塔里木盆地北缘荒漠典型植物叶片化学计量特征及其与土壤环境因子的关系

Leaf stoichiometric characteristics of typical desert plants and their relationships to soil environmental factors in the northern margin of the Tarin Basin

以塔里木盆地北缘胡杨、多枝柽柳、骆驼刺、花花柴和芦苇5种荒漠典型植物为研究对象,分析植物叶片碳(C)、氮(N)、磷(P)化学计量特征,结合冗余分析探讨叶片元素化学计量特征及其与土壤环境因子的关系。结果表明,5种植物叶片C、N、P含量平均值分别为451.65、16.98和1.08 mg·g^(-1),均低于全球植物平均水平,植物生长倾向于受N和P共同限制。植物体内元素含量及其计量比在物种之间存在较大的差异,胡杨C含量较低,骆驼刺具有相对较高的N含量与N∶P值,芦苇和花花柴P含量最高。Pearson相关分析表明,叶片N与P含量之间呈极显著正相关,C含量与N、P含量的相关性则不显著。冗余分析表明,土壤含水量、盐度和pH值能很好地解释叶片化学计量特征的差异性,其中土壤含水量是叶片C、N、P含量及其化学计量比变化的主要驱动因子,土壤全N含量、全P含量、总溶解固体和有机C含量对叶片化学计量特征的影响相对较小。

Studies on the relationship between desert plant leaf stoichiometry and soil environmental factors are of great importance to clarify the mechanism of adaptation and feedback to the soil environment in the process of plant growth. The leaf stoichiometric characteristics of five desert plants （Populus euphratica, Tamarix ramosissma, Alhagi sparsifolia, Karelinia caspia and Phragmites australis） were analyzed and their relationships to soil environmental factors were studied by redundancy analysis （RDA）. The results showed that the average contents of carbon （C）, nitrogen （N） and phosphorus （P） were 451.65, 16.98 and 1.08 mg·g-1 respectively, each lower than the global average level of plants, and the plant growth was more likely to be limited by both N and P. The leaf stoichiometric characteristics differed significantly among the five species, in which P. euphratica had the lowest C content, A. sparsifolia had the highest N content and N∶P ratio, and Ph. australis and K. caspia had the highest P content. Correlation analysis showed that there was extremely significant positive correlation between N content and P content, while there was no significant correlation between C content and N, P contents. According to RDA results, soil moisture content, salinity and pH value served as a good explanation for the difference of leaf stoichiometric characteristics, among which soil moisture was the major factor affecting leaf stoichiometric characteristics, while the effects of soil total N, total P, total dissolved solids, and organic C contents on leaf stoichiometric characteristics were relatively insignificant.