小兴安岭不同生长型阔叶植物叶性状变异及权衡

Leaf trait variation and trade-offs among growth types of broadleaf plants in Xiao Hinggan Mountains

植物叶功能性状的变异模式以及相关关系一直是解析植物对气候变化响应机制的关键,然而不同生长型阔叶植物间叶片结构性状和光合生理性状变异及相关性的异同性尚不清晰。该研究以典型阔叶红松(Pinus koraiensis)林中的优势或常见的18种阔叶植物为研究对象,通过测量4个结构性状(叶面积(LA)、叶片厚度(LT)、叶干物质含量(LDMC)和比叶质量(LMA))和4个光合生理性状(叶绿素值(SPAD)、胞间CO_(2)浓度(C_(i))、气孔导度(G_(s))和净光合速率(P_(n))),分析了在不同生长型阔叶植物叶片结构性状和光合生理性状的变异及相关性。结果表明:不同生长型植物叶功能性状的变异范围为7.73%-74.54%,其中种间变异是LA和LT的主要变异来源,C_(i)、SPAD、LDMC以及LMA的变异主要由生长型驱动,G_(s)和Pn变异的主要来源是种内;不同生长型叶功能性状间存在显著差异,其中草本的LA、LT和C_(i)显著高于灌木和乔木,乔木的LMA、LDMC、SPAD、P_(n)和G_(s)显著高于灌木和草本;不同生长型之间P_(n)和LMA、LDMC之间具有显著的异速生长关系,且斜率大于1,而SPAD和LA、LT、LDMC、LMA,Ci与LT、LDMC、LMA之间则呈斜率小于1的异速生长关系;草本采取“快速投资-收益”型(获取型)策略,相对而言,乔木采取“缓慢投资-收益”型(保守型)策略,灌木采取介于乔木与草本之间的资源利用策略,这可能与不同生长型植物所处环境的光照条件有关。植物叶片结构性状和光合生理特征的变异及相互关系的研究对于揭示植物资源获取与分配策略具有重要意义。

Aims Patterns of leaf trait variation and correlation have long been a key aspect in unraveling plant responses to climate change.However,the specifics of how these patterns of leaf structural traits and photosynthetic physiological characteristics align and differ across growth types of broadleaf plants remain unclear.Methods This study focused on 18 dominant or common broadleaf species in a mixed broadleaf-Korean pine(Pinus koraiensis)forest.We measured four structural traits(leaf area(LA),leaf thickness(LT),leaf dry matter content(LDMC)and leaf mass per area(LMA))and four photosynthetic physiological traits(leaf chlorophyll value(SPAD),intercellular CO_(2) concentration(C_(i)),stomatal conductance(G_(s))and net photosynthetic rate(P_(n))).We analyzed the variation and correlations between structural and physiological traits across different growth types of broadleaf plants.Important findings Leaf functional traits displayed variation ranges spanning from 7.73%to 74.54%.Interspecific differences accounted for the majority of variability for LA and LT,while growth type primarily drove variation in C_(i),SPAD,LDMC,and LMA.G_(s) and P_(n) variation originate mainly from intraspecific differences.There were significant differences among growth types for all leaf traits.Specifically,herbs showed significantly higher LA,LT,and C_(i) compared to shrubs and trees,trees exhibited significantly elevated LMA,LDMC,SPAD,Pn,and Gs compared to shrubs and herbs.There were significant isometric relationships between P_(n) and LMA,LDMC among growth types,with slopes above 1.For SPAD versus LA,LT,LDMC,LMA,along with Ci versus LT,LDMC,LMA,slopes remained under 1,indicating allometric growth relationships.Herbs displayed a resource-acquisitive strategy,while trees adopted a relatively conservative strategy.Falling intermediate,shrubs struck a balance,possibly linked to the light levels across their habitats.Investigating trade-off and connections between leaf structure and photosynthetic physiology proves critical for understanding resource acquisition and allocation mechanism in plants.