Effects Of CO₂ Fertilization On Growth Physiological Characteristics And Yield Of Grafted Cucumber And Self Cultivating Plants In Greenhouse

In this experiment,the black rooted pumpkin grafted seedlings?white seed pumpkin grafted seedlings and"Jinyou 35"self rooted cucumber seedlings were used as test materials,the CO₂ concentration was 500-700 mg/kg^-1?B1?,700-900 mg/kg^-1?B2?,900-1200 mg/kg^-1?B3??300-400 mg/kg^-1?CK?and the effects of CO₂ fertilization on growth,physiological characteristics,yield,quality and economic benefits of Cucumber were studied in the greenhouse.?1?The growth of cucumber were promoted by CO₂.In B2 and B3 treatments,The plant height of self root,white seed and black seeded cucumber were highest,and all showed upward trend along with the growth and the development of cucumber.The height of self root cucumber was significantly lower than that of white seed and black seed,especially the black seed.The height of black seed was 17.19%and 5.80%higher than that of white seed and self root.CO₂ fertilization significantly increased the stem diameter of self root cucumber,white seed and black seed,increased 5.43%-15.43%,7.75%-16.32%and 9.75%-17.98%;The black seeds increased by 3.07%and 11.90%compared with white seeds and self root cucumber.Meanwhile,CO₂ fertilization significantly increased the leaf area of self root,white seed and black seeded cucumber,and increased 5.43%-15.43%,7.75%-16.32%and 9.75%-17.98%respectively.?2?The concentration of CO₂ was increased in greenhouse,and it was provided a sufficient substrate for photosynthesis.The chlorophyll SPAD value,net photosynthetic rate and leaf starch content of the self root cucumber,white seed and black seed were improved when the CO₂ was used,it was increased by 7.57%-21.47%,10.75%-29.42%and7.43%-30.02%,23.96%-95.37%,21.76%-89.15%and 26.58%-65.85%,9.17%-32.75%,14.10%-35.04%and 11.98%-34.71%,respectively.Stomatal conductance and transpiration rate was decreased.?3?The stress resistance of white seed and black seeded cucumber were significantly increased by CO₂,and the activities of SOD and POD in cucumber leaves were increased.The self root cucumber increased by 6.69%-24.44%,11.29%-38.68%,white seed increased by 6.07%-26.34%and 9.61%-32.24%respectively,and black seed increased by10.62%-22.65%and 6.65%-27.25%.The soluble sugar of leaf of white seed and black seed increased by 8.75%-19.09%,8.31%-14.70%and 8.50%-14.99%respectively;The activities of SOD,POD and soluble sugar in leaves of black seed cucumber were significantly higher than those of white seeds and self rooted ones.The content of MDA in leaves were reduced by CO₂,The content of MDA of black seed was 2.20%and 5.37%lower than that of white seed and self rooted cucumber.The photosynthesis and starch content of different treatments were better than those of B2.The effects of different grafting materials were black seed>white seed>self root.?4?The photosynthesis of cucumber plants were promoted by CO₂,and then increased cucumber yield and optimized yield components.The yield of self root cucumber,white seed and black seed increased by 9.71%-30.94%,9.25%-31.23%and 11.60%-30.38%respectively;The yield of black seed increased by 1.62%and 5.27%compared with white and self rooted cucumber.CO₂ fertilizer significantly promoted melon length,melon thickness,single melon weight and melon number per plant.At the same time,CO₂fertilization improved the economic benefits of self-root,white-seed and black-seed cucumber.Thenetincomealsoincreased870.35-3395.36yuan·667m^-2,890.66-3525.25yuan·667m^-2 and 1233.37-3583.31 yuan·667m^-2.To sum up,the black seeded seedlings with CO₂ concentration of 700-900 mg·Kg^-1 are suitable for cultivation in the mid west cold areas of Inner Mongolia.