Effects Of Different Proportions Of Red And Blue Light On Growth And Quality Of Lettuce

Lettuce(Lactuca sativa L.),also known as leaf lettuce,contains many substances beneficial to the human.In recent years,the market demand for lettuce has been increasing,and the requirement for its quality and safety has been increasingly raised.Therefore,it is necessary to take the appropriate measures to realize the annual production of lettuce and increase the productivity and quality.This study mainly explores the effects of different light treatments on the growth and quality of different lettuce varieties through light quality control techniques.This study was carried out in a closed artificial light plant factory,using ’Locarno’,’Flandria’,and’Green Oak Leaf lettuce as experiment materials,applying LED as light source and set 11 light formulas with R:B=100:0(R),90:10(90%R),80:20(80%R),70:30(70%R),60:40(60%R),50:50(50%R),40:60(40%R),30:70(30%R),20:80(20%R)and 10:90(10%R),the control with 0:100(CK),light intensity of all treatments is 200 μmol·m-2·s-1.Exploring the effects of different red-blue proportions on the growth and quality of different lettuce varieties and providing appropriate lighting environment parameters for different lettuce varieties cultivated under plant factory conditions.The main results were:1.The biomass of Locarno and Flandria lettuces was the maximum under 90%R treatment and the minimum under CK.The biomass of’Green Oak Leaf was the maximum under 80%R treatment and the minimum under blue light.The plant height and plant width of lettuce were the maximum under R treatment but minimum under CK treatment.2.The blue light could promote the synthesis of photosynthetic pigments in lettuce,the photosynthetic pigment content of lettuce was maximum under CK treatment and the minimum under R;the blue light could reduce the crude fiber content of lettuce,the content of crude fiber were lower under the combination of red and blue light based on blue and blue light;the red light could reduce the nitrate content of lettuce,the nitrate content of lettuce was lower under the combination of red and blue light based on red and red light.3.Vitamin C content of Locarno and Flandria lettuce were higher under the red light and the combination of red and blue light based on red but less under blue light;vitamin C content of ’Green Oak Leaf lettuce was just the opposite,the content of vitamin C were higher under the blue light and the combination of red and blue light based on blue but less in red light.4.The combination of red and blue light based on red and red light could promote starch,Soluble sugar synthesis,the content of starch and soluble sugar in lettuce were all higher under the combination of red and blue light based on red and red light,and less under blue light.In terms of a single red light and blue light,combination of red and blue light was more conducive to promoting the growth and quality of lettuce,and the optimum proportion of red and blue light was different for different varieties of lettuce.Taking into consideration the growth indicators and physiological indicators of lettuce,the optimal proportions of red and blue light for Locarno was 80%R,Flandria was 90%R,and Green Oak Leaf lettuce was 70%R.Therefore,different production purposes can be achieved by choosing lettuce varieties and light qualities during the actual production.