花数和生殖与营养生长之间权衡都没有影响。4.雌雄异株植物生殖耗费补偿机制根据植物生活史理论,雌树由于开花、结实要付出更高的生殖代价,从而会导致其营养生长降低。但鼠李生殖与营养生长之间并不存在权衡关系,雌树并未由于生殖活动而降低其营养生长。这暗示某种补偿机制弥补了雌树生殖活动消耗掉的资源。光响应曲线分析显示,在低光强下鼠李雌树与雄树叶片的净光合速率差异并不显著；而在较高光强下雌树叶片的净光合速率大于雄树。因此,鼠李雌树叶片具有更强的光合能力,这种高光合能力弥补了雌树自身较高的生殖耗费量。更多还原

【Abstract】 When a plant increases resource allocation to reproduction from its limited reserves, the allocation to the other functions is reduced. The trade-off between reproduction, vegetative growth and maintenance is a major issue in the life history of an organism. Dioecious plants provide an excellent opportunity for detecting such possible trade-offs in resource allocation. The reproductive success of a female plant in a dioecious species may be affected by pollen limitation and resource limitation. This study presents the dimorphism in reproductive allometry, studies the trade-offs between reproduction and vegetative growth, reveals the limited factors of reproductive success, and detects compensating mechanism for reproduction costs. This paper aims to deepen the understanding for plant reproductive strategy in mixed broadleaf-conifer forest in Northeastern China. The brief results are as follows:1. The dimorphism in vegetative and reproductive allometriesRhamnus davurica shows highly significant correlations for all selected combinations of different vegetative components. These correlations are much less pronounced, and sometimes even non-significant in Rhamnus schneideri. An power function and a linear model were found suitable for describing different components of the vegetative allometry. In addition, a linear regression was used to estimate the number of flowers and/or fruits based on observed stem size. However, the slope of the linear relations differs between the sexes again indicating gender-related differences in reproductive size. Both females and males show consistent patterns of reproductive size dependency. According to theory, females allocate more biomass to reproduction than males, which negatively affects their vegetative growth. However, in this study, flowering females did not show less vegetative growth than males suggesting that the two Rhamnus species behave contrary to expectation.2. The trade-offs between reproduction and vegetative growth The self-organization of plant organ is different at different modular levels. The trade-offs between reproduction and vegetative growth was detected at different modular levels. There were no intra-annual trade-offs between reproduction and foliage biomass in either sex at shoot/sub-branch level, branch level and shrub level. Inter-annual trade-offs were detected in females. Inter-annual trade-offs existed at branch level in R. davurica females. At the population level, the sex ratio was female-biased in2010, and it did not significantly deviate from1:1in2011in R. davurica. There were no intra-annual trade-offs between reproduction and foliage biomass at shoot/sub-branch level, branch level and shrub level. Inter-annual trade-offs existed at all three different modular levels in R. schneideri females. At the population level, the sex ratios were significantly female-biased in both2010and2011in R. schneideri. This study has shown that the degree of autonomy of the different plant organs influenced the trade-offs between reproduction and growth, which suggests a species-and sex-dependent modular autonomy.These trade-offs were examined at three different modular levels of Acer barbinerve shrubs, i.e., shoot, branch and shrub levels. An intra-annual trade-off was detected at the shoot level for both genders in2011and2012. Both males and females showed a negative correlation between reproduction and vegetative growth, but this was more prominent in males. For the females of the species, inter-annual trade-offs were only found at branch and shrub levels. Slightly negative correlations in females were detected between reproduction in2012and reproduction in the two previous years. The gender ratio was significantly male-biased during the three successive years of our investigation. Females had higher mortality rates in the larger DBH classes, both in2011and2012.3. Limitations to reproductive success in the dioecious plantThe mortality rate of females was higher than that of males indicating a trade-off between reproduction and survival. In the three years of the study (2010-2012), elevation, competition and female size had no significant effect on the fruit set. The distance to the nearest male, however, had a significant effect on fruit set. Number of fruits and fruit set were decreased with increasing distance to the nearest male. It was possible to estimate maximum fruit set, based on the comparatively large dataset. The number of fruits and the fruit set are exponentially related to the distance to the nearest male and the relationships are described by an exponential model. The results of this study support the importance of pollen limitation on the reproductive success in R. davurica.The trade-offs between reproduction and vegetative growth was negatively affected by the slope for R. schneideri. The fruitset, the number of fruit and the trade-offs between reproduction and vegetative growth increased with the increase of slope. Reproduction and resource allocation was negatively affected by the soil nutrient. Such as, the fruitset was negatively affected by available nitrogen, total potassium, available potassium and available magnesium. The number of fruit was negatively affected by available nitrogen, total phosphorus, available potassium and available magnesium. The number of flower was negatively affected by available nitrogen, total phosphorus, available phosphorus, available potassium and available magnesium. The trade-offs between reproduction and vegetative growth was negatively affected by total phosphorus, total potassium, available potassium and available magnesium. Thus, the increase of soil nutrient will decrease the resource allocation in reproduction, but increase in vegetative growth. The fruitset, the number of flower, the number of fruit and the trade-offs between reproduction and vegetative growth positively affected by soil total magnesium. In addition, reproductive allocation is significantly size-dependent.Reproductive biomass related significantly with vegetative biomass for both male and female in A. barbinerve, and vegetative biomass increased with the increase of reproductive biomass. Topography, soil moisture, leaf area index and female dbh affected significantly the number of flower, but did not for the number of fruit, the fruitset and the trade-offs between reproduction and vegetative growth. The number of flower was negatively affected by the slope, but positively affected by soil moisture and female dbh. The pollen supply quantity was positively affected by leaf area index, while the number of flower in female trees was negatively affected by the pollen supply quantity. Thus, leaf area index can affect indirectly the number of flower in female trees. But topography, soil moisture, leaf area index and male dbh size did not significantly associate with the number of flower and the trade-offs between reproduction and vegetative growth.4. Compensation mechanism for reproductive costs in dioecious plantsBased on the theory of life history, female tree will pay higher cost in reproduction because of flowering and fruting. So female may have a lower vegetative growth than male. However, that trad-off between vegetation and reproduction does not exist in female tree of R. davarica. Although female trees of R. davarica have higher reproductive biomass, meanwhile females also have higher vegetative biomass. It means that female may have compensatory mechanism for their higher reproductive costs. Acorrding to the result of light response curve, female has higher net photosynthesis rate when the light intensity is higher. It indicates that females have higher photosynthesis ability than males to compensate their higher reproductive cost.更多还原