大豆品种主要光合指标日变化的研究

Studying on Diurnal Variation of Main Photosynthetic Index of Different Soybean Varieties

为了探讨大豆品种光合作用的差异,在田间条件下,选用5个大豆品种,利用LI-Cor 6400光合测定仪对其开花期和结荚期的净光合速率、气孔导度、胞间CO2浓度及蒸腾速率的日变化进行了研究,同时比较了不同大豆品种的叶绿素含量。结果表明:开花期,大豆净光合速率和蒸腾速率呈典型双峰曲线变化,在10:00、15:00达到高峰;结荚期,净光合速率主要呈单峰变化,在10:00达到全天的最高值,蒸腾速率仍然表现为典型双峰曲线,但达到日变化最高值的时间比开花期提前了2h;气孔导度在早晨最高,9:00之后变化平缓;胞间CO2浓度在早晨和傍晚较高,在9:00-16:00内变化不大。大豆不同品种的叶绿素SPAD值在开花期无显著差异,在结荚期,中豆8号显著低于其他品种。研究表明,不同大豆品种之间的主要光合指标具有规律性。因此,选择高光效品种时应兼顾各项主要光合指标。

To investigate the differences between the photosynthetic characteristics of different soybean varieties,diurnal variation of main photosynthetic index was determined for five different soybean varieties by using LI-Cor 6400 portable photosynthesis system in the field condition at flowering and podding stage.And the content of chlorophyll was also determined.The results showed：At flowering stage,net photosynthetic rate and transpiration rate showed a typical bimodal curve,peaking at 10：00 and 15：00;At podding stage,the transpiration rate represented a typical diauxie curve,which reached its highest peak ahead of 2 h,however,the net photosynthetic rate was characterized by a unimodal curve with a peak at 10：00;The highest stomatal conduc-tance was in the morning,and changed slowly after 9：00;Intercellular CO2 concentration was higher in the morning and evening,with little change between 9：00 and 16：00;The SPAD Value of different soybean varieties had no significant difference at flowering stage,and Zhongdou No.8 was significantly lower than the other varieties at podding stage.The study showed that the diurnal variation of photosynthetic index had its regularity among five soybean varieties.It was concluded that the selecting of soybean varieties with high photosynthetic efficiency should take into account of various indicators of photosynthetic characteristics.