高寒草甸植物叶片碳含量及其可塑性与系统发育的关系

Phylogenetic relationships of leaf carbon content and plasticity in alpine meadow plants

植物的系统发育极大地影响着植物的功能性状,高寒草甸草本植物叶片碳含量、性状及其可塑性是否受植物遗传背景的影响目前仍不明确。为此,本研究测定了土壤氮、磷异质条件下高寒草甸生态系统12种优势植物叶片碳含量、比叶面积及其可塑性,并分析其在种、科水平上的差异以及系统发育保守性。结果显示,在不同土壤氮条件下,植物叶片碳含量和比叶面积在种、科水平差异显著(P<0.05)。不同土壤磷条件下,植物叶片碳含量在种、科水平无显著差异,但比叶面积差异显著(P<0.05)。叶片碳含量和比叶面积没有相关性,但两者的可塑性呈显著正相关,说明不同植物的这两个性状对土壤氮、磷的变化有相似的响应方式。叶片碳含量、比叶面积及其两者的可塑性均没有检测出显著的系统发育信号,说明相对于遗传背景,叶片碳含量、比叶面积主要受环境变化的影响。本研究有助于理解全球变化背景下高寒草甸碳循环过程,也可以为退化高寒草甸的恢复和管理提供科学依据。

Phylogeny greatly affects plant functional traits. It is still unclear whether leaf carbon content,leaf traits and their plasticity of alpine meadow plants are influenced by their genetic background. We measured foliar carbon content,specific leaf area and their plasticity of 12 dominant plants in alpine meadow ecosystems under soil nitrogen and phosphorus heterogeneous conditions and analyzed their differences at species and family levels and their phylogenetic conservatism. The results showed that,at species and family levels,foliar carbon contents and specific leaf area were significantly different（ P〈0.05） at different soil nitrogen conditions. The difference of carbon content was not significant under different soil phosphorus conditions,but the specific leaf area had significant difference（ P 〈 0. 05）. There was no correlation between foliar carbon content and specific leaf area,but their plasticity was positively correlated,indicating that the two traits of different species had similar response to variation of soil nitrogen and phosphorus.Meanwhile,no significant phylogenetic signal was detected in foliar carbon content,specific leaf area and their plasticity,suggesting that those traits and their plasticity were more affected by environmental changes than by their genetic background. This study is helpful to understand the process of carbon cycling in alpine meadow under the global change background,and would provide scientific basis for the restoration and management of degraded alpine meadow.