喀斯特地区不同光合型植物在不同CO2浓度下对干旱胁迫的生态适应

项目名称： 喀斯特地区不同光合型植物在不同CO2浓度下对干旱胁迫的生态适应

项目编号： No.31500399

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 生物科学

项目作者： 刘锦春

作者单位： 西南大学

项目金额： 20万元

中文摘要： 西南喀斯特地区干旱频发和大气CO2浓度升高，直接影响植物个体的生理和生长，改变群落演替动态，影响生态系统生产力和碳循环。本项目模拟末次盛冰期、目前和本世纪末3种CO2浓度条件，从植物的生长和生物量积累、植物功能性状、光合生理调节和资源整合及分配四个方面，通过比较研究三种不同光合型（C3、C4、CAM）植物在不同水分条件下对CO2浓度变化（降低和升高）的响应程度，探索植物在“将来”时间上的生态适应和在“过去”时间上的进化关系；通过比较三种不同光合型植物在不同CO2浓度条件下对干旱胁迫的生态响应差异，探索适应喀斯特干旱生境的光合类型及其适应机制。最终验证科学假设“由于不同光合型植物对低CO2浓度的进化适应程度不同导致了其对高CO2浓度的生长和生理响应的差异，C4和CAM植物比C3植物更能适应喀斯特地区的干旱生境”。研究结果将对预测喀斯特生态系统动态进程和探讨全球碳循环具有重要的理论和现实意义。

中文关键词： CO2浓度富集；生理响应；全球变化；适应进化；响应

英文摘要： The Karst landscape, very widespread in the world, features periodic soil water limitation. Atmospheric CO2 concentration is predicted to rise to up to 700 ppm by 2100 as a result of fossil fuel combustion and deforestation. Water availability and atmospheric CO2 concentration has profound effects on plant evolution, adaptation and primary productivity. Plant adaptation to CO2 in return will affect carbon cycling through assimilation and respiration. The growth of modern plants may still be constrained by their evolutionary adaptations to combinations of low atmospheric CO2 concentration of past glacial periods and these constraints may also limit growth responses to rising CO2. Such responses may also interact with the plants’ responses to water availability in karst system. C3, C4 and CAM plants, might have different responses to the interaction of CO2 variation and water availability due to their different photosynthesis types. Thus, for predicting plant and vegetation responses to future climate change it is important to study interactive effects of water availability and rising CO2 from glacial to modern and future concentrations on growth and physiological traits of different photosynthesis types. We plan to study morphological, growth and physiological traits responses of 6 temperate species (including C3, C4 and CAM species), to glacial, modern and future CO2 concentration and three soil water availability regimes in walk-in chambers, to test the following scientific questions: (1) How might evolutionary adaptation to past glacial CO2 variation be significant for phenotypic responses of plants to high levels of CO2 in the future? Could the relationship be modulated by water availability? (2) Which type(s) among C3, C4 and CAM plants will be more suitable to water shortage under CO2 concentration variation in karst system, and the underlying mechanisms? The results will provide valuable insights of predicting plants’ future responses to a rapidly changing environment, and evaluating the consequences for the global carbon cycling in karst system.

英文关键词： CO2 increased;physiological response;global change;adaptive evolution;response