古尔班通古特沙漠某些短命植物叶片N、P化学计量特征的季节变化

短命植物是荒漠生态系统的重要组成部分。为了解短命植物叶片N、P化学计量特征随生长季变化的特点,选择古尔班通古特沙漠6种优势短命植物(3种一年生短命植物,3种多年生类短命植物)为研究对象,对比了2种生活型短命植物叶片N、P化学计量特征随生长季变化特点。结果表明,3种一年生短命植物尖喙牻牛儿苗(Erodium oxyrrhynchum)、小花荆芥(Nepeta micrantha)以及条叶庭芥(Alyssum linifolium)N含量平均值(±标准差)分别为(11.23±7.16)、(14.11±6.38)和(10.85±6.14)mg·g–1;P含量平均值分别为(2.82±0.73)、(3.12±1.24)和(3.43±0.55)mg·g–1;3种多年生类短命植物独尾草(Eremurus chinensis)、雅葱(Scorzonera pusilla)和簇花芹(Soranthus meyeri)N含量的平均值分别为(19.97±5.94)(15.08±4.01)和(17.94±9.03)mg·g–1;P含量平均值分别为(3.55±0.83)、(2.73±1.11)和(5.03±0.65)mg·g–1。由此可见,短命植物在生长过程中叶片N-P化学计量特征存在一定差异。各物种N、P含量在生长初期都大于其它生长季节,在生长旺季随叶片生物量增加,N、P含量呈下降趋势;而在生长末季N、P含量又有所回升。相关性分析表明,不同生活型短命植物元素间的关系存在差异,但同一生活型短命植物元素间的关系并无显著差异,体现了种内一致性。

Seasonal Variation of N and P Stoichiometric Characteristics in Leaves of Certain Ephemeral Plants in the Gurbantunggut Desert,China

Ephemeral plants are an important part of desert ecosystems. To understand the stoichiometric characteristics of leaf N and P in growth season variation, we compared plant leaf N and P with seasonal variation among 6 main species of ephemeral plants in the Gurbantunggut Desert in China, including 3 species of annual ephemeral plants and 3 of perennial ephemeral plants: Erodium oxyrrhynchum, Nepeta micrantha, Alyssum linifolium, Eremurus chinensis, Scorzonera pusilla, and Soranthus meyeri. The mean N content for the 3 annual ephemeral species was (11.23±7.16), (14.11±6.38) and (10.85±6.14) mg·g^-1 and mean P content was (2.82±0.73), (3.12±1.24) and (3.43±0.55) mg·g^-1. The mean N content for the 3 perennial ephemeral species was (19.97±5.94), (15.08±4.01) and (17.94±9.03) mg·g^-1 and mean P content was (3.55±0.83), (2.73±1.11) and (5.03±0.65) mg·g^-1. The stoichiometric characteristics of leaf N-P differed during the growth of ephemeral plants. The content of N and P in each species was higher in the early growth stage than during other growing seasons. The content of N and P decreased with increasing leaf biomass in the growing season but increased in the late growth season. The relation among the elements at different life stages differed, with no significant difference in the relation between the elements of the same life stage, so it embodies the consistency of inter species.