海岸梯度上水杉叶片性状协同变化及其权衡机制

Effects of wind on plants and their adaptations are topics in shelter forest and ecology. At present, the response and adaptation of leaf physiological and morphological traits to wind stress have been revealed, while leaf stoichiometry, which dominants leaf physiological and morphological traits, and covariation among leaf traits are neglected. Based on our previous studies, we selected 12 Metasequoia glyptostroboides plots along coastal gradients, where wind damage decreases along coastal distance. First, we study the variations in leaf stiochioemtric traits, such as carbon, nitrogen, phosphorus concentrations and ratios of them, leaf physiological tratis, such as photosynthesis and tranpiration rates, and morphological, anatomic traits, clarify the response mechanism of leaf traits to wind load, and explore the effects of stoichiometry on physiology and morphology. Second, we study the covariation among these leaf traits, and explore the mechanisms of leaf traits trade-off according to environmental and biological factors. Here, we want to verify covariation and trade-off among leaf traits under wind loads, which is help to understanding the adaption stratages of leaf and "thigmomomhogenesis", and to improving the knowledge of tree and wind.

风对植物的影响和植物的适应策略是当前防护林学和生态学研究的热点问题。目前，植物对风的适应研究主要集中在生理和形态性状的描述方面，忽略了叶片化学性状以及性状间协同变化的适应机制。在已有研究的基础上，本项目基于不同海岸距离形成的风害差异，以海岸梯度上12个水杉样地为研究对象，结合长期定位监测，研究海岸梯度上不同生长季节水杉叶片碳、氮、磷含量及比值等化学计量性状，光合、蒸腾速率等生理性状和长度、宽度、比叶面积等形态结构性状的变化规律，解析叶片性状对风胁迫的响应机制，探究叶片化学性状对生理和形态结构性状的影响；研究海岸梯度上叶片性状间的协同变化关系，结合生物群落与环境因子，分析叶片性状间协同关系的内在和外在机制。本研究旨在探明海岸梯度上叶片性状间的协同变化和权衡机制，补充完善叶片对风胁迫的响应与适应机制和“向触性形态建成”，有助于深化我们对树木与风关系的认知。

海岸梯度上风胁迫强度与频率均呈现出时空变化特征，随着离海岸距离的增加，风速逐渐降低，从而形成不同程度的风胁迫生境。风主要从改变树木周围气场环境和增强机械刺激来影响林木的功能性状，特别是光合器官叶片功能性状，从而引起叶片产生“向触性形态建成”（thigmomorphogenesis）。前期已有大量模拟控制实验研究风对植物的影响，但长期自然风环境下的研究仍显不足。基于此，本研究以滨海水杉林为研究对象，设置3条与海岸线垂直，间距700m的样线。结果显示：1）风胁迫对水杉叶片化学计量与形态指标的影响不同；2）风胁迫下水杉叶片与土壤化学计量关系不密切，化学计量内稳性可能受到了一定的影响；3）海岸梯度上水杉叶片形态、生理与化学计量之间表现出协同变化关系。总的来看，项目围绕海岸梯度上水杉叶片N、P计量特征与树木形态、生理等建立了一定的联系，风环境中水杉的化学性状对形态建成有重要的调控作用，研究结果为揭示沿海防护林抵抗风害的生态适应性策略提供了科技支撑。