Effects Of Different Light Quality And Photoperiod On Growth Of Cauliflower Seedlings

Vegetable seedling plays a very important role in vegetable production and directly affects the yield and quality of vegetables.Photosynthesis through light is the basis of plant growth and development.In order to promote photosynthesis in vegetable production,light supplement is widely used to improve yield and quality.The influence of different light quality on plant growth is also very different,so it is of great production significance to explore the reasonable light quality for the improvement of vegetable yield and quality.This study "tianjin 70" broccoli as experimental material,the light emitting diode（LED）light source,under the condition of the intensity of the different light quality（blue,red,red,blue,white,green）for broccoli seedling morphogenesis,photosynthesis and the influence of root system,and will select the best quality for later different light cycle test,The total light hours per day were 6h,12 h,16h and 18 h,respectively,in order to explore the difference of different light hours,seek the best efficiency combination,and provide theoretical basis for broccoli to cultivate strong seedlings.The test results are as follows:1.After 30 days of different light quality treatment,the plant height,stem diameter and leaf area of cauliflower seedlings were increased by 6.6%,38.26% and 20.4% under red-blue combined light（3R1B）condition,respectively.Under the condition of red-blue combined light（3R1B）,after 30 days of different photoperiod treatment,the plant height,stem diameter and leaf area of cauliflower seedlings under 12h/d treatment increased by 2.6%,4.7% and10.3%,respectively.2.There were significant differences in the effects of different light quality on antioxidant enzyme activities of cauliflower seedlings,and the 12h/d photoperiod treatment under red-blue combined light treatment significantly promoted antioxidant enzyme activities.POD,SOD and CAT increased by 9.33%,13.4% and 19.75% after 20 days of red-blue combined light treatment,respectively.APX increased by 10.68%,5.9% and 8.02% at 10,20 and 30 days,respectively.3.The soluble protein,soluble sugar,root activity and net photosynthetic rate of cauliflower seedlings treated with red-blue combined light（3R1B）for 12h/d increased by23.92%,15.15%,24.09% and 8.7%,respectively.Chlorophyll A content was increased by23.94%,29.31% and 33.11% under single blue light（B）,single red light（R）and red-blue combined light（3R1B）,and carotenoid content was increased by 14.96%,30.71% and42.52%,respectively.4.Red and blue combined light（3R1B）treatment for 12h/d significantly increased the dry fresh weight of abovementid and dry fresh weight of underground,and the seedling index increased by 7.2%.5.In terms of electricity consumption,the comparison of electricity consumption is 6h/d< 12h/d < 16h/d < 18h/d,but the treatment effect is 12h/d > 16h/d > 18h/d > 6h/d.It is concluded that the red-blue combination light（3R1B）12h/d is the most suitable for economy and efficiency.