黄土高原地区蒙农4号新麦草的光合特征及其与环境因子间的关系

The Relationships of Environmental Factors and the Photosynthetic Characteristics of Psathyrostachys juncea ‘Mengnong No.4' in Loess Plateau Region

为研究蒙农4号新麦草(Psathyrostachys juncea‘Mengnong No.4’)在黄土高原地区的适应性,以美国引入新麦草为CK,用CI-340光合测定系统对其进行光合特性的测定,比较光合日变化,并分析其与环境因子的相关性。结果表明:2份材料的净光合速率(Pn)日变化均为双峰曲线,呈现出明显的"午休"现象,但蒙农4号新麦草的Pn最大值以及日均值均高于CK;2份材料的蒸腾速率日变化一样,为单峰曲线,最高峰出现在15:00左右。蒙农4号新麦草的气孔导度和叶片水分利用效率均高于CK,说明其适应性和生产力均大于CK。蒙农4号新麦草的光补偿点低而光饱和点较高,对光的适应性强,适合在黄土高原地区种植。

In order to study Psathyrostachys juncea ‘Mengnong No.4’ adaptability in loess plateau region,the diurnal variation of photosynthesis was studied using the CI-340 photosynthesis measure system,with P.juncea introduce from America as control,then the relationships of photosynthetic characteristics and environmental factors were analyzed.The results showed that the diurnal variation of net photosynthetic rate （Pn） had a bimodal pattern and had a clear midday depression.The maximum and daily mean values of Pn in Psathyrostachys juncea ‘Mengnong No.4’ were higher than that in CK.The net photosynthetic rate was caused by stomatal and non-stomatal limitation.The change of transpiration rate was a single-peak curve,and the peak emerged at 15：00.The net photosynthetic rate,stomatal conductance and water use efficiency of P.juncea ‘Mengnong No.4’ were higher than that of CK.P.juncea ‘Mengnong No.4’ had lower light compensation point and higher light saturation point.Therefore,P.juncea ‘Mengnong No.4’ is suitable for planting in loess plateau region.