自然干旱下彰武小钻杨幼苗生态化学计量变化规律OA北大核心CSTPCD

To understand the variations of nutrients and stoichiometric ratios in Populus × xiaozhuanica cv.Zhang-wu seedlings under drought stress,we grew the seedlings in pots under a condition of continuous natural drought.Carbon(C),nitrogen(N),phosphorus(P),and potassium(K)contents in different organs(leaf,stem,root)were measured at 0,6,12,18 and 24 days after drought,and the correlations of elements among organs were ana-lyzed.Results showed that N and K contents and C∶P and N∶P decreased but P content and C∶N and C∶K increased in all organs after 6 days of the drought.N content and C∶P and N∶P increased but P content de-creased in all organs when the drought lasted from the 6th day to the 12th day.Root C content,C∶N,C∶P and C∶K showed downward trends when the drought lasted from the 12th day to the 24th day.Under continuous drought treatment,there were significant positive correlations in N or P content among leaves,stems,and roots,as well as C content between leaves and stems,and K content between leaves and roots.P.× xiaozhuanica cv.Zhang-wu seedlings could adjust the stoichiometry of C,N,P,and K in various organs to adapt to the gradually intensi-fied drought stress.First,C supply for roots increased,K transferred from stems to leaves and roots,and N content in each organ increased to resist drought stress.Finally,C supply for roots decreased,N consumption increased,and P and K accumulated in the seedlings.