【摘要】 在透光率为74%的大棚膜覆盖基础上,以不覆盖遮阳网为对照（CK）,分别设置T1（2针,遮阳率10%）、T2（3针,遮阳率20%）和T3（4针,遮阳率40%）的3个遮阳网覆盖处理,研究不同光照度对快白菜光合特性及叶绿素荧光日变化的影响。结果表明,遮阳网处理的快白菜产量以及可溶性糖、可溶性蛋白和总酚含量降低,降幅均以T3处理的最大;叶片光合色素含量增加;蒸腾速率（T_r）、气孔导度（G_s）、胞间CO₂浓度（C_i）增加,但净光合速率（P_n）和水分利用效率（WUE）降低,其中T3处理的P_n和WUE显著降低;暗呼吸速率（R_d）、光补偿点（LCP）、最大净光合速率(P_{n max})、光饱和点（LSP）降低,表观量子效率（AQY）增加,T2和T3处理的R_d、LCP、LSP显著降低;表现电子传递效率（ETR）增加,初始荧光（F_o）降低,同时降低F_o和F_v/F_m在11:30和13:30的变化幅度,T2和T3处理的F_o和F_v/F_m变化幅度小。合适的遮阳率对快白菜产量和品质影响较小,同时可以减小午间高温强光导致的光抑制及PSⅡ反应中心损伤程度,以T2处理效果较好。更多还原

【Abstract】 To study the effect of different illuminance on photosynthetic characteristics and diurnal changes of chlorophyll fluorescence of Chinese cabbage,the greenhouse film which was 74%light transmittance was used,noshading net was set as control（CK）,3 shading net treatments were set（T1:shading rate was 10%,T2:shading rate was 20%,T3:shading rate was 40%）in this research..The results showed that shading net treatments were found adverse effects on the yield,soluble sugar,soluble protein and total phenolic content of Chinese cabbage,and those of the T3 treatment were found the largest decrease.Under Shading net treatment,the photosynthetic pigments were increased,the transpiration rate（T_r）,stomatal conductance（G_s）and intercellular carbon dioxide concentration（C_i）were also increased,while the photosynthetic rate（P_n）and water use efficiency（WUE）were significantly less than the control,which led to the decreases of the dark respiration rate（R_d）,light compensation point（LCP）,maximum net photosynthetic rate(P_nmax)and the light saturation point（LSP）,but the increase of apparent quantum efficiency（AQY）.R_d,LCP and LSP of the T2and T3 treatments were all decreased significantly.After shading net treatment,the ETR was increased,F_owas decreased,the amplitude variations of F_oand F_v/F_mat 11:30 and 13:30 were decreased,while the rangeability of T2 and T3 were small.To sum up,the yield and quality for Chinese cabbage were little affected by shading rate,the photo inhibition degree and the PSⅡreaction center damage could be decreased by high temperature and high light,and the T2 treatment showed the proper treatment effect.更多还原