环境因子对毛乌素沙地紫穗槐光合、蒸腾速率的影响

The Influence of Environment Factors on Photosynthetic and Transpiration Rate of Amorpha fruticosa in Maowusu Sandland

用L i-6400便携式光合仪,于2004年6—9月测定了毛乌素沙地紫穗槐的光合速率与蒸腾速率,研究了光合速率和蒸腾速率日变化特征及环境因子对其的影响,结果表明:光合速率日变化在6、7月呈双峰型,峰值分别出现在8:00和18:00时,在8、9月呈单峰型,最大值出现在12:00时;蒸腾速率日变化在6、7月呈双峰型,6月峰值分别出现在10:00和18:00时,7月峰值分别出现在10:00和16:00时,低谷都出现在14:00时,在8、9月呈单峰型,峰值出现在12:00时;8月是光合速率和蒸腾速率最大的月份,分别为15.48μmol.m-2.s-1、5.87 mmol.m-2.s-1。在土壤含水量和光强适宜的情况下,空气湿度对紫穗槐光合速率和蒸腾速率的影响大于温度;在6—9月,紫穗槐的水分利用效率呈现波动,表明其光合速率、蒸腾速率受环境影响较大。

The Li-6400 portable photosynthesis system was used for the dynamic research of photosynthesis and transpiration of Amorpha fruticosa in Maowusu sandland, and the environmental factors were recorded at the same time. This paper analyzed the diurnal change of photosynthesis and transpiration of Amorpha fruticosa and the effect of environmental factors. The results indicated that the photosynthetic rate displayed two-peak pattern in June and July and the peaks were at 8：00 and 18：00, and it displayed one-peak pattern in August and September and the peak was at 12：00. The transpiration rate displayed two-peak pattern in June and July and the peaks were at 10：00 and 18：00 in June and at 10：00 and 16：00 in July, and it displayed one-peak pattern in August and September and the peak was at 12：00. The highest photosynthetic and transpiration rates were in August and they are 15.48 μmol·m^-2·s^-1 and 5.87 mmol·m^-2·s^-1. Under the favorable conditions of soil moisture and light, the photosynthetic and transpiration rates were affected by air humidity obviously. In different months, the water use efficiency of Amorpha fruticosa was fluctuated, and this indicated that photosynthesis and transpiration were affected by environmental factors.