Effects Of High Temperature And CO₂ Enrichment On Growth Physiological Characteristics And Yield Of Cucumber In Greenhouse

In this experiment,the main greenhouse cucumber variety "Jinyou 35" in the northern greenhouse was used as the test material.A total of four groups of experiments were designed.One CK group was normal temperature(NT)and the three treatment groups were normal temperature CO2 enrichment(NT+CO2),High temperature CO2 enrichment(HT+CO2),high temperature(HT).The normal temperature of the test is controlled at 27±4℃,the high temperature is controlled at 3 7±4℃,the CO2 concentration is controlled at 1200ppm±200ppm,and the sunny day temperature and CO2 concentration treatment are controlled at about three hours during the test.Through the experimental method of high temperature stress combined with increased CO2 application,the morphological characteristics,photosynthetic characteristics,chlorophyll fluorescence parameters,phytohormone content,active oxygen metabolism system,osmotic adjustment substance,membranous peroxide content and yield Research on the impact of economic benefits,etc.came to the following conclusions;(1)High temperature CO2 enrichment treatment can promote the growth and development of greenhouse cucumbers.The leaf area and stem thickness of cucumbers are HT+C02>NT+CO2>CK>HT;plant height from high to low is NT+CO2>HT+CO2>CK>HT.The leaf area and stem thickness of HT+CO2 treatment were the largest,and the plant height was also significantly higher than CK.(2)High temperature CO2 enrichment treatment can increase the photosynthetic performance of greenhouse cucumbers.Cucumbers in different treatments showed HT+C02>NT+C02>CK>HT after 30 days of treatment.High temperature treatment resulted in net photosynthetic rate,leaf stomatal conductance(GS),and leaf intercellular CO2 concentration(Ci)significantly decreased compared with CK,but the chlorophyll content,net photosynthetic rate,leaf stomatal conductance(GS),and leaf intercellular CO2 concentration(Ci)of cucumbers with high temperature CO2 enrichment were significantly increased compared with CK.(3)High temperature CO2 enrichment treatment can increase the chlorophyll fluorescence performance of greenhouse cucumber.After 30 days of treatment in greenhouse cucumbers,the chlorophyll fluorescence parameters PS Ⅱ maximum photochemical efficiency(Fv/Fm),photochemical quenching(qP),and relative photosynthetic electron transfer efficiency(ETR)of cucumber leaves in each treatment greenhouse were as follows HT+CO2>NT+CO2>CK>HT,and HT+CO2 treatment is significantly higher than CK and HT treatment;non-photochemical quenching(NPQ)from high to low is H+CO2>HT>NT+CO2>CK,And HT+CO2 treatment is significantly higher than CK.(4)The effects of plant hormones on cucumber leaves in greenhouse under different treatment conditions are significantly different.Under the condition of high temperature treatment,the content of JA and ABA in cucumber leaves increased significantly compared with CK,while the content of IAA and ZR decreased significantly compared with CK;under the condition of HT+CO2 treatment,there was no significant difference between the content of ABA in cucumber leaves and CK.The JA content is significantly reduced compared to CK,the IAA and ZR content is significantly reduced compared to CK but is significantly higher than high temperature treatment;room temperature CO2 treatment conditions ABA content is significantly reduced compared to CK,JA content is not significantly different from CK,IAA Compared with CK,ZR content increased significantly.(5)High temperature CO2 enrichment treatment can enhance the active oxygen metabolism system of cucumber leaves,reduce the content of osmotic adjustment substances and the content of membrane peroxides.Under high temperature conditions,the addition of CO2 treatment significantly reduced the damage caused by high temperature to the cucumber leaves in the greenhouse,enhanced the ability of cucumber plants to withstand high temperature stress,and significantly improved the heat resistance of cucumbers.(6)High-temperature CO2 enrichment treatment improves the significant yield and economic benefit of greenhouse cucumbers.HT+CO2 treatment significantly increased the number of cucumber plants per plant,seed setting rate,plant weight per plant,yield per mu and economic benefits,and the addition of CO2 treatment not only solved the effect of high temperature reduction Compared with the control,it also increased the income by 38.27%,and compared with the high temperature stress,the net income increased by 81.36%.To sum up:After a certain period of time of increasing CO2 and high temperature treatment,cucumber in solar greenhouse can lead to the stem thickness,plant height,and leaf area of photosynthetic leaves of greenhouse cucumber plants after increasing CO2 application and high temperature treatment for a certain period of time.Maintain normal and stable growth and development,enhance the ability of cucumber plants to withstand high temperature stress,significantly improve the heat resistance of cucumbers,and ultimately show that the cucumber production in the greenhouse is greatly increased and the economic benefits are improved,so it is suitable for summer greenhouse cucumber production in the northern region Promotion in the application.