Ye Jinkun, Ji Yuhui, Wang Jinfeng, Ma Xiaodong, Gao Jie
Key Laboratory for the Conservation and Regulation Biology of Species in Special Environments, College of Life Science, Xinjiang Normal University, Urumqi, China.
Key Laboratory of Earth Surface Processes of Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, China.
Front Plant Sci. 2024 Aug 7;15:1430027. doi: 10.3389/fpls.2024.1430027. eCollection 2024.
Specific leaf area (SLA) and leaf dry matter content (LDMC) are key leaf functional traits often used to reflect plant resource utilization strategies and predict plant responses to environmental changes. In general, grassland plants at different elevations exhibit varying survival strategies. However, it remains unclear how grassland plants adapt to changes in elevation and their driving factors. To address this issue, we utilized SLA and LDMC data of grassland plants from 223 study sites at different elevations in China, along with climate and soil data, to investigate variations in resource utilization strategies of grassland plants along different elevational gradients and their dominant influencing factors employing linear mixed-effects models, variance partitioning method, piecewise Structural Equation Modeling, etc. The results show that with increasing elevation, SLA significantly decreases, and LDMC significantly increases ( < 0.001). This indicates different resource utilization strategies of grassland plants across elevation gradients, transitioning from a "faster investment-return" at lower elevations to a "slower investment-return" at higher elevations. Across different elevation gradients, climatic factors are the main factors affecting grassland plant resource utilization strategies, with soil nutrient factors also playing a non-negligible coordinating role. Among these, mean annual precipitation and hottest month mean temperature are key climatic factors influencing SLA of grassland plants, explaining 28.94% and 23.88% of SLA variation, respectively. The key factors affecting LDMC of grassland plants are mainly hottest month mean temperature and soil phosphorus content, with relative importance of 24.24% and 20.27%, respectively. Additionally, the direct effect of elevation on grassland plant resource utilization strategies is greater than its indirect effect (through influencing climatic and soil nutrient factors). These findings emphasize the substantive impact of elevation on grassland plant resource utilization strategies and have important ecological value for grassland management and protection under global change.
比叶面积（SLA）和叶片干物质含量（LDMC）是关键的叶片功能性状，常被用于反映植物资源利用策略并预测植物对环境变化的响应。一般而言，不同海拔的草原植物表现出不同的生存策略。然而，草原植物如何适应海拔变化及其驱动因素仍不清楚。为解决这一问题，我们利用了中国不同海拔223个研究地点的草原植物的SLA和LDMC数据，以及气候和土壤数据，采用线性混合效应模型、方差分解法、分段结构方程模型等方法，研究草原植物沿不同海拔梯度的资源利用策略变化及其主要影响因素。结果表明，随着海拔升高，SLA显著降低，LDMC显著增加（<0.001）。这表明草原植物在不同海拔梯度上有不同的资源利用策略，从低海拔的“快速投资回报”转变为高海拔的“缓慢投资回报”。在不同海拔梯度上，气候因素是影响草原植物资源利用策略的主要因素，土壤养分因素也起着不可忽视的协同作用。其中，年平均降水量和最热月平均温度是影响草原植物SLA的关键气候因素，分别解释了SLA变异的28.94%和23.88%。影响草原植物LDMC的关键因素主要是最热月平均温度和土壤磷含量，相对重要性分别为24.24%和20.27%。此外，海拔对草原植物资源利用策略的直接影响大于其间接影响（通过影响气候和土壤养分因素）。这些发现强调了海拔对草原植物资源利用策略的实质性影响，对全球变化下的草原管理和保护具有重要的生态价值。
