Effects Of Interaction Of Elecvated CO₂ And LED Supplement On Photosynthesis And Yield And Quality Of Greenhouse Tomato

Tomato is one of the most widely cultivated vegetables in the world,the weak light and CO₂ "hunger" caused by preserving heat via reducing ventilation in autumn and winter inhibits the yield and quality of tomato in northern China.To solve the problem,with tomato cv.Jin-Peng 1 as test material,this study adopted a split plot design with CO₂ at three concentrations as the main plot?C1,C2,C3: ambient CO₂,800 ?L/L and 1200 ?L/L,respectively?and light at two intensities as subplots?L1,L2: natural light,natural light and LED light supplement of 100 ?mol/?m2.s?,respectively?with six treatments.Response of photosynthetic characteristics,dry matter accumulation,fruit yield and quality of tomato to interaction of CO₂ enrichment and LED Light supplement was investigated.The aim of the study is to get the suitable CO₂ concentration and light condition for tomato production in greenhouse in autumn and winter,to achieve high yield and high efficiency production of greenhouse vegetables.The main results as follows:1.No significant effects of CO₂ enrichment and light supplement were observed on the content of Chla,Chlb and carotenoids,however,Chla/b of the nature light and elevated CO₂ to 800 ?L/L?L1C2,same as follows?and L2C3 decreased notably.When the light was at a certain level,Except for L2C2,stomatal limitation decreased significantly with the increasing of CO₂ concentration,while net photosynthesis?Pn?,intercellular CO₂ concentration?Ci?,stomatal conductance?Gs?and transpiration rate?Tr?were opposite,and L2C2 was mainly affected by stomatal limitation.2.Light supplement and elevated CO₂ significantly decreased stomatal density and enhanced the fresh weight and dry matter of tomato plants and yield.Effects of CO₂ enrichment on the fresh and dry weight and fruit weight and yield were more significantly than light supplement.Among all the treatments,L2C2 had the highest yield of 36349.33 kg/hm2,which increased by 34.11% compared with the control.3.L2C3 significantly improved the soluble solids,soluble protein and lycopene content in tomato fruit,and enhanced fruit weight fruit color,while reduced the content of nitrate nitrogen in fruit.4.CO₂ enrichment and LED light supplement increased the content of tomato characteristic compounds and types,such as 6-methyl-5-Hepten-2-one,trans-á-Ionone,Hexanal,which improved the tomato fruit fragrance.