作　　者： ; ; ; ; (张亚光）;

机构地区： 华南农业大学生命科学学院

出　　处： 《草业科学》 2008年第6期34-38,共5页

摘　　要： 在自然状态下,利用Licor-6400便携式光合测定系统观测了公农1号紫花苜蓿Medicago sativa在北京地区的光合作用日变化规律。结果表明:公农1号叶片的净光合速率日变化呈典型双峰曲线,表现出明显的光合"午睡"现象,光合效率午间明显降低;蒸腾速率日变化趋势与净光合速率相似,胞间CO2浓度的日进程基本与净光合速率相反;气孔导度日变化与净光合速率日变化相似但并不完全同步,两者最大值出现的时间相同,但最低值出现的时间气孔导度较净光合速率晚约2 h。经分析,公农1号紫花苜蓿表现出的光合"午睡"现象属于非气孔限制。 Diurnal variations of leaf photosynthesis of alfalfa Gongnong No. 1 were studied by Licor- 6400 portable photosynthetic system in Beijing under natural condition. The results showed that the curve of diurnal variation in net photosynthetic rate （Pn） of the alfalfa leaves was dual-peaked with obvious midday depression of the photosynthesis efficiency. The diurnal variation trend of transpiration rate （E） was similar with that of Pn and the diurnal variation of internal cellular C02 concentra-tion （Ci） was just opposite to that of Pn. The diurnal variation between stomata conductance （Gs） and Pn were similar but not synchronism and their maximums appeared at the same time, the mini-mum of Gs was 2 hours later than Pn. Based on the analysis it was concluded that the midday depression of photosynthetic efficiency was mainly influenced by the non-stomatal limited factors.

关 键 词： 公农 号紫花苜蓿 光合作用 日变化

领　　域： [生物学] [农业科学]