卧龙竹类非结构性碳水化合物与叶氮含量对海拔的响应

山地由于海拔变化导致的环境因子显著差异,成为研究植物环境适应性及其对全球气候变化响应的理想区域。以卧龙自然保护区内油竹子(Fargesia angustissima Yi)与华西箭竹(Fargesia nitida(Mitford)Keng f.ex Yi)为对象,沿海拔梯度研究了两种竹子在各自海拔分布区间内组织非结构性碳水化合物(NSC)含量、比叶面积(SLA)、以及基于单位叶面积和单位叶质量的叶氮含量(Narea,Nmass)。除油竹子叶NSC,Narea和华西箭竹Nmass随海拔升高不发生变化外,两种竹子其它调查因子对海拔的响应均是非线性的,反映了环境因子随海拔的非线性变化。所有调查因子对海拔的响应均表现出明显的种间差别,这一结果除了种间生理生态特性差别的原因外,可能意味着两竹种对温度的敏感性不同。高海拔种(华西箭竹)比(中)低海拔种(油竹子)对全球气候暖化可能更加敏感。

Responses of tissue non-structural carbohydrates and leaf nitrogen contents to altitude in two dwarf bamboos in Wolong

The strong altitudinal gradients leading to dramatic variations in environmental conditions in mountain regions provide unique and sometimes the best opportunities to study plant responses and adaptation to global climate change. We investigated tissue non-structural carbohydrates content (NSC), specific leaf area (SLA), mass-based (Nmass) and area-based (Narea) leaf nitrogen in two dwarf bamboos, Fargesia angustissima Yi and Fargesia nitida (Mitford) Keng f. ex Yi, growing along elevational gradients in Wolong Nature Reserve. Leaf NSC content and Narea in F. angustissima, and Nmass in F. nitida did not respond to altitude, whereas all other parameters studied changed non-linearly with increasing elevation for both bamboo species. This result may imply that the local-environmental conditions do not change linearly with altitude. The altitudinal responses of the parameters studied are species-specific. This result may reflect both the species-specific ecophysiology and the species-specific sensitivity to temperature. The high-altitude species (F. nitida) may be more sensitive to global warming than the low-altitude species (F. angustissima).