沙冬青叶片化学计量特征及其驱动因素

Characteristics of leaf stoichiometry and the driving factors of Ammopiptanthus mongolicus,China

叶片化学计量特征能反映植物对周围环境的适应性,研究两者之间的关系有助于探究植物对典型荒漠环境的适应策略。本研究以国家二级重点保护植物沙冬青为研究对象,设置26个典型样地,测定了叶片碳(C)、氮(N)、磷(P)含量和水分利用效率(WUE),分析叶片化学计量特征与WUE之间的协同关系,同时量化土壤、气候因子和水分利用效率对叶片化学计量特征变化规律的解释量。结果表明:沙冬青叶片C、N和P含量均值分别为(583.99±27.93)、(24.31±2.09)、(1.83±0.06)mg·g^(-1);变异系数分别为4.8%、8.6%、3.2%,均属弱变异性,表明沙冬青叶片C、N和P含量趋向于某一稳定值,沙冬青叶片N:P平均值为13.3,说明沙冬青生长主要受N元素限制。WUE与沙冬青叶片C含量不相关,与叶片N、P含量和N:P呈显著正相关关系,与C:N和C:P呈显著负相关关系,这说明WUE与叶片养分含量存在明显的线性协同变化趋势。影响叶片C含量和C:P的主要是气候因子,影响叶片N含量和N:P的主要是土壤因子,影响叶片P含量和C:N的主要是水分利用效率,这表明不同化学计量特征的驱动因子各不相同。本研究结果有助于评估荒漠植物沙冬青栖息地的适宜性,可为沙冬青的科学保护和管理提供理论依据。

The stoichiometric characteristics of leaves can reflect environmental adaptation of plants,and thus the study of the relationship between them is helpful for exploring plant adaptation strategies.In this study,taking the national second-level key protection species,Ammopiptanthus mongolicus,as the research object,we set up 26 plots to collect samples,and measured the content of carbon(C),nitrogen(N),phosphorus(P)and water use efficiency(WUE)of leaves.We analyzed the relationship between leaf stoichiometric characteristics and WUE,and quantified the contributions of soil,climate,and water use efficiency to the variations of leaf stoichiometry.The results showed that C,N,and P contents in the leaves were(583.99±27.93),(24.31±2.09),and(1.83±0.06)mg·g^(-1),respectively.The coefficients of variation were 4.8%,8.6%,and 3.2%,respectively,all belonging to weak variability,indicating that foliar contents of C,N and P tended to a certain stable value.The average value of N:P was 13.3,indicating that the growth of A.mongolicus was mainly limited by N.WUE was not correlated with leaf C content,but was significantly positively correlated with leaf N and P contents and N:P,and significantly negatively correlated with C:N and C:P,indicating that there was a linear synergistic trend between WUE and leaf nutrient content.The main factors influencing leaf C content and C:P were climatic factors,the leaf N content and N:P were mainly affected by soil factors,and the water use efficiency mainly affected leaf P content and C:N,indicating that the driving factors of different stoichiometric characteristics were different.The results could help evaluate the habitat adaptation of desert plants,which would provide a theoretical basis for the conservation and management of A.mongolicus.