叶片性状-环境关系对于预测气候变化对植物的影响至关重要。该研究以青藏高原东缘常见阔叶木本植物为研究对象, 从47个样点采集了332个物种共666个种群的叶片, 测量了15个叶片性状, 调查了该区域木本植物叶片性状的变异程度, 并从种内和种间水平探讨了叶片性状对环境的响应及适应策略。结果表明, 反眏叶片大小的性状均具有较高的变异, 其中, 叶片面积是变异程度最大的性状。除气孔密度外, 大多数叶片性状与海拔显著相关。气候是叶片性状变异的重要驱动因素, 3.3%-29.5%的叶片性状变异由气候因子组合解释。其中, 气温对叶片性状变异解释度最高, 日照时间能解释大部分叶片性状的变异, 而降水量对叶片性状变异的解释度相对较小。与环境(海拔和气候因子)显著相关的叶片性状在种内明显少于种间水平, 可能是植物性状之间的协同变化与权衡使种内性状变异比较小, 从而减弱了种内叶片性状与环境因子的相关性。研究结果总体表明,叶片性状与木本植物对环境的适应策略密切相关, 植物通过选择小而厚的叶片和较短的叶柄以适应高海拔的 环境。

Aims Leaf trait-environment relationships are critical for predicting the effects of climate change on plants. Our objective was to reveal the response of leaf traits of common broad-leaved woody plants to environmental factors on the eastern Qinghai-Xizang Plateau. Methods We measured 15 leaf traits of 332 species from 666 populations collected at 47 sites on the eastern Qinghai-Xizang Plateau. We investigated the extent of leaf trait variation in this area, and explored the response and adaptation strategies of leaf traits to environment at intra- and inter-species levels. Important findings Traits related to leaf size exhibited relatively high variation, and the leaf area was the most variant trait. Most leaf traits were significantly associated with elevation, except stomatal density. Climatic factors were important drivers of leaf trait variation because they explained 3.3%-29.5% of leaf trait variation. Meantime, temperature had the highest interpretation degree of leaf trait variation, and sunshine hours could explain the variation of most leaf traits. However, the interpretation degree of precipitation was relatively weak. In addition, the significant relationships between leaf traits and environmental (altitude and climatic) factors at intra-species level were far less than at inter-species levels. The reason for the result may be the coordinated variation and trade-off between plant traits, which make the variation of intra-species traits relatively small, and thus weaken the correlation between intra-plant leaf traits and environmental factors. Overall, leaf traits were closely related to woody plant adaptation strategies to the environment, and small, thick leaves and short petioles were selected for high-altitude plants to adapt to harsh environments such as strong winds and low temperature.