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理解影响植物分布的式样及过程是生态学研究的中心内容之一,但对许多物种而言,限制其分布的原因还不清楚。为了认识高山栎分布与生理生态特性的关系,我们在不同海拔的4个观测点研究了帽斗栎的光合气体交换、叶氮含量、叶绿素含量和比叶重。由于高的水气压亏缺和气温,帽斗栎的光合作用和蒸腾作用在午间表现出明显的降低现象。帽斗栎的饱和光合速率、水分利用效率、最大羧化速率、最大电子传递速率和氮利用效率在海拔中部比低海拔或高海拔处的为高。不同海拔的叶氮含量在5月份有差异,8月份则没有明显不同。叶片厚度随海拔增加,但叶绿素含量及光合最适温度随海拔升高而降低。帽斗栎光合作用的海拔变化与叶片的生化效率和氮含量有关,而与比叶重无关。研究结果说明,温度的海拔变化对高山栎的光合作用和叶性状有明显影响,最适宜帽斗栎光合碳获取及生长的海拔范围是3180～3610m。
Understanding the patterns and processes that affect the distribution of plants is one of the central topics in ecology, but the reasons for limiting their distribution are not clear for many species. In order to understand the relationship between the distribution of alpine oaks and their ecophysiological characteristics, we studied the photosynthetic gas exchange, leaf nitrogen content, chlorophyll content and specific leaf weight at 4 observation sites at different altitudes. Due to the high water pressure deficit and temperature, the photosynthesis and transpiration of Pinctada oblata showed a marked decrease during midday. The photosynthetic rate, water use efficiency, maximal carboxylation rate, maximum electron transfer rate and nitrogen use efficiency of Pinus tabulaeformis were higher at mid-altitude than at low altitude or high altitude. Leaf nitrogen content at different altitudes varied from May to August, with no significant difference. Leaf thickness increased with altitude, but chlorophyll content and photosynthetic optimum temperature decreased with altitude. The change of photosynthetic altitude in Pinctada caerulea is related to the biochemical efficiency and nitrogen content of the leaves, but not to the specific leaf weight. The results showed that the elevation of temperature had a significant effect on the photosynthesis and leaf traits of Quercus acutissima, and the most suitable range of the altitude for obtaining and growing photosynthesis of Quercus mongolica was 3180 ~ 3610m.