Effects Of Different Irrigation Quantity On Photosynthetic Characteristics,Yield And Quality Of Netted Melon Cultivated In Substrate

Netted Melon is a water sensitive melon crop.Water management is one of the key technical links in the production of Netted Melon.Scientific and reasonable water and fertilizer management can effectively promote plant growth and development,improve plant photosynthesis,and improve fruit yield and quality.In this experiment,the coarse net type reticulated Netted Melon Variety"White Lover"was used as the test material.Four treatments were set up,including supplementary irrigation according to 120%,100%,80%and 60%of the daily transpiration evaporation（I1 treatment,I2 treatment,I3 treatment and I4 treatment）.Under the condition of pot culture,the effects of different irrigation rates on the plant growth and Photosynthetic characteristics and yield and quality,in order to explore a suitable water management model of Netted Melon.The results show that:1.The results of irrigation test in the early stage of vine extension show that:the stem diameter,fresh weight and dry weight of the aboveground and underground parts of the plants were the largest in the treatment of supplementary irrigation with 100%daily transpiration evaporation.the root shoot ratio,total dry matter content and strong seedling index were the largest,the dry matter distribution coefficient was the largest,and the plant was the most robust;The relative permeability of leaf cell membrane was significantly lower than that of the other three treatments.The net photosynthetic rate,stomatal conductance and transpiration rate were the largest,and the photosynthetic capacity was strong.2.The results of irrigation test in the middle and late stage of vine extension show that:the plant height,stem diameter,leaf number and leaf area of the plants treated with 80%daily transpiration and supplementary irrigation were significantly higher than those of other treatments,and the leaf extension rate was the fastest.The net photosynthetic rate and transpiration rate of plant leaves treated with supplementary irrigation at 100%daily transpiration evaporation are the highest,followed by the treatment with supplementary irrigation at 80%daily transpiration evaporation.The stomatal conductance（Gs）and intercellular CO₂ concentration（Ci）of the leaves of plants treated with supplemental irrigation at 80%daily transpiration were significantly higher than those of other treatments.The photochemical quenching coefficient（q P）and non-photochemical quenching coefficient（NPQ）of the treatments supplemented with 100%and 80%daily transpiration are significantly higher than those of the treatments supplemented with 60%daily transpiration.3.The results of irrigation test in the early stage of fruit development show that:the fruit-setting rate of plants treated with supplementary irrigation with80%daily transpiration is the highest,and the average length of lateral vines and the length of lateral vines with remaining melons are significantly larger than those treated with supplementary irrigation with 60%daily transpiration.The longitudinal diameter,transverse diameter and single fruit weight of the fruit treated by supplementary irrigation with 100%daily transpiration were the highest,which were significantly higher than those treated by supplementary irrigation with 60%daily transpiration,and the fruit expansion rate was the fastest.The net photosynthetic rate（Pn）,stomatal conductance（Gs）and transpiration rate（Tr）of the plants treated with supplementary irrigation at100%daily transpiration evaporation are the highest,the intercellular CO₂concentration（Ci）is the lowest,and the photosynthetic capacity is strong.4.The results of irrigation test in the middle and late stage of fruit development show that:the fruit shape index of Netted Melon treated by supplementary irrigation with 100%daily transpiration is close to 100%,and the reticulate distribution is uniform,with the reticulate density of more than 50meshes per 9 cm²,the thickness of reticulate bulge reaching 0.96 mm,and the reticulate classification is grade 5 fruit.The total yield was the largest,and the average single fruit weight was significantly higher than other treatments.The TPA hardness,elasticity,adhesiveness,chewiness and flesh hardness of fruit were significantly lower than those of other treatments.And the content of vitamin C and soluble protein in fruit are the highest.