【作者】 Wisdom Japhet；

【导师】 周道玮；

【作者基本信息】 东北师范大学 ， 生态学， 2009， 博士

【摘要】 表型可塑性是植物一个重要特征,使它们能在一定范围内的环境中存活。虽然可塑性被广泛地研究,但这些研究中的大部分是在相对简单的环境中进行,并且大多数研究将可塑性按两个部分之间生物量的相对分配定义。这忽略了能够表明关于植物策略问题的其它特性的潜在影响。植物的构件组织状态表明,整株植物的可塑性同时依赖于特征的数量和个体特性的可塑响应,结果是植物特征对不同资源的可塑响应量不同,因此造成特征之间可塑响应的“层次结构”。只有少数研究考虑了特性之间可塑性大小的问题。本研究检验了以下假设:生长于田间的植物萌发时间和种群密度的差异将导致不仅生物量特征,结构特征也会有显著的可塑性以提高对有限资源的获取。我还应用了表型可塑性的知识以增进对于作物响应于农业管理实践的理解。在不同密度和播期下种植的荞麦(Fagopyrum esculentum),茎生物量分配、叶生物量分配、叶根比,及单株茎长、茎直径、分枝长和分枝数都有显著的可塑性。变异系数的计算指示,密度和播期处理的特征可塑性的量有某些一致性。在曼陀罗(Datura stramonium)的移植种群中,比叶面积、叶面积比和叶片数都具有显著的可塑性,这些特征都与捕光能力对高密度的响应有关。同样地,这种植物在响应于四种环境因子的限制中展示出显著的繁殖分配的可塑性。对不同物种可塑性进行比较,发现荞麦的竞争结构表现出可塑性,另一方面,谷子倾向于在繁殖分配上表现出更大的可塑性。这种不同的响应可能影响两种作物响应于密度的方式。对于荞麦,高密度下的产量损失可以归因于结构竞争的可塑性,而不是繁殖分配;相反,对于高密度种植下的谷子,由于繁殖分配的增加,产量损失得以避免。本文证实,可塑性是实际环境中表型变异的主要来源之一,而不是先前认为的微不足道的“噪音”(新达尔文主义)(neo- Darwinian)。更多还原

【Abstract】 Phenotypic plasticity is an important attribute of plants which enables them to survive across a range of environments. Although plasticity is widely studied, majority of the studies were conducted in relatively simple environments. Also most studies have defined plasticity in terms of the relative allocation of biomass between two compartments. This ignores the potential contribution of other traits that could tell something about a plant’s strategy. The modular organization of plants suggest that, the plasticity of the whole plant depends on the plastic responses of both number and individual characters of traits, with the consequence that plant traits could differ in magnitude of plastic responses to different resources, and thus resulting in a“hierarchy”of plastic responses amongst traits. Only a few studies have considered the magnitude of plasticity amongst traits.In this study, we tested the hypothesis that differences in germination timing and population density for plants growing in the field will lead to significant plasticity not only in biomass traits, but architectural traits that enhances the capture of limited resources. We also used the knowledge of phenotypic plasticity to enhance the understanding of crop response to farm management practices.In Fagopyrum esculentum grown under different density and sowing date, there was significant plasticity in stem mass ratio, leaf mass ratio and leaf to root ratio, as well as single measures of stem length, stem diameter, branch length and number of branches. Computation of coefficient of variation (CV) indicated some consistency in magnitude of trait plasticity for both density and sowing date treatments. In a colonizing population of Datura stramonium, there was significant plasticity in specific leaf area, leaf area ratio and number of leaves; traits that are associated with light capture in response to high density. Similarly, this species exhibited significant plasticity in reproductive allocation in response to the limitation of four environmental factors. When their plasticity patterns were compared, buckwheat displayed plasticity in competitive structures, millet on the other hand, preferred to display more plasticity in reproductive allocation. These different responses could influence the way these two crops would response to high density. For buckwheat, the loss in yield at high density could be attributable to the plastic increase in competitive structures instead of allocation to reproduction. Conversely, for Millet sown at high density, yield loss was prevented due to the increased in reproductive allocation. This thesis demonstrate that plasticity is a major source of phenotypic variation in the real world, contrary to the earlier (neo- Darwinian) view of this as trivial‘noise.更多还原