旱稻叶片净光合速率日变化及其与影响因子关系的研究

以旱稻品种"特优13"、"旱稻15"为试材,研究其在旱作条件下灌浆期叶片光合日变化特性及其与影响因子的关系。结果表明:2个旱稻品种净光合速率的日变化曲线均呈"双峰"型,正午时出现光合"午休"现象,但"旱稻15"净光合速率日平均值大于"特优13","旱稻15"的水分利用效率显著强于"特优13"。经相关性分析,在自然条件下,净光合速率(Pn)与光合有效辐射(PAR)、蒸腾速率(Tr)、气孔导度(Gs)呈正相关,与胞间CO2浓度(Ci)呈负相关,与水分利用效率(WUE)的相关性不显著。根据Pn、Gs、Ci的变化趋势,推测旱稻的光合"午休"主要受气孔因素限制。

Diurnal Variation of Net Photosynthetic Rate of Upland-Rice Leaves and Its Relationship with Its Influencing Factors

Two upland-rice varieties(Te-you13,Upland-rice15)were grown in upland conditions,and photosynthesis characteristics and changes of accumulative product of grains in filling stage were studied.The results were summarized as follows: the curves of diurnal variation in the photosynthetic rate of two upland-rice leaves had two peaks and an obvious midday depression at 12:00,although the average photosynthetic rate of upland-rice15 was higher than Te-you13 in a day;the water use efficiency of upland-rice 15 was higher than Te-you13. Under natural conditions,the net photosynthetic rate was significantly positively correlated with photosynthetic active radiation.transpiration rate and stomata conductance,but the net photosynthetic rate was significantly negatively correlated with intercellular CO2 concentration,and was never significantly correlated with water use efficiency by correlation analysis.Based on the tendency of changes in Pn,Gs and Ci,the midday depression in the upland-rice was speculated to have been controlled by stomatal factors.