Desert ecosystem has unique drought-enduring plants and stoichiometric characteristics. We collected leaf samples of 67 plant species from 63 desert sites in Xinjiang, and explored foliar carbon (C), nitrogen (N) and phosphorus (P) stoichiometry and the relationship between leaf nutrient stoichiometry and climatic factors. The results showed that the average content of leaf C, N and P in these plants were 394, 18.4 and 1.14 mg·g-1, respectively. The mean values of C:N, C:P and N:P were 28, 419 and 18, respectively. In general, shrubs had higher leaf N content than trees and herbs, while leaf P content was lower (higher) in shrubs than in herbaceous plants (trees). Plants with C3 photosynthesis pathway had higher leaf C, N, C:P and N:P than those with C4 pathway. With increasing mean annual precipitation, leaf C first decreased and then increased, while both leaf N and P showed the opposite trend. Leaf C:N and C:P first decreased and then increased, while leaf N:P changed insignificantly. With increasing mean annual temperature, leaf C first decreased and then increased, and leaf N and P decreased, while leaf C:P and N:P increased. Leaf C:N did not change significantly with mean annual temperature. Mean annual precipitation generally showed stronger control on the variation of leaf nutrient stoichiometry than MAT and plant functional types. These results could help predict responses of the biogeochemical cycling of C, N and P to the global climate changes and provide reference and basic data for biogeochemical modeling in the arid regions.
荒漠生态系统具有独特的耐旱植物种类和植物化学计量特征.本研究通过系统采集全疆63个荒漠地点的67种植物,探索荒漠植物叶碳、氮、磷(C、N、P)的计量特征及其与气候因子的关系.结果表明: 荒漠植物叶C、N和P的平均含量分别为394、18.4和1.14 mg·g-1,C∶N、C∶P和N∶P平均值分别为28、419和18.灌木的N含量高于乔木和草本,灌木P含量比草本(乔木)低(高);C3植物叶的C、N、C∶P、N∶P高于C4植物.随年均降水量增加,叶C有先降低后升高的趋势,叶N、P先升高、后降低,叶C∶N、C∶P与叶N、P变化趋势相反,N∶P变化不显著;随年均温升高,叶C先降低后升高,叶N、P降低,C∶N变化不显著,C∶P、N∶P升高.年均降水量对叶片化学计量特征的影响大于年均温度和植物类型.本研究结果将有助于预测全球气候变化背景下的C、N、P元素循环规律的变化,并为干旱区生物地球化学建模提供参考和基础数据.
Keywords: C3 plant; C4 plant; carbon; climatic factor; desert plant; ecological stoichiometry; nitrogen; phosphorus; plant life form.