兰属(Cymbidium)植物为中国传统名花，其中2/3的种类是生于树干上的附生兰。因附生环境缺少缓冲基质，附生植物对干扰和环境变化敏感。事实上，人类活动及环境变化正使兰属植物种群承受着巨大的生存压力，生态适应性的研究将有助于更好地保护和利用好这些珍贵资源。水分被认为是影响附生植物生长存活的关键环境因素，但相关的生理生态机制仍不清楚。项目将利用野外及控制实验，通过对兰属附生种与地生种的比较，从分子、生理和形态多个层次，研究(i)各种水源(雨水、雾水、植物自身储水)在旱季对兰属附生植物生理功能维持的相对贡献；(ii)兰属附生植物响应水分胁迫的分子、生理及形态策略；(iii)水力结构及碳平衡对兰属附生植物在干旱胁迫中存活的影响，进而阐明兰属附生植物的水分适应特征，为种质资源的保护利用提供科学依据。发表SCI论文6篇，培养研究生2名。

Cymbidium, known as "Chinese orchid", is one of the traditional famous flowers in China. About 2/3 Cymbidium species are epiphytes, growing on the stems and branches of trees. As lack of buffer medium in epiphytic habitats, epiphytes are usually more sensitive to disturbance and environmental change than terrestrial plants. In fact, human activity and environmental change (especially precipitation) exert unprecedented stresses on the natural populations of Cymbidium. Water stress is considered to be a primary factor affecting the population dynamics of epiphytes. However, the ecophysiological mechanisms whereby how water stress affects the growth and survival of epiphyte remain unclear. The present project will compare the differences in molecular, physiological and morphological adaptations to water availability between epiphytic and terrestrial species in Cymbidium by field investigations and controlled experiments. The main objectives are to understand: (i) the relative contributions of various water sources (rainfall, fog, storage water in plant organs) to the maintenance of physiological functions in epiphytic Cymbidium in the rainy and dry seasons; (ii) the morphological, physiological and molecular adaptations of epiphytic Cymbidium to water stress; (iii) the relative roles of plant hydraulics and carbon balance in the growth and survival of epiphytic Cymbidium during drought period. This project will illustrate the adaptive mechanisms of epiphytic Cymbidium to water availability, and provide valuable knowledge for the conservation and utilization of Cymbidium germplasm. 6 SCI papers will be published and 2 graduate students will get trained through implementing the project.