Abstract:
The water absorption capacity, water release, desiccation tolerance,stable carbon isotope (δ
13C) values, and effects of water content change on photosynthetic and fluorescence parameters of four bole epiphytic bryophytes,
Plagiochila assamica Steph.,
Homaliodendron montagneanum (Müll. Hal.) M. Fleisch.,
H. scalpellifolium (Mitt.) M. Fleisch., and
Thuidium cymbifolium (Dozy et Molk.) Dozy et Molk., were investigated from the montane moist evergreen broad-leaved forest of the Ailao Mountains, Yunnan, China. Results showed that:(1) all species had high water absorption rates, low water-holding capacities, and strong desiccation tolerances, and all exhibited quick resilience after dehydration; (2) the δ
13C values and water use efficiency of the four bryophytes were lower than those of vascular plants. Except for
T. cymbifolium, the δ
13C values and water use efficiency of the other three bryophytes in the rainy season were higher than those in the dry season; and (3) the net photosynthetic rates (
Pn) of the four epiphytic bryophytes declined with decreasing water content. The maximum photochemical efficiency parameter (
Fv/
Fm) declined sharply under water content conditions of less than 60%~80%, indicating that the photosynthetic and fluorescence properties of the four bryophytes were very sensitive to moisture change.