西双版纳热带季节雨林优势树种叶片干旱耐受和机械抗性的协同关系

Coordination Relationship Between Drought Tolerance and Mechanical Resistance of Leaves of Dominant Tree Species, in Xishuangbanna Tropical Seasonal Rainforest, Southwest China

摘要:

全球气候变化导致的区域性干旱对植物的生存构成了严峻挑战，植物抗旱性和机械抗性是其生长存活的关键影响因素。热带森林作为地球上生物多样性和生产力最高的陆地生态系统，但其优势树种叶片干旱耐受性与机械抗性之间的关系尚不清楚。本研究以西双版纳热带季节雨林优势树种为研究对象，通过测定叶片压力-容积曲线、叶片机械抗性(LMR)、单位叶面积干重(LMA)和干物质含量(LDMC)等关键形态、结构和水力性状指标，结合系统发育分析，探讨了叶片干旱耐受性和机械抗性之间的关系及其驱动机制。结果表明，热带季节雨林树种叶片的形态、水力性状和机械抗性具有较大的变异，且不受显著系统发育约束；叶片抗旱能力和机械抗性与LMA和LDMC均呈显著正相关；叶片干旱耐受能力和机械抗性间也呈显著正相关，且这一共变关系受到叶片结构投资的调控。这揭示了热带季节雨林优势树种叶片抗旱性和机械抗性间存在协同关系，为理解该地区植物生态适应策略、预测气候变化下森林群落动态提供了科学依据。

Abstract:

Regional droughts caused by global climate change pose a severe challenge to plant survival. Plant drought resistance and mechanical resistance are key factors determining their growth and survival. Tropical forests, as the terrestrial ecosystems with the highest biodiversity and productivity on Earth, however, the relationship between drought tolerance and mechanical resistance of their dominant tree species leaves remains unclear. This study took the dominant tree species in the tropical seasonal rainforest of Xishuangbanna as the research object. By measuring key morphological and hydraulic traits such as the pressure-volume curve of leaves, leaf mechanical resistance (LMR), leaf dry matter content (LDMC), and leaf mass per area (LMA), and combining phylogenetic analysis to explore evolutionary relationships, the relationship between leaf drought tolerance and mechanical resistance and its driving mechanism were further analyzed. The results showed that the morphological, hydraulic traits and mechanical resistance of leaves of tropical seasonal rainforest tree species varied greatly and were not significantly constrained by phylogeny; leaf drought resistance and mechanical resistance were significantly positively correlated with LMA and LDMC; leaf drought tolerance and mechanical resistance were also significantly positively correlated, and this co-variation relationship was regulated by leaf structural investment. This reveals a synergistic relationship between leaf drought resistance and mechanical resistance in dominant tree species of tropical seasonal rainforests, providing a scientific basis for understanding the ecological adaptation strategies of plants in this region and predicting the dynamics of forest communities under climate change.