Exploring plant adaptation strategies to phosphorus limitation induced by nitrogen addition:foliar phosphorus allocation and root functional traits analysis in two dominant subalpine tree species  

探究植物对氮添加诱导的磷缺乏的适应策略:两种亚高山优势树种叶片磷分配及根系功能性状分析

作　　者：Yan Su Yongfeng Tang Yi Hu Meiyu Liu Xuyang Lu Baoli Duan 

机构地区：[1]Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041,China [2]Sichuan Ecological Environment Construction Engineering Supervision Co.,Ltd.,Chengdu 610084,China

出　　处：《Journal of Plant Ecology》2024年第4期154-166,共13页植物生态学报（英文版）

基　　金：supported by Open Foundation of the Key Laboratory of Natural Resource Coupling Process and Effects(2023KFKTA005,2023KFKTB012);by the Science and Technology Research Program of Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(IMHE-ZDRW-06).

摘　　要：Plants adapt to the limitation of soil phosphorus(P)induced by nitrogen(N)deposition through a complex interaction of various root and leaf functional traits.In this study,a pot experiment was conducted to explore the effects of different levels of N addition(control,low N[LN]:25 kg N ha^(-1) yr^(-1),high N[HN]:50 kg N ha^(-1) yr^(-1))on tree growth,leaf nutrient content,foliar P fractions and root characteristics of two dominant tree species,the pioneer species Salix rehderiana Schneid and the climax species Abies fabri(Mast.)Craib,in a subalpine forest in southwestern China.The results demonstrated that LN addition had a minimal impact on leaf N and P contents.Conversely,HN addition significantly decreased the leaf P content in both species.Salix rehderiana exhibited more pronounced increases in specific root length and specific root area under P deficiency triggered by HN addition when compared with A.fabri.In contrast,A.fabri showed weaker morphological responses to N addition but had a higher proportion of foliar P to metabolic P,as well as higher root exudates rate and root phosphatase activity in response to HN addition.Abies fabri employs a synergistic approach by allocating a greater amount of leaf P to metabolite P and extracting P from the soil through P-mobilizing exudates and root phosphatase activity,while S.rehderiana exhibits higher flexibility in modifying its root morphology in response to P limitation induced by HN addition.This study provides insights into subalpine tree species adaptation to N-induced P limitation,emphasizing its significance for guiding forest management and conservation in the context of global climate change.植物通过各种根系和叶片功能性状的复杂相互作用来适应氮(N)沉降诱导的土壤磷(P)限制。本文通过控制实验研究不同水平N添加对西南亚高山森林两种主要树种——先锋树种川滇柳(Salix rehderiana Schneid)和顶级群落树种峨眉冷杉(Abies fabri(Mast.)Craib)的生长、叶片养分含量、叶片P组分以及根系功能性状的影响。不同N水平处理包括对照、低N(25 kg N ha^(-1) yr^(-1))和高N(50 kg N ha^(-1) yr^(-1))。实验结果表明,低N添加对这两种树种的叶片N和P含量无显著影响,而高N添加下两种树种的叶片P含量均显著下降。与峨眉冷杉相比,川滇柳在面临由高N添加引发的P缺乏时,其比根长(SRL)和比根面积(SRA)的增加更为显著。相反,峨眉冷杉在N添加下根系形态变化不明显,但在高N添加下,其叶片P向代谢P的分配比例较高,并且其根系分泌碳含量与根系磷酸酶的活性显著升高。这些发现表明,两种树种在适应高N添加引起的P缺乏时采取了不同的适应策略。峨眉冷杉通过地上-地下协同作用,优化了叶片P向代谢P的分配,同时借助磷活化分泌物和根系磷酸酶的活性从土壤中获取P,而川滇柳则通过调整其根系形态来应对高N添加导致的P缺乏。本研究深化了对亚高山树种如何适应N添加诱导的P缺乏现象的认知,同时也为科学指导森林管理和保护工作提供了重要依据。

关 键 词：N deposition root functional traits root morphology root exudation P-scavenging strategy 

分 类 号：Q948.1[生物学—植物学]