巴郎山大叶醉鱼草叶片非结构性碳水化合物和氮分配的海拔响应

为深入认识和探讨植物对环境变化的生理生态响应和适应，以分布在川西巴郎山的大叶醉鱼草(Buddleja davidii)为研究对象，沿海拔梯度对植物叶片中非结构性碳水化合物(NSC)、可溶性糖和淀粉含量，氮含量和氮分配比例(光合系统氮分配比例P_P、细胞壁氮分配比例P_CW和其他组分氮分配比例P_other)等参数进行对比分析，探讨其沿海拔的变化趋势，以及叶片NSC、可溶性糖和淀粉含量与氮分配间的相关关系。结果显示：大叶醉鱼草叶片NSC、可溶性糖、淀粉和单糖含量随海拔的升高而增加，而可溶性糖/淀粉比值未发生显著变化，表明高海拔较高的NSC含量的累积是由可溶性糖和淀粉含量共同决定的，而可溶性糖含量的增加主要由单糖含量的变化引起。叶片氮含量和P_P在海拔间差异不显著，但P_CW和P_other分别随海拔升高而降低和升高。此外，随海拔升高，叶片NSC/N比值随之增加，这主要归因于随海拔升高而增加的NSC含量而非海拔间差异不显著的氮含量。NSC含量和可溶性糖含量均与P_other显著正相关，说明叶片P_other和NSC含量的累积共同用于提高大叶醉鱼草在高海拔恶劣环境下的适应性。

Response of leaf non-structural carbohydrate and nitrogen allocations to an elevation gradient in Buddleja davidii along Balang Mountain, Sichuan Province

In order to better understand and explore the physiological and ecological response and adaptation of plants to environmental changes, Buddleja davidii distributed in the Balang Mountain in western Sichuan province was selected as the object. The contents of leaf non-structural carbohydrates (NSC), soluble sugar and starch, nitrogen concentration and nitrogen allocation fractions (fraction of leaf nitrogen allocated to photosynthetic apparatus P_P, cell wall P_CW and other components P_other) along an elevation gradient were compared to study their elevational patterns. Moreover, the correlations between the NSC, soluble sugar, starch and nitrogen allocations were analyzed. The results showed that the NSC, soluble sugar, starch and monosaccharides content of B. davidii leaves increased, while the soluble sugar/starch ratio did not change significantly along with elevation. These indicated that the accumulation of NSC at high elevation was determined by both soluble sugar content and starch content, while the increase in soluble sugar was mainly caused by monosaccharides content. Although leaf nitrogen concentration and P_P were not significantly different among elevations, P_CW and P_other decreased and increased along with elevation, respectively. Additionally, the NSC/N ratio of B. davidii leaves increased along with elevation, which was mainly caused by the increasing NSC content along the elevation rather than the insignificant nitrogen concentration among the different elevations. The contents of NSC and soluble sugar had significantly positive correlations with P_other, indicating that the accumulation of P_other and NSC content functioned together to improve the adaptability of the plants in the harsh environment at high elevation.