3种灌木树种光合特性及影响因子研究

Photosynthetic Characters and Impact Factors of Three Flowering Shrubs

为量化研究城市森林固碳释氧能力,对沈阳城市森林中主要灌木树种——紫丁香(Syringa oblata)、连翘(Forsythia suspensa)和榆叶梅(Prunus triloba)不同季节光合速率的日变化与季节变化规律进行研究,并采用多元逐步回归统计分析方法,建立了净光合速率与生理生态因子关系模型。结果表明:春季和夏季紫丁香和榆叶梅光合速率日变化曲线呈双峰曲线,连翘呈单峰曲线;秋季光合速率日变化均呈单峰曲线。紫丁香净光合速率季节变化规律为:夏季>秋季>春季,连翘和榆叶梅的季节变化规律为:春季、夏季>秋季。春季、夏季光合速率主要受光合有效辐射、气孔导度的影响,秋季光合速率的直接影响因子为温度条件。

To quantize and study the ability of carbon fixation and transpiration in urban forest, diurnal and seasonal changes of photosyntheti~ rate in different seasons of main shrub species （Syringa oblata, Forsythia suspensa and Prunus triloba） in Shenyang was studied using LI-6400 IR gas analyzer （IRGA）, and using statistical method of multinomial regression, the related equation on net photosynthetic rate and environmental factors were also constructed. The results showed that the diurnal changes of photosynthetic rate of Syringa oblata and Prunus triloba in spring and summer presented double peak curves, while that of Forsythia suspensa was single peak curve; the diurnal changes of photosynthetic rate of the three shrubs in autumn were single peak curve. The seasonal changes of net photosynthetic rate of Syringa oblata was： summer〉autumn〉spring and that of Prunus triloba and Forsythia Suspensa in spring and summer was higher than in autumn. The photosynthetic rate in spring and summer were mainly affected by photosynthetic active radiation and stomata conductance, and the direct factor of the photosynthetic rate in autumn was temperature.