河西荒漠区典型灌木繁殖物候响应降水的机制

Precipitation is a central enabler in water-limited arid desert ecosystem, whose pattern and intensity may have an important impact on reproductive phenology in desert plants. However, our knowledge of the influence of natural or abnormal precipitation on reproductive phenology among different communities, species and populations remains limited in Hexi desert area. There is a need for a more thorough exploration of the ecological mechanisms underlying how precipitation affects phenological characters and the diversity of reproductive adapting strategies. In this study, we used common shrubs in a typical arid desert shrubland in Hexi Corridor of Gansu province as a research system. By means of field investigations, multi-scale manipulations, laboratory experiments, and theoretical analyses, we address the three key questions: (1) the responses of reproductive phenological characters in several typical shrubs to natural precipitation; (2) the effects of precipitation addition and reduction and natrual precipitation on reproductive phenology; (3) the possible mechanisms underlying how precipitation patterns and intensity affect reproductive phenological characters in desert shrubs. Our aims of this study are to determine underlying mechanisms of how changes in environmental conditions and individual traits driven by precipitation affects reproductive phenology, to analysis the reproductive adapting strategies and its ecological significance in the face of incontinuous and uncertain precipitation in typical desert shrubs. The findings may provide scientific evidence for maintaining dynamic balance of plant populations and communities, and for the conservation and restoration of natural ecosystem in Hexi desert area.

降水是干旱荒漠生态系统的核心驱动力，其格局与强度的变化深刻地影响着荒漠植物的繁殖物候特征。目前对干旱区降水如何影响和调控植物繁殖物候及其适应多样性形成和维持的生态机制与意义的认识还非常有限。本项目以甘肃河西走廊干旱区常见的荒漠灌木为研究对象，通过对野外典型群落的自然观测和多尺度控制实验，结合室内分析和理论分析，重点研究：⑴河西走廊干旱荒漠区典型灌木的繁殖物候特征；⑵干旱区荒漠灌木的繁殖物候对降水变化的响应规律；⑶降水事件影响荒漠灌木繁殖物候的调控机理。通过研究，揭示降水驱动下的环境因子及个体性状变化对其繁殖物候的调节机制，解析植物对间断且不可预测的干旱区降水环境的繁殖适应对策与其生态意义。研究结果将为维持干旱区植物种群与群落的动态平衡，保护和恢复河西荒漠地区的自然生态系统提供理论依据。

降水是干旱荒漠生态系统的核心驱动力，其格局与强度的变化深刻地影响着荒漠植物的繁殖物候特征。目前对干旱区降水如何影响和调控植物繁殖物候及其适应多样性形成和维持的生态机制与意义的认识还非常有限。本项目以甘肃河西走廊干旱区常见荒漠灌木为研究对象，通过野外典型群落的自然观测和多尺度控制实验，结合室内分析和理论分析，重点研究：⑴干旱荒漠区典型灌木植物的繁殖物候特征；⑵模拟增雨与模拟干旱对荒漠灌木繁殖物候的影响；⑶降水影响荒漠灌木繁殖物候特征的具体调控过程。研究发现梭梭和泡泡刺的繁殖物候对水文过程改变的响应不明显，其盛花期与花期持续时间主要受个体大小的影响。而沙拐枣的开花物候和花部结构等繁殖特征能够对人工增水处理做出响应，根据环境中水分条件的变化灵活地调整其功能形态特征。降水量的增加将改变沙拐枣的开花物候特征，延长花期持续时间，提高种子产量；增水处理或提高土壤湿度，将改变沙拐枣的花部结构特征，使个体更倾向于异交；而在降水较少的干旱环境中，沙拐枣个体更倾向于自交，增加繁殖效率，弥补环境中传粉昆虫的不足，提高适合度。