UV-A补光对LED红蓝光照射下的紫叶生菜生长和品质的影响

Effects of UV-A Supplemental Light on Growth and Quality of Purple Leaf Lettuce under LED Red and Blue Light Irradiation

在环境可控的密闭植物工厂内,采用LED红蓝光供光与UV-A补光相结合的供光模式,研究了采收前UV-A整体补光和UV-A局部补光对LED红蓝光照射下的紫叶生菜生长和品质的影响。常规光源采用红蓝配比4:1的LED光源,光强为200μmol·m^(-2)·s^(-1),光周期为12 h,光照时间为03:00~15:00。试验共设置3种光处理,处理1,光强、光质和光周期恒定不变,后期不做补光处理,记作CK;处理2,定植15 d后进行UV-A补光,采用UV-A灯整体补光,每天LED红蓝光光照结束后使用UV-A灯补光3 h,光强为30μmol·m^(-2)·s^(-1)处理6 d,记作UV-A;处理3,定植15 d后进行UV-A补光,采用UV-A灯局部补光(一半叶片被反光膜遮挡),每天LED红蓝光光照结束后使用UV-A灯补光3 h,光强为30μmol·m^(-2)·s^(-1)处理6 d,记作UV-AP(其中局部补光一侧记作UV-APL,局部遮光一侧记作UV-APD)。结果表明,与处理1相比,UV-A和UV-AP对紫叶生菜的生物量均无显著提高,UV-APL和UV-APD显著提高了可溶性糖含量且二者之间无显著性差异,各处理间硝酸盐含量无显著差异;UV-APL和UV-APD对花青素、AsA、总酚和类黄酮的响应一致且二者之间无显著性差异;与处理1相比,UV-A显著提高了次生代谢物的积累量。总之,通过采前短时、低剂量的UV-A补光可以显著提高紫叶生菜的品质,植物工厂生菜生产采前UV-A补光运用有很大前景。

In a closed plant factory under controlled environment,the effects of UV-A global and UV-A local light supplementation before harvesting on the growth and quality of purple leaf lettuce under LED red and blue light irradiation were studied by combining LED red and blue light supply with UV-A light supply.The conventional light source uses a red and blue ratio of 4:1 LED light source,light intensity of 200μmol·m^(-2)·s^(-1),photoperiod of 12 h,light time 03:00~15:00.Three light treatments were set up in the experiment.In treatment 1,the light intensity,light quality and photoperiod were constant and no light supplement was done in the later stage,which was denoted as CK.In treatment 2,UV-A lighting was performed 15 days after colonization.UV-A lighting was used as the global lighting.After the end of LED red and blue light illumination,UV-A lighting was used for 3 h for 6 days with a light intensity of 30μmol·m^(-2)·s^(-1),which was recorded as UV-A.In treatment 3,UV-A supplementary light was performed 15 days after colonization,and UV-A supplementary light was used locally(half of the leaves were blocked by reflective film).After the end of LED red and blue light,UV-A supplementary light was used for 3 h every day,and the light intensity was 30μmol·m^(-2)·s^(-1)for 6 days,which was recorded as UV-AP(one side of local supplementary light was recorded as UV-APL.The partial shading side is known as UV-APD).The results show that compared with treatment 1,UV-A and UV-AP do not significantly increase the biomass of purple leaf lettuce,UV-APL and UV-APD significantly increases the soluble sugar content,and there is no significant difference in nitrate content between the two treatments.UV-APL and UV-APD have the same response to anthocyanins,AsA,total phenols and flavonoids,and there is no significant difference between them.Compared with treatment 1,UV-A significantly increases the accumulation of secondary metabolites.In conclusion,the quality of purple leaf lettuce can be significantly improved by short-term,low-dose UV-A lighting before harvest,and the application of UV-A lighting before harvest in lettuce production in plant factories has a great prospect.