Tradeoffs of nitrogen investment between leaf resorption and photosynthesis across soil fertility in Quercus mongolica seedlings during the hardening period  

作　　者：Zexia Dong Jiaxi Wang Jingfei Chen Guolei Li Yong Liu Yining Li Yufan Zhu Xiaoqian Meng 

机构地区：[1]Research Center of Deciduous Oaks,Beijing Forestry University,Beijing 100083,People’s Republic of China [2]Key Laboratory for Silviculture and Conservation,Ministry of Education,Beijing Forestry University,Beijing 100083,People’s Republic of China [3]Yiwu Landscaping Greening Bureau,Yiwu City 322000,People’s Republic of China [4]Beijing Xishan Experimental Forest Farm,Beijing 100095,People’s Republic of China

出　　处：《Journal of Forestry Research》2024年第6期185-197,共13页林业研究（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.32171764,No.32101503);the 5·5 Engineering Research&Innovation Team Project at the Beijing Forestry University(BLRC2023B08).

摘　　要：The most important process before leaf senescence is nutrient resorption,which reduces nutrient loss and maximizes plant fitness during the subsequent growth period.However,plants must retain certain levels of nitrogen(N)in their leaves to maintain carbon assimilation during hardening.The objective of this study was to investigate the tradeoffs in N investment between leaf N resorption and N for photosynthesis in seedlings with increased soil fertility during the hardening period.A field experiment was conducted to determine if and how soil fertility treatments(17,34,or 68 mg N seedling−1)affected N resorption and allocation to the photosynthetic apparatus in Quercus mongolica leaves during the hardening period.Seedlings were sampled at T1(after terminal bud formation),T2(between terminal bud formation and end of the growing period),and T3(at the end of the growing period).Results showed that photosynthetic N content continued to rise in T2,while N resorption started from non-photosynthetic N.Leaf N allocation to the photosynthetic apparatus increased as soil fertility increased,delaying N resorption.Additionally,soil fertility significantly affected N partitioning among different photosynthetic components,maintaining or increasing photosynthetic traits during senescence.This study demonstrates a tradeoff in N investment between resorption and photosynthesis to maintain photosynthetic assimilation capacity during the hardening period,and that soil fertility impacts this balance.Q.mongolica leaves primarily resorbed N from the non-photosynthetic apparatus and invested it in the photosynthetic apparatus,whereas different photosynthetic N component allocations effectively improved this pattern.

关 键 词：Nitrogen resorption Nitrogen allocation Photosynthetic components Quercus mongolica 

分 类 号：S792.186[农业科学—林木遗传育种]