Effects Of LED Supplemental Lighting And Rhizosphere Temperature Regulation On Regeneration Of Hydroponic Lettuce In Summer

The adverse effects of high temperature on the growth of vegetables are the basic reasons for the summer and autumn off-season.The temperature in Hainan is high in summer and up to 60 degrees centigrade in the greenhouse.Under natural conditions,it is difficult to produce fresh vegetables such as lettuce in summer,and the supply of vegetables is difficult.Previous studies have shown that cutting and regeneration of lettuce in hydroponic culture which is easy to be specialized,standardized and intensi,ve,and it can be used as an effective way to solve the current market supply problems of cold and cold vegetables in the summer and autumn and high temperature off-season in Hainan.However,compared with the cold season,the yield and quality are not high of regeneration lettuce in hydroponics culture at high temperature.In order to solve the above problems,we use butter lettuce(Lactuca sativa.L.)as experimental material and try to improve the yield and quality of cutting and regeneration lettuce by regulating the environment of light and temperature.From the perspective of plant physiology,we analyzed the effects of light and Rhizosphere temperature regulation.We hope to get the appropriate LED supplement time,the suitable LED light intensity,suitable LED light quality,and the suitable rhizosphere temperature in the dark period of regeneration lettuce by hydroponic culture during the high temperature season in Hainan.Finally,we hope to get a brief technical system plan,which is to regulate and control LED's lighting and regulate the rhizosphere temperature for regeneration lettuce by hydroponic culture.The main results and conclusions of this study are as follows:The results of the light treatment test are as follows:After cutting lettuce,its growth conditions within natural light during the day,LED lamp during the night.According to the experiment,it is concluded that the best scheme for light:12h is the best,but the difference of yield and quality is not significant with 8h.From the perspective of actual production and energy saving,the suitable light time is 8h;the suitable light intensity is 200umol m-2s-1;the appropriate light quality ratio is:Red/blue =8.The effects of different temperature and nutrient solution on the growth,quality and physiological indexes of lettuce are different in the high temperature season of Hainan.In this experiment,different rhizosphere temperatures were set up during the growth of regeneration lettuce.The best is the rhizosphere temperature of 25? and L-25?treatments,and considering the need of energy saving in actual production,it is the best choice to d L-25? treatment.Referring to the results of previous studies and the special climate environment in Hainan,we studied the effects of different light and temperature on lettuce.The results are as follows:LT growth morphology index is significantly different from other treatments except for aboveground dry weight.The experimental conditions greatly promoted the growth and development of regenerated lettuce under the high temperature environment,shortened the production cycle and increased the yield,but the effect of improving the nutritional quality was not obvious.