Table_1_Response of Leaf Traits of Eastern Qinghai-Tibetan Broad-Leaved Woody Plants to Climatic Factors.DOCX

Plant ecologists have long been interested in quantifying how leaf traits vary with climate factors, but there is a paucity of knowledge on these relationships given a large number of the relevant leaf traits and climate factors to be considered. We examined the responses of 11 leaf traits (including leaf morphology, stomatal structure and chemical properties) to eight common climate factors for 340 eastern Qinghai-Tibetan woody species. We showed temperature as the strongest predictor of leaf size and shape, stomatal size and form, and leaf nitrogen and phosphorus concentrations, implying the important role of local heat quantity in determining the variation in the cell- or organ-level leaf morphology and leaf biochemical properties. The effects of moisture-related climate factors (including precipitation and humidity) on leaf growth were mainly through variability in leaf traits (e.g., specific leaf area and stomatal density) related to plant water-use physiological processes. In contrast, sunshine hours affected mainly cell- and organ-level leaf size and shape, with plants developing small/narrow leaves and stomata to decrease leaf damage and water loss under prolonged solar radiation. Moreover, two sets of significant leaf trait-climate relationships, i.e., the leaf/stomata size traits co-varying with temperature, and the water use-related leaf traits co-varying with precipitation, were obtained when analyzing multi-trait relationships, suggesting these traits as good indicators of climate gradients. Our findings contributed evidence to enhance understanding of the regional patterns in leaf trait variation and its environmental determinants.

植物生态学家长期以来一直致力于量化叶片性状随气候因子的变化规律，但由于需考量的相关叶片性状与气候因子数量众多，目前对二者间关联的认知仍较为匮乏。本研究针对青藏高原东部340种木本植物，分析了11项叶片性状（涵盖叶片形态、气孔结构与化学特性）对8种常见气候因子的响应规律。研究发现，温度是叶片大小与形态、气孔大小与构型以及叶片氮、磷浓度的最强预测因子，这表明局地热状况在决定细胞或器官水平的叶片形态与叶片生化特性变异中发挥着关键作用。与水分相关的气候因子（包括降水与湿度）对叶片生长的影响，主要通过与植物水分利用生理过程相关的叶片性状（如比叶面积（specific leaf area）、气孔密度）的变异来实现。与之相对，日照时长主要影响细胞与器官水平的叶片大小与形态：在长期太阳辐射下，植物会形成更小、更狭长的叶片与气孔，以降低叶片损伤与水分流失。此外，在分析多性状关联时，我们发现了两组显著的叶片性状-气候因子关联：即叶片/气孔大小性状随温度协同变化，以及水分利用相关叶片性状随降水协同变化，这表明这些性状可作为气候梯度的良好指示指标。本研究的发现为深化对叶片性状变异的区域格局及其环境驱动因子的认知提供了新的实证依据。