Nurse Effect Of Cushion Plant On Functioning And Diversity Of Soil Microbial Communities In Alpine Areas

Nurse effect,as the main factor which influences the community structure,plays a crucial role in the interactions among alpine species.Nurse plants facilitate other species through multiple ways,such as changing micro-environment,improving nutrition supply or eliminating competitors.Cushion plants are common nurse plants in alpine areas,which can provide refuges through their canopies to facilitate other plants growth.However,the nurse effect of cushions on underground soil microbes is seldom studied.This research devotes to explore the cushions(Thylacospermum caespitosum and Arenaria polytrichoides)nurse effect on soil microbial functional and structural diversity by Biolog technique and phospholipid fatty acid(PLFA)in four different sampling sites(Shibaocheng of Qilian Mountain,Tianshan No.l Glacier,Simala Mountain of Tibet,Mila Mountain of Tibet).The results of the study are as follows:1.The soil microbial activities were different among mountains.In the study,the soil microbial activities and biomass were higher in Simala Mountain of Tibet than Shibaocheng of Qilian Mountain.2.Cushion plants increased microbial activities and biomass.Thylacospermum caespitosum in Shibaocheng of Qilian Mountain and Arenaria polytrichoides in Simala Mountain of Tibet increased microbial biomass.Thylacospermum caespitosum improved microbial ativities,and the impact was higher in Shibaocheng of Qilian Mountain than Tianshan No.1 Glacier.3.Cushion plants improved the soil microbial functional diversity.Shannon-Wiener index and McIntosh index were higher inside cushions than bares.The utilizations of Amino acids,Esters and Acids were significantly higher inside cushions than bares.4.Cushion plants changed the soil microbial structural diversity.The contents of soil microbial groups were different between intra-and ex-cushions,Thylacospermum caespitosum in Shibaocheng of Qilian Mountain improved fungi and actinomyces contents and Arenaria polytrichoides in Simala Mountain of Tibet improved bacteria,actinomyces and gram positive bacteria contents.All above demonstrated that cushion plants improved soil microbial activities and changed soil microbial structure and composition,and this change was species-specific and context-depended.This study focused on the strategy that how soil microbes responded to cushions,which lays the basis for further exploring cushions nurse effect.This also helps to realize the important role which cushion plants played in the community formation and construction.