附生植物是山地森林生态系统中多样性最高、最为敏感脆弱的类群之一，在森林生态系统的碳、水和养分循环过程中发挥着重要作用。空气中的水分供应状况是决定附生植物组成和分布的关键因素。然而，在区域干旱加剧的气候背景下，关于附生植物的水分关系及其对干旱胁迫的响应机制却鲜有研究。本项目以哀牢山湿性常绿阔叶林常见附生植物为研究对象，基于林冠塔吊平台和人工气候室，采用氢、氧、碳稳定同位素技术、定位监测和人工控水实验相结合的方法，研究不同类群附生植物叶片形态、结构和生理功能性状各项指标的异同及其相互作用关系，探讨各类附生植物的水分来源、比例及其季节变化特征，定量评估其长期光合水分利用效率，阐明不同类群附生植物的水分关系，揭示附生植物对干旱胁迫的生理响应机制。研究结果为深入研究山地森林生态系统碳、水循环，以及全球变化背景下生物多样性的保护和利用提供科学依据。

Epiphytes comprise one of the most diverse, but also the most vulnerable component in montane moist forest ecosystems, and they are extremely important in carbon, water and nutrient cycling in these ecosystems. Water supply is the key factor affecting the composition and distribution of epiphytes. Increased drought is likely to become the most detrimental aspect of climate change for epiphytes that live in montane moist forests. However, water relations of epiphytes and their response mechanisms to drought stress were rarely studied. In this project, both field and laboratory experiments will be conducted to characterize the leaf morphology, structure, and physiological functional traits of different groups of epiphytes in the montane moist evergreen broad-leaved forest in Ailao Mountains. Long-term water use efficiency, the relative contributions of different water sources and their seasonal variations will be quantitatively evaluated by using stable isotope technique (stable carbon, hydrogen and oxygen isotopes). The response mechanisms of epiphytes to drought stress will be revealed based on in situ monitoring (canopy crane), together with a simulated drought experiment (closed-top chambers). The information generated from this project will provide scientific basis for understanding carbon and nitrogen cycling of the montane moist forest ecosystems, as well as protection and utilization of biodiversity in a changing world.