四个大白菜品种光合日变化比较

Comparison of Four Chinese Cabbage on Daily Dynamics of Photosynthesis

以"金春2号"、"金夏55"、"金夏50"和"金秋55"4个大白菜品种为试材,在大田栽培条件下,用LI-6400便携式光合仪测定了光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)等生理因子以及光合有效辐射(PAR)、田间CO2浓度(Ca)、相对湿度(RH)、大气温度(Ta)等环境因子的日变化,以期为生产上大白菜的品种选择和栽培管理提供参考依据。结果表明:除"金秋55"的蒸腾速率日变化为"单峰"曲线外,其它品种的光合速率、蒸腾速率、气孔导度日变化均呈"双峰"曲线,存在着明显的"午休"现象;不同品种的光合速率、蒸腾速率、气孔导度的峰值和低谷出现的时间及值不同;相关分析表明,光合速率与环境因子的相关性小于蒸腾速率与环境因子的相关性。

Taking 4Chinese cabbage varieties of‘Jinchun No.2＇,‘Jinxia No.55＇,‘Jinxia No.50＇,‘Jinqiu No.55＇as materials,in field,the diurnal dynamics of photosynthetic rate（Pn）,transpiration rate（Tr）,and stomatal conductance（Gs）,as well as those of photosynthetic active radiation（PAR）,CO2 concentration in field（Ca）,relative humidity（RH）and air temperature（Ta）were measured using portable LI-6400 photosynthesis system.The results showed that,the curves of the diurnal variation in Pn,Tr and Gs of four Chinese cabbage varieties had two peaks except the curves of the diurnal variation in Tr of‘Jinqiu No.55＇had one peak,and an obvious midday depression;there were differences in the time and the value of the peaks in Pn,Tr and Gs of four chinese cabbage;correlation analyses showed that the correlation between Pn and environment factors was less than the correlation between Tr and environment factors.