Comparison of water absorption characteristic and water retention capacity of five epilithic mosses in the karst areas of Guizhou Province

In order to provide a theoretical basis for the water cycle and rocky desertification control of karst ecosystems, this paper studies the water retention and absorption abilities of five moss species, i.e. Erythrodontium julaceum, Barbula unguiculata, Bryum argenteum, Eurohypnum leptothollum and Racomitrium japonicum, which are commonly seen in the rocky desertification area of Puding, Guizhou Province. The results show that, the reserve mass of five epilithic mosses ranges from 0.71 t?hm-2 to 3.91 t·hm-2 , with the largest reserve of 3.91t·hm-2 for E. julaceum.The highest water retention capacity is 761.9% for R. japonicum, E. leptothollum is the second of 653.8%,and the smallest is 551.7% for B. argenteum. E. julaceum and E. leptothollum are the dominant species with the highest water retention capacity .The highest water retention rate was 38.2% for E. leptothollum, R. japonicum ia the second of 33.6% and the lowest is 15.2% for B. argenteum. The water absorption processes of the five mosses include two ways, i.e. external and internal water absorptions. There are differences in the time of water absorption and saturation for the moss species. Five species had the same water absorption dynamic reflected by the S type saturation curve. When the water content is below 25 g, the water absorption rate of the plants is directly proportional to the amount of water added. When the external water content increases to or above 25 g, the water absorption rate of the plants gradually trends to reach the maximum.