吉林蛟河阔叶红松林主要树种叶片养分含量及氮磷再吸收特征OACSTPCD

In this study,four species in the broad-Korean pine forest located in Jiaohe,Jilin Province,i.e.one evergreen tree(Pinus koraiensis)and three deciduous trees(Quercus mongolica,Tilia amurensis and Acer mono)were taken as the objects,their carbon(C),nitrogen(N),and phosphorus(P)contents in their mature and senes-cent leaves were measured,and their stoichiometry and nutrient resorption efficiency were calculated.The differ-ences in nutrient content,stoichiometry,and nutrient reabsorption efficiency among leaves of different tree life forms were also analyzed,thereby to investigate the nutrient conservation mechanisms of these trees.The results were as follows.(1)The N and P levels in the leaves of deciduous trees were significantly greater compared to those of Pinus koraiensis.(2)The ratios of C to N and C to P of P.koraiensis mature leaves were significantly higher than those of the deciduous trees.Additionally,the ratio of C to N in the senescent leaves of P.koraiensis was significantly higher than that of the deciduous trees.There was no significant difference in N∶P ratio among the leaves of different tree life forms.(3)The reabsorption efficiency of nitrogen(NRE)and phosphorus(PRE)of the deciduous trees were both significantly higher than those of the P.koraiensis.The ratio of NRE/PRE in the tree leaves was greater than 1.(4)The N and P contents in the mature leaves of trees exhibited significant positive correlations with NRE and PRE.Conversely,the C∶N and C∶P contents in the senescent leaves showed signifi-cant negative correlations with NRE and PRE.In conclusion,the nutrient contents of the mature leaves of the four species affect their nutrient reabsorption efficiency in the broad-leaved Korean pine forest in Jiaohe,Jilin Province.C∶N and C∶P ratios in the senescent leaves may reflect their nutrient reabsorption efficiency,with all four spe-cies showing a preference for absorbing N from senescent leaves.