Study On The Relationship Between Stoichiometric Homeostasis And Stability Of Forest Ecosystem Invaded By Moso Bamboo

As a clonal plant,Moso Bamboo has been invaded rapidly neighbour forests with its strong rhizome growth capacity,and resulted in declining of the plant diversity.In order to explore the mechanism of invasion surrounding forest by bamboo,the C,N,and P contents of plants including Pinus massoniana,Schima superba,Elaeocarpus sylvestris,Cyclobalanopsis glauca,Castanopsis sclerophylla,and Phyllostachys edulis and soils were measured based on stoichiometric characteristic,and the C,N,and P stoichiometry characteristics and relationship between plants and soils were analyzed in this dissertation.At the same time,the C,N,and P contents of plants and soils were measured to anlayze relationship between plants and soils respectively,and to explore their stoichiometric stability and influencing factors as well as relationship of bamboo invasion using pots and field experiments.The pot plants including Cunninghamia Lanceolata,Schima superba,Cyclobalanopsis glauca,and Castanopsis sclerophylla and the field plants including Schima superba and Elaeocarpus sylvestris were added the different contents of N and P three times during 240 days.The results showed:(1)The C contents of Phyllostachys edulis leaves were significantly lower than that of dominate tree species at different succession stages.However,the N contents of Phyllostachys edulis leaves were significantly higher than that of dominate tree species at different succession stages.There were no difference between the P contents of Phyllostachys edulis leaves and other dominate tree species.Copared with other dominate tree species,the C:N and C:P ratio of Phyllostachys edulis leaves were least.Phyllostachys edulis and dominate tree species strongly needed N.There were linear positive correlation between the N,P,and N:P of plants and that of soils respectively.(2)The C contents of the bamboo shoots and Phyllostachys edulis at different growth stages were low.The bamboo from shoots to stem elongation needed more N and P than the bamboo from young to old.Along with the growth of bamboo,the ratio C:N and C:P were gradually increased.The bamboos were shortage of N in the growth process.(3)In N and P added experiment,the stoichiometric stability indexes of both pot plants and field plants were lower than that Phyllostachys edulis under the same treatments.Along with the growth of plants,their stability index HN were gradually increased.The relationships between the above and underground were opposite.For example,along with N addition,the stability index of Cyclobalanopsis glauca and Castanopsis sclerophylla roots were gradually decreased in pot experiments.However,the stability index of Cyclobalanopsis glauca and Castanopsis sclerophylla leaves were increased arranging in the first and second.The stability index of Cunninghamia Lanceolata and Schima superba roots were gradually increased in pot experiments while that of their leaves were decreased.The stability index HN of plants were higher than the stability index Hp of plants.