我国云杉属树种对气候变化的生理生态响应和适应机制研究

Species of the genus Picea (spruce) are the important forest construction species and afforestation tree species in north of China, understanding about how they will respond to ongoing climate change is crucial to the sustainable development and scientific management of northern forest ecosystems. However, there is still a lack of systematic studies on response of spruces species to high temperature, drought and their interaction effects. Therefore, it is of great value to study the ecophysiological responses and adaptive mechanisms for high temperature, drought and their interaction in spruce species of China based on the xylem hydraulic structure as the key traits. In this project, we will use seven-years old seedlings of 12 members of spruce tree species mainly distributed in China to examine the single and interactive effects of high temperature and drought on morphological, physiological and growth traits through artificial simulation control experiments (elevated temperature, drought, and interactive treatment). The measured traits include xylem hydraulic characteristics, twig water relations, leaf gas exchange, leaf chlorophyll fluorescence, leaf nitrogen element content (N), carbon isotope composition (δ13C), growth and some other biochemical parameters. Our aims are to explore the impact of climate change on the growth of spruce tree species, to reveal ecophysiological mechanism of spruces tree species to response of future climate change from the aspects of xylem hydraulic structure characteristics, twig water relations and leaf gas exchanges, to evaluate the ability of spruce species to adapt to climate change in future, to comprehensively elucidate how spruce tree species would response to different climate change scenarios in future. This project will help us to provide scientific bases and supports on spruce tree species breeding and sustainable development of spruce forests in China.

云杉属树种是我国北方重要的森林建群种和人工造林树种，研究其如何响应气候变化对于北方森林的可持续发展及科学管理具有重要意义。但目前有关云杉属树种对气候变化，特别是对高温、干旱胁迫及互交互作用响应还缺乏系统的研究，因此开展基于木质部水力结构为关键性状的我国云杉属树种对高温、干旱及交互作用的生理生态响应和适应机制研究具有重要价值。本项目拟以我国主要分布的12种云杉幼树为研究对象，通过人工模拟控制实验(增温、干旱及交互处理)测定木质部水力结构特性、枝叶水分关系、光合能力和生长状况等指标，探讨气候变化对云杉树种生长的影响，从木质部水力结构、枝叶水分关系、光合能力等方面揭示云杉树种对未来气候变化的生理生态响应机制，全面评价云杉树种对气候变化的适应能力；并结合不同气候区的2处野外同质园对比验证，全方面阐释云杉树种对未来不同气候变化情景的响应规律，为未来云杉树种选育和云杉林可持续发展提供理论支撑。

云杉属树种是我国北方重要的森林建群种和人工造林树种，研究其如何响应气候变化对于北方森林的可持续发展及科学管理具有重要意义。本项目以我国主要分布的云杉树种为研究对象，利用人工模拟控制土壤水分和温度实验，通过测定云杉属树种当年生枝叶气体交换参数、荧光参数、水分关系和生理生化等指标，分析了云杉属树种对高温、干旱的生理生态响应差异，评价了各树种对气候变化的适应能力，结合2处不同生长环境的野外同质园调查，对比了云杉属各树种的生长状况和生理生化指标的表现。结果表明，1）干旱胁迫导致云杉属树种光系统II反应中心活性下降，从而降低了云杉属各树种的光合能力，而光系统II最大活性则取决于各树种在干旱条件下的水分状况。2）长期增温主要导致云杉属树种光系统II受体侧的光能吸收、转换、电子传递过程的活性下降。3）野外同质园对比观测，进一步证实干热生长环境会抑制云杉属树种的生长。4）控制实验和野外同质园对比分析表明，青海云杉具有较强的抗干旱和高温能力。5）利用Maxent模型明确了影响青海云杉分布的主导气候因子，探讨了不同气候变化情景下青海云杉潜在分布区的变化。6）此外，作为项目的合理拓展，通过数据整合，分析了云杉属树种非结构碳含量及组分对温度变化的响应，揭示了云杉属树种枝叶表型性状与非结构性碳水化合物间存在权衡关系，分析了云杉属树种细胞抗水分丧失能力与非结构性碳间的关系，探讨了云杉属树种当年生枝叶细胞渗透调节能力差异产生的原因，建立了云杉属树种夏季高温和冬季低温时的转录组数据库，初步分析了云杉属树种在高温和低温生长情况下的表达差异。本项目研究成果不仅对深刻理解全球气候变化对北方温带、寒温带高山、亚高山地区暗针叶林带来的影响具有重要意义, 还为将来云杉属良种选育和云杉林可持续健康发展提供理论基础和支撑。