紫外线-B照射对小白菜生长、产量及品质的影响

在温室条件下，采用辐照度为0.4、0．5和0．6W·m^-2的紫外线-B（UV—B）对小白菜（Brassi cacampestrisssp．chinensis Makino）照射2、3和4h·d^-1，连续照射7d后，研究了UV—B照射对小白菜生长、产量及品质的影响。结果表明，停止照射后35d，各处理组小白菜的鲜质量、株高、叶片数、干物质含量、叶绿素含量、可溶性糖含量及硝酸盐含量均与对照无显著差异，但Vc含量增加，可溶性蛋白质含量降低。经UV—B照射后，下胚轴长度大于2cm的小白菜植株所占的百分率显著低于对照，说明UV—B照射可有效控制小白菜植株徒长。从子叶充分展开时用0，4—0．6W·m^-2 UV—B照射2h·d^-1，连续照射7d，既能有效控制小白菜植株徒长、提高Vc含量，又不会造成产量和品质的下降，为最佳的补充UV—B处理条件。

Effects of ultraviolet-B radiation on growth, yield and quality of pakchoi (Brassica campestris ssp. chinensis)

Plant growth, yield and quality of pakchoi （Brassica campestris ssp. chinensis Makino ） treating with 0.4, 0.5 and 0.6 W · m^-2 ultraviolet-B（UV-B）irradiated 2, 3 and 4 h· d^-1 successively for 7 days were studied in greenhouse. The results showed that there were not significant difference in fresh weight, height, leaf number, dry matter content, chlorophyll content, soluble sugar content and nitrate content of pakchoi between treatment groups and control group after 35 d of stopping irradiated, however, Vc content increased and soluble protein content decreased in treatment groups. After irradiated with UV-B, the percentage of pakchoi plant of hypocotylar length above 2 cm was significantly lower than the control, which indicated that UV-B irradiation treatment has a significant effect on controlling plant overgrowth. The best treatment condition is that pakchoi is irradiated 2 h·d^-1 with 0.4 -0.6 W · m^-2 UV-B successively for 7 days since cotyledons fully opened, which can be effective on controlling overgrowth and enhancing Vc content, while will not induce decline on yield and quality.