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作 者 ：徐丽君^1,2;王波³;孙启忠²

期 刊 ：应用生态学报 2008年 19卷 10期 页码：2189-2193

关键词：花苜蓿；

摘 要 ：利用Li-6400光合测定系统，田间实地测定了紫花苜蓿3个品种（敖汉苜蓿、Rangelander和 阿尔冈金）的光合作用日变化特征.结果表明:不同生长年限紫花苜蓿3个品种的净光合速率(P_n)、蒸腾速率(T_r)和水分利用效率(WUE)日变化并不完全呈双峰曲线.其中，敖汉苜蓿和阿尔冈金叶片的P_n和T_r峰值均出现在9:00—11:00,Rangelander在11:00,最低值均出现在7:00和19:00；Rangelander和阿尔冈金叶片的WUE最高值出现在7:00,敖汉苜蓿在9:00,最低值均出现在15:00—17:00.综合分析P_n、T_r和WUE 3项指标,2 年生苜蓿各项指标最佳,1年生次之,而4年生最差；对P_n和T_r影响最大的环境因子是气温,其次是水分亏缺和空气相对湿度.

Abstract:By using a Li-6400 portable photosynthesis system, the diurnal dynamics of the photosynthetic characteristics of three alfalfa varieties Medicago sativa L. cv. Aohan, M. sativa L. cv. Rangelander, and M. sativa L. cv. Algonquin were studied. The results showed that for the test alfalfa varieties, the diurnal variation curves of their P_n, T_r, and WUE were not all presented double-peak. For Aohan and Algonquin, the maximum P_n and T_r occurred at 9:00-11:00; while for Rangelander, they appeared at 11:00. The minimum P_n and T_r of the three varieties all appeared at 7:00 and 19:00. The maximum WUE of Rangelander and Algonquin appeared at 7:00 and that of Aohan was at 9:00, and the minimum WUE of the three varieties all appeared at 15:00-17:00. Comprehensive analysis on the photosynthetic performance indices P_n, T_r, and WUE indicated that 2 years old alfalfa was in the best state, followed by 1 year old, and 4 years old. Correlation analysis showed that air temperature (T_a) was the main environmental factor affecting P_n and T_r, followed by water vapor pressure deficit (VPD) and relative humidity (RH).

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