6个不结球白菜品种光合作用特性的研究

Photosynthetic Characteristics of Six Brassica campestris ssp.chinensis Varieties

对6个不结球白菜品种的光合作用特性进行了研究.结果表明,在800μmol·m^-2·s^-1的光强下,不结球白菜的净光合速率以‘正大抗热青3号’最高,达16.37μmol CO2·m^-2·s^-1,其光合作用表观量子效率、羧化效率和水分利用效率也最高,分别为0.044 2、0.085 4 mol·m^-2·s^-1和6.20μmol CO2·mmol^-1 H2O;暗呼吸速率以‘绿星’最低,为2.24μmol CO2·m^-2·s^-1;Pn-PFD响应曲线显示,在光强300μmol·m^-2·s^-1以下,各品种的净光合速率差异较小,在光强为300～1 000μmol·m^-2·s^-1区段时,净光合速率随着光照强度增加而迅速增加.‘正大抗热青3号’光饱和点最高,达1 910.3μmol·m^-2·s^-1,其光饱和点的净光合速率也最高,达20.2μmol CO2·m^-2·s^-1;不结球白菜不同品种净光合速率日变化进程相似,不论数值高低均呈双峰曲线型,有明显的“午休”现象.

The photosynthetic characteristics of six Brassica carnpestris ssp. chinensis varieties were studied and the results indicated that at the light intensity of 800 μmol · m ^-2 · s ^-1,＇Zhengda kangre qing No. 3＇ had the highest net photosynthetic rate,which amounted to 16.37 μmol CO2 · m^-2 · s^- 1,and its apparent quantum yield,carboxylation efficiency and water use efficiency were the highest amounting to 0. 044 2, 0. 085 4 mol· m^-2 · s^-1 and 6.20 μmol CO2 · mmol^1H2O; ＇Lüxing＇ had the lowest dark respiration rate, which amounted to 2.24 μmol CO2 · m^-2 · s^- 1. Pn-PFD curves indicated that where the light intensity was below 300 μmol· m^-2 · s^- 1 ,the varieties slightly differed in net photosynthetic rate and where the light intensity changed from 300 μmol· m^-2 · s^- 1 to 1 000 μmol· m^-2 · s^- 1 they quickly increased their net photosynthetic rates. ＇Zhengda kangre qing No. 3＇ had the highest light saturation point amounting to 1 910. 3 μmol · m^-2 · s^- 1 and its net photosynthetic rate was the highest reaching 20.2 μmol CO2 · m^-2 · s^- 1 at the light saturation point ;The varieties showed similar daily net photosynthetic rate patterns which ,no matter the photosynthetic rate was high or low,were a double peak curve that indicated remarkable midday depression.