中文摘要：

附生地衣是热带和亚热带山地森林生态系统中重要的结构性组分,在生物多样性保护、环境监测、养分循环中发挥着重要作用。附生地衣按共生藻、生活型和繁殖策略的不同可划分为不同的功能群,不同附生地衣功能群的分布格局存在较大的差异,然而其生理生态机制仍不清楚。该研究以我国西南地区哀牢山亚热带山地森林中的附生地衣优势类群为研究对象,对该地区蓝藻地衣、阔叶地衣、狭叶地衣及枝状地衣4种功能群的8种附生地衣的水分关系、光合生理特征等进行了测定分析,结果显示：不同功能群附生地衣的持水力和失水速率均存在差异,其中蓝藻地衣具有较高的最大水分含量,而枝状地衣的失水速率较快;过高和过低的水分含量都会抑制附生地衣的光合作用,但抑制程度有所差异;蓝藻地衣的光合作用最适水分含量比较高,表明它们的光合生理活动对水分条件要求较高,所以它们偏好潮湿的生境,同时蓝藻地衣的光补偿点比较低但光饱和点却不低,反映出它们具有较宽的光强适应范围,所以蓝藻地衣能够同时分布于强光和弱光生境中;枝状地衣的光合最适水分含量较低,表明它们的光合生理活动对水分条件要求不是很高,能够适应较为干旱的环境,同时枝状地衣的光补偿点和光饱和点都很高,说明它们的光合生理活动对光照条件要求比较高,所以它们广泛分布于强光生境中;阔叶和狭叶地衣的光补偿点比较高,说明它们更适应有充足光照条件的生境。

英文摘要：

Aims There are abundant epiphytic lichens in the tropical and subtropical montane forest ecosystems, which are important components of forest canopy and play a vital role in biodiversity conservation, environmental monitoring and nutrient cycling. In accordance with photobiont type, growth form and reproductive strategy, the epiphytic lichens can be divided into different functional groups, with different distribution patterns. In this study we aim to explain this phenomenon from the perspective of physiological ecology. Methods The maximum water content, water loss curves, photosynthetic water and light response curves were determined in four epiphytic lichen functional groups, including cyanolichens, fruticose lichens, broadly lobed foliose lichens and narrowly lobed foliose lichens. Important findings The functional characteristics of epiphytic lichens influence their maximum water-holding capacity and rate of water loss. The cyanolichens have higher maximum water content, while the fruticose lichens have a faster water loss. The cyanolichens that are widely distributed in the moist habitats require particularly high moisture for their photosynthetic activities; their optimal water content for photosynthesis is higher in comparison with other groups. They also have a low light compensation point and a high light saturation point, which explain the wide range of light intensity of the habitat. The fruticose lichens, widely distributed in the relatively arid habitats with high irradiance, have high light compensation point and light saturation point, and low optimum water content for photosynthesis. The broadly lobed foliose lichens and the narrowly lobed foliose lichens have a high light compensation point and light saturation point; they preferably occur in habitats with strong light.