Different LED Light Source Effect For Lettuce’s Physiological And Quality Character

Light,air,temperature,water and fertilizer has long been considered needed for plant growth and development of the main environmental factors.Light as important physical environment factor,and play a crucial role of plant growth.However,different wavelengths of light in the process of plant growth and development of the role of is not the same.New Light source LED is a very stable Light source,its range of Light emission is less than 30 nm,it not only can emit pure color,but also can combination of two or more Light,since it has advantages of energy saving high efficient,is the study on the influence of different Light environment plants the best choice of the test.The test altogether conducted two repeated trials,Time is respectively in May 2016 to July,and in September to November 2016.Test set seven processing,LED light source processing respectively red light,blue light,yellow light,green light,purple light,red/blue(9:1)light,red/blue(1:4)light,with white LED light for comparison,for the "big American fast-growing" leaf lettuce as the experimental material,discusses different LED light source for leaf lettuce growth,physiological characteristics and the influence of the quality,in order to provide theoretical support of the light quality of high quality and high yield for leaf lettuce environmental regulation,and provide certain reference for the development of plant lettuce plants.Main results obtained are as follows:Under blue,purple and red/blue=1:4 processing of lettuce plant height,leaf thickness,aboveground fresh weight and leaf area were significantly higher than contrast white light,in addition to the purple light,the processing of leaf number and plant height is the lowest,but improves the yield of lettuce.under yellow light,red light and red/blue = 9:1 processing of plant height is higher than contrast white;leaf thickness,aboveground fresh weight,leaf area was significantly lower than contrast white;the processing of the light source of lettuce leaf number difference was not significant.and the green is the worst among all light.Along with the growth of lettuce,chlorophyll content showed a slow growth trend,under the red / blue =1:4 treatment of lettuce chlorophyll content was the highest,followed by blue light;SOD,POD and CAT activity showed increased first and then decreased,under the blue and red / blue =1:4 treatment of lettuce SOD and POD activity was significantly higher than contrast.Under the red light treatment of lettuce POD activity was significantly higher than contrast white light.Soluble sugar and soluble protein decreased with the growth of lettuce.Under the red light treatment of lettuce soluble sugar content showed obvious advantage in various stages of lettuce growth,followed by red blue light.About the lettuce soluble protein,blue and red / Blue 1:4 light was the optimal treatment effect.The content of Vc and nitrate content increased gradually,under the blue light treatment of lettuce Vc was significantly higher,under the yellow light and the green light treatment of lettuce Vc content was significantly lower than contrast.About the lettuce nitrate content,green light and yellow light was the highest,and the red light was the lowest.Anthocyanin content in the whole growth stage changed little.To sum up,the most appropriate lettuce growth LED light source is red/blue = 1:4;and after Transplanting 30 day is the best harvesting time.