表型可塑：植物表型变异的一个重要来源

论文摘要

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）。

论文目录

• Abstract
• 摘要
• Chapter I
• 1.1 General Introduction
• 1.2 Developmental plasticity and evolution
• 1.3 Ecological constraints on the evolution of plasticity in plants
• 1.4 Mechanisms of plastic response
• 1.5 Challenges in interpreting plasticity
• Chapter II Evidence of phenotypic plasticity in the response of Fagopyrum esculentum to population density and emergence date
• 2.1 Introduction
• 2.2 Materials and methods
• 2.2.1 The Study Species
• 2.2.2 Experimental Design and Treatments
• 2.2.3 Data Analysis
• 2.3 Results
• 2.4 Discussion
• 2.4.1 Plasticity in architectural and biomass ratios in response to density
• 2.4.2 Plasticity in architectural and biomass ratios in response to sowing date
• 2.4.3 Magnitude of plasticity among treatments
• Chapter III Variation in branch length in the response of Fagopyrum esculentum to population density and sowing date: No evidence for optimality
• 3.1 Introduction
• 3.2 Materials and Methods
• 3.2.1 Specie description
• 3.2.2 Experimental design and Treatments
• 3.2.3 Data Analysis
• 3.3 Results
• 3.3.1 Allometric relationship between branch length and total biomass
• 3.4 Discussion
• 3.4.1 Change in branch length: optimality or size?
• Chapter IV Phenotypic plasticity in Datura stramonium in response to density and nutrient supply
• 4.1 Introduction
• 4.2 Materials and Methods
• 4.2.1 Brief description of the species
• 4.2.2 Study site and environmental conditions
• 4.2.3 Experimental design and treatments
• 4.2.4 Measurements.
• 4.2.5 Data analysis
• 4.3 Results
• 4.4 Discussion
• 3.4.1 Effect of density
• 3.4.2 Effect of nutrient supply
• Chapter V Plasticity in reproductive allocation in Datura in response to four environmental factors
• 5.1 Introduction
• 5.2 Materials and Methods
• 5.2.1 Study species
• 5.2.2 Study site and environmental conditions
• 5.2.3 Experimental design
• 5.2.4 Data analysis
• 5.3 Results
• 5.3.1 Allometric relationships
• 5.4 Discussions
• Chapter VI Phenotypic plasticity and its potential impact on grain production in two annual crop species
• 6.1 Introduction
• 6.2.1 Treatments and experimental design
• 6.2.2 Measurements
• 6.2.3 Data analysis
• 6.3 Results
• 6.4 Discussion
• 6.4.1 Pattern of plasticity and reproductive allocation in response to density
• 6.4.2 Consequences of the plasticity patterns on grain production
• 6.4.3 Some concluding remarks
• Chapter VII
• 7.1 General Conclusions
• 7.2 Suggestions for further research
• References
• Acknowledgements
• Publications from my thesis