【作者】 王磊；

【导师】 夏志超；

【作者基本信息】 安徽农业大学 ， 森林培育， 2025， 硕士

【摘要】 磷素作为亚热带生态系统植物生产力的关键限制性养分,其叶片分配策略与利用效率研究对解析植物养分适应机制具有重要意义。叶片磷组分,包括无机磷(Pi)、代谢磷(PM;低分子量代谢物,如Ru BP、NADP、ATP、ADP,也包括储存化合物如植酸)、核酸磷(PN;RNA和DNA)、脂质磷(PL;磷脂,细胞膜的主要成分)及残余磷(PR;磷酸化蛋白和含有磷的未知化合物)通过参与光合磷酸化、核酸合成等关键生理过程,反映植物对磷资源的配置。尽管已有研究揭示了植物通过调整磷组分分配提升光合磷利用效率(Photosynthetic phosphorus use efficiency,PPUE)机制,但菌根共生关系与叶片经济学谱(Leaf economics spectrum,LES)对叶片磷分配策略的协同调控作用尚不清楚。本研究以亚热带典型人工林32种木本植物为研究对象,基于菌根共生类型(丛枝菌根AM树种与外生菌根EM树种)的系统划分,整合叶片经济学谱的关键性状(比叶重、光合速率等)与磷组分定量分析,重点探究:(1)不同菌根类型树种叶片磷组分分配模式的分异特征;(2)磷分配策略对PPUE的多维度调控路径;(3)菌根共生在叶片功能性状与磷组分关联中的调节效应。主要结果如下:(1)两种菌根类型树种叶片磷组分含量及分配模式存在显著差异。在磷组分的含量上,AM树种的Pi、PM、PN、PL的含量相较于EM树种高出19%～55%。在磷组分的相对分配方面,AM树种Pi的相对分配显著高于EM树种,而EM树种表现出更高的PM和PR分配比例。(2)两种菌根类型树种普遍通过减少Pi分配来提升光合磷利用效率(PPUE),但菌根类型驱动了差异化的再分配模式:AM树种优先投资于PN,而EM物种将更多磷分配给PM来优化PPUE。(3)本研究还揭示了菌根共生体对叶经济学谱(LES)与叶片磷分配之间的关联影响。AM树种具有资源获取特征,表现为低比叶重(LMA)、高光合速率,优先将磷分配给PN。相比之下,高LMA和厚叶的EM树种对PR的依赖更强。本研究系统解析了菌根共生类型调控植物磷分配策略与叶片功能性状互作关系的生态机制,从养分-功能性状协同进化的视角拓展了经典叶片经济谱理论的内涵。更多还原

【Abstract】 Phosphorus(P),as a key limiting nutrient for plant productivity in subtropical ecosystems, plays a crucial role in shaping leaf allocation strategies and utilization efficiency,which are essential for understanding plant nutrient adaptation mechanisms.Leaf P fractions,including orthophosphate P(Pi),metabolic P(PM;low-molecular-weight metabolites such as Ru BP,NADP,ATP,ADP,and storage compounds like phytic acid),nucleic acid P(PN;RNA and DNA),lipid P(PL;phospholipids,major components of cell membranes),and residual P(PR;phosphorylated proteins and unidentified P-containing compounds),reflect plant P allocation strategies through their involvement in critical physiological processes such as photophosphorylation and nucleic acid synthesis.Although existing studies have revealed mechanisms by which plants enhance photosynthetic phosphorus use efficiency(PPUE)through adjustments in P fraction allocation,the synergistic regulatory effects of mycorrhizal symbiosis and the leaf economics spectrum(LES)on leaf P allocation strategies remain unclear.This study investigated 32 woody species in a subtropical typical plantation forest,systematically categorizing them by mycorrhizal type(arbuscular mycorrhizal,AM,vs.ectomycorrhizal,EM).By integrating key LES traits(e.g.,leaf mass per area[LMA],photosynthetic rate)with quantitative analysis of leaf P fractions,we aimed to:(1)characterize divergence in leaf P allocation patterns between mycorrhizal types;(2)elucidate multidimensional regulatory pathways of P allocation strategies on PPUE;and(3)evaluate the mediating role of mycorrhizal symbiosis in linking leaf functional traits with P fractions.Key findings include:(1)Significant differences in leaf P fraction concentrations and allocation patterns between AM and EM trees.AM species exhibited 19%-55%higher absolute concentrations of Pi,PM,PN,and PL than EM species.In relative allocation,AM species allocated significantly more P to Pi,while EM species showed higher proportional investments in PM and PR.(2)Both types of mycorrhizal tree species generally enhance photosynthetic phosphorus use efficiency(PPUE)by reducing Pi allocation,but mycorrhizal types drive differentiated reallocation patterns:AM tree species prioritize investment in PN,while EM species allocate more phosphorus to PM to optimize PPUE.(3)Mycorrhizal symbiosis modulated LES-P allocation relationships.AM species,characterized by resource-acquisitive traits(low LMA,high photosynthetic rates),preferentially allocated P to PN.In contrast,EM species with conservative traits(high LMA,thicker leaves)exhibited stronger reliance on PR.This study systematically deciphers the ecological mechanisms by which mycorrhizal types regulate plant P allocation strategies and their interactions with leaf functional traits.It expands the theoretical framework of the classical LES from the perspective of nutrient-functional trait co-evolution.更多还原