亚高山川西云杉林叶片养分重吸收与经济性状的关系及其环境驱动因素

Relationship between leaf nutrient resorption and economic traits and its environmental driving factors in subalpine Picea likiangensis var.balfouriana forests

阐明叶养分重吸收与叶片经济性状间的关系对于理解植物的养分吸收与利用策略至关重要;然而,关于叶养分重吸收是否以及如何与叶片经济性状相协调目前仍知之甚少,特别是在由外生菌根(ECM)主导的高寒针叶林中.以青藏高原东缘广泛分布且与ECM高度共生的川西云杉(Picea likiangensis var.balfouriana)为对象,探究17个种群叶氮(N)、磷(P)重吸收效率与叶片形态(厚度、组织密度、比叶面积)和化学性状(N、P浓度)间的协变关系及其环境驱动因素.结果表明:(1)N、P重吸收效率与叶片经济性状沿“叶经济谱”共变,并与叶片厚度、组织密度存在显著的正相关关系,与比叶面积、叶片N和P含量呈显著的负相关关系.这表明在叶片养分吸收与利用中,养分重吸收与叶保守型性状(厚度、组织密度)存在协同关系,而与获取型性状(比叶面积、N和P含量)呈权衡关系;(2)温度是影响N、P重吸收效率和叶片经济性状变化的主导因素,且随着温度降低,N、P重吸收效率和叶片厚度及组织密度均呈显著增加,而比叶面积和叶片N、P浓度则呈显著降低趋势.总体上,本研究表明温度驱动高寒针叶林叶养分重吸收与叶经济性状间的协调关系;上述研究成果有助于丰富和提升对高寒森林碳与养分经济协调性及其驱动机制的认知,同时对于理解和预测气候变化背景下高寒森林的适应性具有重要意义.(图4表2参37)

Elucidating the relationship between leaf nutrient resorption and economic traits is important for understanding plant nutrient uptake and utilization strategies.However,our knowledge of whether and how leaf nutrient resorption is coordinated with leaf economic traits,particularly in ectomycorrhizal(ECM)-dominated conifers in alpine forests,remains limited.Here,the relationships between leaf nutrient resorption and economic traits and their environmental drivers were investigated by measuring leaf nitrogen(N)and phosphorous(P)resorption efficiencies,leaf morphology(leaf thickness[LT],leaf tissue density[LTD],and specific leaf area[SLA]),chemical(N and P concentrations)traits,and environmental factors of 17 ECM spruce populations(Picea likiangensis var.balfouriana)in the eastern Tibetan Plateau of China.The results showed that:(1)N resorption efficiency(NRE)and P resorption efficiency(PRE)were significantly correlated with leaf traits,among which NRE and PRE were negatively correlated with SLA and leaf N and P concentrations and positively correlated with LT and LTD.This suggests that leaf nutrient resorption is a resource-conservative trait,which functions in tandem with leaf conservative traits(LT and LTD)and trade-off with leaf acquisitive traits(SLA,leaf N and P concentrations)in leaf nutrient uptake and utilization.(2)Temperature was the dominant factor affecting NRE,PRE,and leaf economic traits.With decreasing temperature,NRE,PRE,LT,and LTD tended to increase,whereas SLA and leaf N and P concentrations tended to decrease.Collectively,this study reveals that temperature played a critical role in driving the coordination between leaf nutrient resorption and leaf economic traits.This finding enriches the understanding of the coordination of carbon and nutrient economics and its driving mechanism in alpine forests and is significant for understanding and predicting the adaptability of alpine forests in the context of climate change.