干旱区研究2012，Vol.29Issue(5)：784-790,7.
天然林中不同径级新疆野苹果的光合能力
Photosynthetic Capacity of Malus sieversii Trees in Natural Forest
摘要
Abstract
Photosynthesis is a basic eco-physiological process for the functioning of ecosystems. Malus sieversii （ Ledeb. ） Roem. is the most important dominant species in the wild fruit forest on the northern slope of the Tians-han Mountains in northwest China. M. sieversi population has been declining rapidly due to more and more inten-sive anthropogenic disturbances. Research on the photosynthetic characteristics of M. sieversii of different size clas-ses is critical to understand the functions of its dominated ecosystems and to take proper measures to conserve this endangered species. Net assimilation rate （A）, stomotal conductance （gs） and specific leaf area （SLA） of sun-fa-cing M. sieversii leaves at upper and lower parts of 64 adult trees were .measured in a natural wild fruit forest in Xinyuan County on the northern slope of the Tianshan Mountains in Xinjiang, northwest China. The results showed that there was a significant effect of stem diameter class on photosynthetic characteristics of M. sieversii. Both Aarea and Amass were increased with the increase of diameter class, whereas gs was incieased at first and then decreased, and the maximum values appeared at the main stem diameter of 25 - 35 cm at 0.5 m height. There was a signifi-cant effect of leaf position on photosynthetic characteristics. Amarea,Amass and gs of the leaves on the upper part of branches were significantly higher than those on the lower part. The results of regression analysis revealed that Aarea and gs were increased in a quadratic polynomial way with the increase of stem diameter, whereas Amass was in- creased in a linear relation. With the increase of diameter class, the change of SLA was not significant. There was a significant effect of leaf position on SLA. SLA of the leaves on the upper part of crown was significantly lower than that on lower part, and the differences of Amass between the leaves on the upper and lower parts was low. A area of the leaves on both upper and lower parts was increased with the increase of gs, but the regression equations were different. Aarea of upper leaves was increased in a power function with the increase of gs, whereas Aarea of lower leav-es was increased in a quadratic polynomial way with the increase of gs.关键词
新疆野苹果（Malus/sieversii）/净光合速率/比叶面积/气孔导度/野果林/新源县/新疆Key words
Malus sieversii/net photosynthetic rate/specific leaf area/stomotal conductance/wild fruit forest/Xinyuan County/Xinjiang分类
农业科技引用本文复制引用
毛培利,臧润国,白志强,许正,郭仲军,刘端..天然林中不同径级新疆野苹果的光合能力[J].干旱区研究,2012,29(5):784-790,7.基金项目
公益性行业科研专项项目 （）
