高寒地区川草1号老芒麦夏季光合生理生态特性的初步研究

Primary study on physiological and ecological characteristics of photosynthesis of Elymus sibiricus cv.Chuancao No.1 in summer in alpine area

对川草1号老芒麦Elymus sibiricus叶片光合日变化测定结果表明,晴朗天气条件下,川草1号老芒麦叶片净光合速率(Pn)日变化曲线呈双峰型,其峰值分别出现在11:30和16:30,2个峰值之间有1个低谷,出现在12:30附近;经相关性分析发现,各生理生态因子与Pn的相关性大小顺序为:气孔导度>叶片温度>光合有效辐射>蒸腾速率>饱和蒸汽压亏差>水分利用效率>大气CO2浓度>空气相对湿度>胞间CO2浓度,其中,气孔导度、太阳有效辐射与Pn的关系呈极显著正相关,是对川草1号老芒麦光合作用影响最为强烈的因子,而气孔导度下降导致气孔关闭,因此气孔导度是光合午休产生的主要原因。

The daily variation of photosynthesis in Elymus sibiricus cv. Chuancao No. 1 leaves was measured, which showed that under sunny days, Pn had two peaks, one at 11.30 am, the other at 16.30 pm, the bottom between thetwo peaks was at 12：30 pm. The physiological and ecological factors had correlation with Pn ranked as Cd 〉 Tl 〉 PAR 〉 Tr 〉 VpdL 〉 WUE 〉 CA 〉 RH 〉 Ci. Cd and PAR were significantly positive correlated to Pn, had the greatest influence on photosynthesis. Cd was the main reason of photosynthetic noon-break.