青藏高原星状雪兔子叶性状对海拔梯度的响应

Responses of leaf traits of Saussurea stella to an el⁃ evational gradient in Qinghai-Tibet Plateau

摘要:

【目的】探究青藏高原星状雪兔子(Saussurea stella)叶性状对高原胁迫环境的适应策略。 【方法】选取 5 个不同的海拔梯度(3 300、3 680、4 000、4 240、4 510 m)采集星状雪兔子和土壤样品，分析其叶面积、比叶面积、叶干重、叶干物质含量等叶指标及土壤全氮含量、pH、含水量等土壤理化性质指标。【结果】(1)星状雪兔子叶干重、叶干物质含量、叶面积均与海拔呈负相关关系(P＜0. 001)，而比叶面积、气孔密度和叶数量均与海拔呈正相关关系(P＜0. 01)；(2)全氮、全磷含量、pH 值、含水量等因子在不同海拔梯度上存在显著性差异(P＜0. 01)。其中，海拔和全氮含量是影响植物叶性状的主要控制因子。【结论】星状雪兔子以增大比叶面积、气孔密度和叶数量的方式来适应高原胁迫环境。

Abstract:

【Objective】 Leaf is a vegetative organ for photosynthesis and has a large contact area with the exter‐ nal environment，which can be used to explore the adaptation strategies of leaf traits to plateau stress environment. 【Method】Saussurea stella on the Qinghai‐Tibet Plateau was selected as the research object of this topic. Plant and soil samples were collected across five elevation gradients (3 300，3 680，4 000，4 240，4 510 m). Leaf indicators，such as leaf area，specific leaf area，leaf dry weight，and leaf dry matter content of the plant as well the soil physical and chemical properties，such as soil total nitrogen，pH，and soil moisture content were analyzed. Furthermore，the adapta‐ tion strategies of leaf traits to plateau stress environment were explored.【Result】(1) Our results showed that leaf dry weight，leaf dry matter content and leaf area were negatively correlated with elevation (P＜0. 001)，while specific leaf area，stomatal density and number of leaves were positively correlated with elevation (P＜0. 01)；(2) There were significant differences in factors，such as total nitrogen，total phosphorus，pH，and soil moisture content on differ‐ ent elevation gradients (P＜0. 01). Among them，elevation and total nitrogen were the main controlling factors affect‐ ing plant leaf traits.【Conclusion】 The results suggest that Saussurea stella adapts to the stressful environment of the plateau by increasing the specific leaf area，stomatal density and number of leaves.