基于代谢生态学的植物对海拔梯度的适应：功能性状、生物量和温度的耦合

Understanding the mechanisms of plant adaptation to the environmental gradients is the base for explaining and predicting the ecosystem response to the future global environmental change. Studies have shown that plant leaf and stem traits, biomass and ecosystem structure would vary as mean temperature declines with latitude. However, knowlede of such variations and their synergistic effects on plant adaptation remains limited. The impact of rising temperature is more pronounced in tropic ecosystems than in other ecosystems. Because the adaptation of a plant to latitude is embodied in its metabolic rate community resource use, this research project aims to build a new metabolic model from the existing metabolic theory by coupling it with plant adaptation to latitude, with a particular emphasis on the mechanisms of adaptation of subtropic plants to latitude. To empirically test the model, the project will examine the separate and synergistic effects of plant branching structures, leaf and stem traits, and biomass on plant adaptation to latitude in subtropical Wuyi mountain, which includes subtropical evergreen broad forest, mixed broad and needle forest, needle forest, dwarf forest and alpine meadow. Results would expand the scale and scope in research of the metabolic theory of ecology, shed new insights into how synergistic effects of functional traits (e.g. leaf traits, branching architecture) and biomass modulate plant adaptation to altitude, and improve the predictability of the change of plant functional traits in the context of global warming and provide a theoretical basis for the management of moist subtropical mountain ecosystems.

研究植物对环境梯度的适应机制是阐释和预测生态系统对未来气候变化响应的基础。随着海拔的升高,温度降低，植物叶片性状、生物量和群落组成等均发生改变，但这些适应过程的综合效应对植物个体适应及群落资源利用的影响机理尚不清楚；另外，气候变暖对热带（含亚热带）生态系统的影响也高于其他地区，因此，急需开展该区域的植物环境适应研究。本项目拟基于代谢生态常理论开展植物对海拔的适应研究，通过构建包含植物功能性状（分支结构，叶、茎性状）、生物量与温度的代谢模型，耦合代谢生态学与植物性状的海拔变化研究，重点突破亚热带植物的海拔梯度适应机制；以新模型为理论框架，选择武夷山不同植被类型为研究对象，阐释功能性状、生物量及其综合效应对亚热带植物海拔梯度（温度）适应的影响。项目结果将有助于拓展代谢生态学的研究内涵，提高全球变暖背景下植物功能对环境变化响应与适应的预测能力，为湿润亚热带山地系统的适应性管理提供理论依据。

认识和了解植物对环境的适应机制是阐明和预测陆地生态系统对未来环境变化的基础。本项目以代谢生态学为基础，对武夷山不同海拔山地植物的环境适应机制等进行研究。同时，对全球尺度的森林生态系统净初级生产力的调控机制进行了分析，取得的原创性结果主要有：（1）全球尺度上，气候因子主要通过调控群落结构来间接影响群落生产力；（2）武夷山木本植物当年生小枝生物量分配成等速生长关系，且这种等速生长不因群落类型和海拔发生变化；（3）小枝叶生物量与叶数量之间存在权衡关系，其控制因素是茎的代谢速率；（4）山地植物不同器官的N:P调控因素不同，叶片N:P主要受到N含量的影响，而其它器官N:P则受到了N、P元素的共同制约；（5）不同海拔，不同竹种均存在叶面积与叶质量的异速生长关系，表明随着叶大小的增加，叶片收益存在递减现象。本项目拓展了代谢生态学的研究内涵，提高了全球变暖背景下山地植物功能对环境变化响应与适应的预测能力，为湿润亚热带山地系统的适应性管理提供理论依据。项目发表论文24篇，其中包括在Nature，Annals of Botany等发表的SCI论文9篇，中文期刊15篇。还有重要研究成果将陆续整理发表。