The Grimmia pilifera is a typical drought-tolerant saxicolous moss species， and the water is the key factor influencing its survival and reproduction. To explore the effects of micro-habitats to water physiology of G.pilifera， three typical micro-habitats（habitat S-1 is the bare rock shaded by bamboo individuals； habitat E is the exposed rock； habitat S-2 is the bare rock shaded by shrub Ficus pumila） were chosen in the Dalongshan National Forest Park in Anhui Province， then the differences in individual plant size， saturated water content and water content indices of G.pilifera during dehydration in different micro-habitats， and finally the impact of micro-habitats on moss water stress tolerance and trade-off characteristics were comprehensively assessed. It was found that the plant size and saturated water content indices varied significantly among three micro-habitats； there into， the moss plant size in habitat S-1 was low but the internal and external water contents were relatively high； the plant sizes and external water contents in habitat E and habitat S-2 were similar but the external water content was much more higher of the former. The external water contents of moss plants in the two shaded habitats S-1 and S-2 were seven times the internal water contents， and their ratios were notably higher than that in habitat E. The water content indices of G.pilifera in habitat E the same time during dehydration were higher than that in the two shaded habitats， and the time differences reaching the same water content gradually expanded as the dehydration proceeded； thus it won more time for moss plants in habitat E to carry out effective photosynthesis（here the relative water content is not less than 35%） and physiological and structural adjustment during the later dehydration. In total， G.pilifera plants in exposed rocks represented much stronger water stress tolerance than that in shaded rocks， but the later was able to increase the external water to make up the deficiency of rapid water loss. This might be the trade-off strategy of water absorption and retention for G.pilifera lived in different micro-habitats.
%U https://bbr.nefu.edu.cn/EN/10.7525/j.issn.1673-5102.2021.02.005