Effect Of Regulating Air Relative Humidity On Growth,water Status And Yield Of Muskmelon And Tomato In Greenhouse

The scientific regulation of greenhouse air relative humidity is one of the important technologies for realizing efficient management and high-quality production of facility agriculture.The greenhouse environmental impact of low air humidity in summer and high air humidity in winter has negative effects on crop growth.This article used greenhouse humidification regulated technology to explore how air humidity controls the water physiology and photosynthetic production of muskmelon and tomato in different growth stages.Finally aims to provide theoretical support and practical basis for the humidity environment regulation technology of muskmelon and tomato in greenhouse.This study includes two types of experiments in summer and winter.In the summer experiment,muskmelon"Yipin Tianxia"and tomato"Jinpeng No.10"were used as research objects.Summer experiment used greenhouse ultrasonic humidification technology to set up two air relative humidity treatments（30%and 70%）.To explore the effects of different air humidity on the growth,photosynthetic characteristics,water status,yield and quality of muskmelon and tomato in different growth stages in greenhouse.In the winter experiment,tomato"Jinpeng No.10"was used as the test material,and the greenhouse heating and dehumidification technology was used to study the effect of this technology on the dynamic changes of temperature and humidity in the greenhouse,tomato photosynthetic characteristics,and leaf anatomical structure.The main research results are as follows:1.Ultrasonic humidification treatment in summer greenhouse can alleviate the negative effects of atmospheric drought on crops,and has a greater impact on the blooming and fruit-setting stage and fruit enlargement stage of muskmelon.Compared with the control treatment,the humidification treatment significantly increased the photosynthetic rate and stomatal conductance of muskmelon leaves,and significantly reduced the transpiration rate.The study of the anatomical structure showed that the thickness of the leaf,the fence tissue and the sponge tissue were significantly increased under the humidification treatment.22.8%,8.2%and 10.3%,the cross-sectional area of the vascular bundle and the cross-sectional area of the duct within the stem increased significantly by 48.8%and 51.9%.Humidification treatment optimizes the water transport status of crops,and its relative leaf water content and leaf water potential are significantly higher than the control treatment at different growth stages.With the cumulative effect of humidification treatments at different growth stages on crops,the water consumption during the whole growth period of muskmelon under humidification treatment was significantly reduced by14.7%,the yield per plant of muskmelon was significantly increased by 9.9%,and the yield-water use efficiency of melon was significantly increased by 27.9%.2.The ultrasonic humidification treatment in summer greenhouse has a greater impact on the blooming and fruit-setting stage and fruit enlargement stage of tomato.Compared with the control treatment,the humidification treatment significantly increased the photosynthetic rate of tomato during flowering and fruit setting period by 20.9%,stomatal conductance by 13.0%,intercellular carbon dioxide concentration by 12.5%,and significantly reduced transpiration rate by 14.1%.Humidification treatment optimizes the growth state of tomato,and the relative growth rate shows a trend of first increasing and then decreasing during the whole growth period.Compared with the control treatment,the humidification treatment significantly increased the relative growth rate of tomatoes during the whole growth period by16.7%,and significantly shortened the whole growth period of tomatoes by about 15days.Under humidification treatment,tomato fruit yield increased by 10.7%,and yield-water use efficiency increased by 39.7%.Therefore,proper humidification in summer can change the indoor atmospheric dry environment,optimize crop growth,improve photosynthetic characteristics and water transport status,thereby increasing tomato yield and water use efficiency.3.Heating and dehumidifying system in the greenhouse in winter can significantly alter the air humidity of the tomato canopy,optimize the gas exchange rate of the leaves,and then improve the photosynthesis of the tomato leaves.There are also different effects under different sunlight conditions.The specific performance is:strong sunlight on sunny days caused short dehumidification time,but it can also increase photosynthesis to 22.3μmol m^-2 s^-1.In cloudy days,the sunlight is weak,and the air humidity in the greenhouse has been maintained at 85%.Dehumidification treatment can significantly reduce the air humidity to 40%,and the photosynthetic rate increases by 45.6%compared with the control.In addition,the microstructure of the leaves was collected and found that the increase in stomata density,duct area and number of tomatoes under dehumidification treatment provided structural support for the efficient water vapor exchange of the leaves,and preliminary proved the structural adaptability of air humidity to regulate the water productivity of tomato leaves in winter greenhouses.At the same time,it provides a new solution for the management of the air humidity in the greenhouse in winter.