山东石灰岩山地混交林和纯林中侧柏生理特性比较

Physiological Characteristics Comparison of Mixed and Pure Forest of Platycladus orientalis in Shandong Limestone Mountain

[目的]探讨不同造林模式(侧柏纯林、侧柏-油松混交林)对侧柏生理特性的影响,为当地荒山造林方式的选择提供理论根据。[方法]于4月26与27日分别从早上8点到下午6点每隔2 h测定侧柏纯林和侧柏-油松混交林中侧柏的光合及蒸腾特性,对侧柏与油松的混交林以及侧柏纯林的光合特性、蒸腾特性以及叶片水分特性进行了分析研究。[结果]混交林中侧柏的净光合速率日变化、蒸腾速率日变化,以及光合速率与光照强度、空气温度、空气湿度、叶室温度、空气中CO2浓度等生态因子的相关性与纯林侧柏均不相同。1 d中光合速率平均值,纯林侧柏仅为混交林侧柏的54.1%;以鲜重为基础和以干重为基础的叶子含水量混交林侧柏与纯林侧柏相比差异不明显,但混交林侧柏的相对含水量明显高于纯林侧柏,而其叶片的自然饱和亏明显低于纯林侧柏叶片。[结论]在良好的森林小气候,有较高土壤水分条件下,旱季混交林林木的水分平衡状态好于纯林。

[Objective] To analyze the effect of different afforest model to barren hill on physiological characteristics of Platycladus orientalis,provide the theoretical basis for afforestation.[Method] Photosynthesis and transpiration were ascertained by measuring from 8 am to 6 pm every two hours in April 26 and 27,2004,the photosynthesis characteristics,transpiration characteristics and moisture content characteristics in leaves of Platycladus orientalis in mixed Platycladus orientalis-Pinus tabulaeformis forest and in pure Platycladus orientalis forest were investigated.[Result] The diurnal changes of net photosynthesis rate and transpiration rate of Platycladus orientalis in mixed Platycladus orientalis-Pinus tabulaeformis forest were different from pure Platycladus orientalis forest,as well as the relativity between photosynthesis rate of Platycladus orientalis in mixed forest and light intensity,air temperature,air humidity,the temperature of leave chamber and CO2 content in air.The mean photosynthesis rate of pure forest was 54.1% of the one of the mixed forest.The moisture content in leaves of two type of forest had not marked difference.Relative moisture content in the leaves of mixed forest was higher than that of pure forest,while its natural water saturation deficiency was lower than that of pure forest.[Conclusion] Under a good forest microclimate condition or with much soil moisture,the state of water balance for mixed forest was better than that of pure forest.