Stoichiometrical characteristics of nitrogen and phosphorus in leaves of three plants from fencing area of sub-alpine meadow

JIA Yun;LIU Min-xia;CHEN Shi-wei;AN Yan-fei;AN Qi;College of Geography and Environmental Science,Northwest Normal University;

nitrogen of leaf;;phosphorus of leaf;;N∶P;;fencing;;sub-alpine meadow

Nitrogen(N)and phosphorous(P)are the main restrictive elements of the terrestrial ecosystems,and they also act very important roles to the growing of plants.We discussed the stoichiometrical characteristics of nitrogen and phosphorus in three plant leaves and their relationship to the soil contents in the enclosed area of sub-alpine meadow located in the northeast of Qinghai-Tibet Plateau.The results showed that variable coefficients of leaf N in Artemisia tangutica and Elymus dahuricus were 14.9% and24.34%respectively,which were 8.12% and 20.90% higher than that of leaf P,and this showed that leaf N was more flexible than leaf P.On the contrary,the variable coefficient of leaf N(12.56%)was lower than that of leaf P(14.49%)in Medicago sativa.The N and P contents of Artemisia tanguticaand Elymus dahuricus were all differed significantly among three sample areas(P<0.05,and the P content of Medicago sativaalso shows significant difference(P<0.01).This showed that nutrient contents of plant leaves weresignificantly different among different sample areas.The leaf N and P contents of Artemisia tangutica and Elymus dahuricus were both significantly positively related to soil N and P(P<0.05).Leaf N of Medicago sativadid not significantly related to soil nutrient content,while the N∶P ratio of its leaf had significantly negative correlation with soil P concentration(P<0.05).This suggested that in sample areas,Artemisia tangutica and Elymus dahuricus were inclined to be influenced by soil N and P,while Medicago sativa was more inclined to be influenced by P.This study could provide basic information for the biodiversity protection and vegetation restoration of study region.