日光辐射对老芒麦再生草光合特性的影响

采用CI 310便携式光合测定仪,分别在晴天和阴天对老芒麦再生草的净光合速率、光合有效辐射及蒸腾速率等相关生理生态指标进行测定。结果表明,在晴天和阴天不同日光辐射下,再生草净光合速率的日变化曲线呈双峰型,晴天有明显光合"午休"现象。相关分析结果表明,无论晴天或阴天,光合有效辐射和蒸腾速率与净光合速率相关性一致,其主导因子与净光合速率相关性排序为:光合有效辐射>蒸腾速率>叶片温度。其中可控因子是蒸腾速率,而蒸腾速率则与净光合速率呈正相关,因此保持老芒麦再生草旺盛的蒸腾速率是提高净光合速率的有效途径。

Study of Net Photosynthesis on Elymus sibiricus L. Regrowth Under Different Sunlight Radiations

Using a CI-310 portable photosynthesis detector, we measured the net rate of photosynthesis, the photosynthesis availability radiation, the transpiration rate, and other related ecophysiological factors of Elymus sibiricus L.in the agro-pastoral transitional zone in Fengning County of northern China's Hebei Province,both in sunny and cloudy days.The result shows that in both weathers,though of different sunlight radaitions,the diurnal variation of the net photosynthesis of Elymus sibiricus L.remains a double-peak curve.However,the net photosynthesis curve appearing in sunny days displays a significant noontime depression. Interrelated analyses conclude that,consistent correlations remain between ecophysiological factors such as photosynthesis availability radiation,transpiration rate,ect.and the net photosynthesis rate,whether it be cloudy or sunny.The sequence of relation between the leading ecophysiological factors and the net photosynthesis is:photosynthesis availability radiation(PAR)>transpiration rate>leaf temperature.The fact is:the transpiration rate is a controllable factor and closely related to net rate of photosynthesis.Consequently,an efficacious measure to invigorate the growth of Elymus sibiricus L.is to maintain its high rate of transpiration and net rate of photosynthesis.