| Tomato is one of the most widely cultivated vegetables in north china,as a typical thermophilic vegetable.Inefficient supply of CO2 caused by preserving heat via reducing ventilation in winter and spring inhibits the yield and quality of tomato in north China.To solve the problem,with tomato cv.'Xing-hai 12'as test material,The greenhouse was divided into four independent compartments with plastic film,each had a planting area of 52 m2.Taking air CO2 400?mol·mol-1(C0)as control,CO2 levels of 600?mol·mol-1(C1),800?mol·mol-1(C2)and 1000?mol·mol-1(C3)were setup in each compartment throughout the experiment from Nov 2016 to Apr 2017.Response of photosynthetic characteristics,chlorophyll fluorescence parameters,dry matter accumulation and fruit yield of tomato to interaction of CO2 supply was investigated.The suitable CO2 supply concentration for tomato production in greenhouse in winter and spring was studied for the greenhouse vegetable high yield and high efficiency production in north China.The main results as follows:1.The highest increment in cheight and stem diameter were obtained in treatment of C3(1000?mol·mol-1);the growth from the flowering stage to the young fruit stage was significantly higher than the seedling stage and the mature stage for the growth period.CO2 enrichment treatments significantly increased the photosynthetic pigment contents of tomato at all the tested growth stages,with the high increment at flowering and young fruit stage.The highest increment in chlorophyll a and chlorophyll b were obtained in treatment of C3(1000 ?mol·mol-1);the highest increment of carotenoid was CO2 800?mol·mol-1 at flowering stage and was 1000 ?mol·mol-1 at the other stages,and the flowering and fruiting period increased significantly compared with the seedling and maturation stages.2.With the increase of CO2 concentration,especially the C2 and C3 treatments significantly increased the chlorophyll content of tomato at different growth stages,and the Fo decreased significantly.The Y(?),Fv/Fm and qP were significantly increased in the increase of CO2 supply concentration,while the NPQ were significantly reduced in the increase of CO2 supply concentration.CO2 enrichment treatments can increase PSII activity by increasing the maximum quantum yield(PSII),and increase photosynthetic capacity and electron transfer rate by increasing qP and decreasing NPQ.3.The net photosynthetic rate,intercellular CO2 concentration and water use efficiency were significantly increased by CO2 supply at all the growth stages with the increase of CO2 concentration,and with the largest increment in the treatment of CO2 1000?mol·mol-1,and followed by the CO2 800?mol·mol-1.The stomatal conductance and transpiration rate were significantly reduced in the increase of CO2 supply concentration.Supplying CO2 increased the light saturation point,maximum net photosynthetic rate and apparent quantum efficiency,but decreased the light compensation point in tomato leaves to some extent,the best effects were all in the treatment of CO2 1000 ?mol·mol-1,and followed by CO2 800?mol·mol-1.For the all growth period,the photosynthetic potential of greenhouse tomato during the flowering period is stronger than during the seedling and maturation stages.4.CO2 enrichment treatments can improve the net photosynthetic rate of tomato leaves by decreasing the stomatal conductance and transpiration rate,thereby promoting the plant dry matter accumulation and yield increase.And increasing CO2 application has a greater impact on the yield of greenhouse tomato.Under the experimental range of CO2 supply,800?1000 ?mol·mol-1 of CO2 supply is recommended for high tomato yield,and the average yield was 93996 kg/hm2,which was 33.50%higher than the control treatment.Therefore,increasing the CO2 concentration of 800-1000 ?mol·mol-1 can facilitate the high-yield and high-efficiency production of greenhouse tomato. |
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