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

Nutrient content and nitrogen and phosphorus reabsorption characteristics of dominanttree species in the broad-leaved Korean pine forest in Jiaohe, Jilin Province

以吉林蛟河阔叶红松林常绿乔木(红松)和3种落叶乔木(蒙古栎、紫椴和色木槭)为研究对象,采集4种乔木成熟叶与衰老叶,测量其碳(C)、氮(N)、磷(P)含量,并计算其化学计量比和养分再吸收效率,分析不同生活型乔木叶片养分含量、化学计量比和养分再吸收效率的差异,研究不同生活型乔木养分保存机制。结果表明:(1)落叶乔木叶片N、P含量显著高于红松,衰老叶N含量差异不显著。(2)红松成熟叶C∶N、C∶P显著高于落叶乔木,红松衰老叶C∶N显著高于落叶乔木,不同生活型乔木叶片N∶P没有显著差异。(3)落叶乔木N再吸收效率(NRE)和P再吸收效率(PRE)显著高于红松;乔木叶片NRE/PRE比值均大于1。(4)乔木成熟叶N、P含量均与NRE和PRE呈显著正相关关系,衰老叶C∶N和C∶P均与NRE和PRE呈显著负相关关系。总之,吉林蛟河阔叶红松林4种乔木成熟叶养分含量会影响其养分再吸收效率,衰老叶C∶N和C∶P可以反映其养分再吸收效率,4种乔木均更倾向于从衰老叶片中吸收N。

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 senescent leaves were measured,and their stoichiometry and nutrient resorption efficiency were calculated.The differences 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 significant 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 species showing a preference for absorbing N from senescent leaves.