祁连圆柏光合色素与非结构性碳水化合物含量对海拔变化的响应

以祁连山林线附近(海拔2 860～3 323m)祁连圆柏(Sabina przewalskii)为研究对象,于7月下旬对不同海拔祁连圆柏成年树(胸径20cm左右)及幼树(胸径10cm左右)当年生叶的光合色素(叶绿素和类胡萝卜素)和非结构性碳水化合物(NSC,包括可溶性糖和淀粉)含量变化进行研究。结果显示:(1)祁连圆柏幼树叶片总叶绿素含量呈升高-降低-升高的趋势,成年树呈先降低再升高的趋势,但二者最低值均出现在海拔3 120m;类胡萝卜素含量成年树最高值出现在海拔3 320m处,幼树的最高值则出现在低海拔2 980m处。(2)NSC含量随海拔升高呈升高-降低-升高的变化趋势,最低值出现在海拔3 120m,而且幼树的NSC平均含量在各海拔显著高于成年树。研究说明,祁连圆柏随着海拔升高光合能力可能并未降低,而且在高海拔地的NSC供应充足,这暗示在全球气候变化背景下祁连圆柏林线具有沿海拔上升的潜力。

Variations of Chloroplast Pigments and Non-structural Carbohydrates of Sabina przewalskii along Altitude in Qilian Mountains Timberline

In this study,the contents of photosynthetic pigments (chlorophyll and carotenoid) and non-structural carbohydrates (NSC;soluble sugars and starches) of the current-year leaves were investigated in young and adult trees of Sabina przewalskii along altitude nearby the timberline of Qilian Mountains.The results demonstrated that:(1)Total chlorophyll contents firstly increased,and then decreased,finally increased again in young trees,while it firstly decreased,and then increased in adult trees,but the lowest values occurred at 3 120 m in both trees.However,the highest value of carotenoid appeared at 2 980 m in young trees,whereas it was at 3 320 m in adult trees.(2)NSC content showed the similar trend to total chlorophyll contents,moreover,the lowest values also occurred at 3 120 m in both trees;but NSC contents of the young trees were higher than that of the adult ones at the corresponding altitude.These suggested that the photosynthetic capacity of S.przewalskii might not decrease with the increasing altitude,and NSC supplied adequately at the higher altitude,which also indicated that the timberline of Qilian Mountains would have the potential to be pushed up to the higher altitude with the global climate changes.