Effects Of Different Planting Densities And Number Of Functional Leaves On Photo Synthetic Characteristics And Yield And Quality Of Muskmelon In Greenhouse

Muskmelon(Cucumis melo L.),one of the top ten fruits in the world,has become one of the important cash crops in Ningxia in recent years with its growing area continuously expanding.To study the effects of interaction of density and functional leaves on canopy photosynthetic characteristics,yield and quality of muskmelon.In this study,’Gailiangxizhoumi 25’ of thick-crusted melon was used as experimental material to conduct field experiments under different planting densities and the number of functional leaves.Three density gradients were set:2000 plants/667 m2,2200 plants/667 m2 and 2400 plants/667 m2,with three functional leaf gradients:25 leaf,and leaf,leaf,and two factor interactions,a total of nine,two crop planting in the spring and autumn,the determination of growth potential,canopy characteristics,plant photosynthetic index,quality index and yield,combined with analysis of variance and principal component analysis,clear the optimal cultivation of ningxia thick skin melon leaf number,planting density and function for ningxia to grow thick skin melon provide theoretical basis for high yield and good quality.The main research results are as follows:(1)The plant height and leaf area of spring stubble increased gradually with the increase of planting density,but when the planting density was 2400 plants/667 m2(A3),the lower canopy shade was serious,which was not conducive to reproductive growth.With the increase of planting density,the leaf area increased first and then decreased,and the plant height decreased gradually.In terms of plant growth potential,the planting density of 2200 plants/667 m2(A2)in spring and autumn was more suitable for planting thick-skinned melon in the field.(2)The order of chlorophyll size in the upper,middle and lower canopy of spring stubble and autumn stubble was middle>upper>lower canopy.The leaf area index of plant population fluctuated between 2.83 and 3.59.The number of functional leaves was the main factor affecting leaf area index,and planting density was the secondary factor.A2B3 treatment had a higher leaf area index,which could not only maintain a higher light interception rate and promote robust plant growth,but also avoid the canopy closure caused by low light transmittance and reduce light energy conversion efficiency.Therefore,the structure distribution within the plant population was reasonable.(3)When the density is fixed,the net photosynthetic rate of spring stubble melon leaves gradually increases with the increase of the number of functional leaves.A2B3 stabilized the transpiration rate,intercellular CO2 concentration,and stomatal conductance of melon plants at the same level as the control,and the net photosynthetic rate was slightly higher than that of the control.In addition to increasing the transpiration rate and stabilizing the net photosynthetic rate and the intercellular CO2 concentration maintained at the same level in the control,the A3B1,A2B2 and A2B3 treatments of autumn stubble also improved the stomatal conductance of the plants.(4)There was no significant difference between the soluble solids content of the spring stubble and autumn stubble treatment centers compared with the control,but the soluble solids content in the spring stubble center fluctuated between 18.95-19.43,and the autumn stubble was between 16.13-13.33,and the quality of autumn stubble fruit decreased significantly compared with that of spring stubble.The A2B3 treatment of spring and autumn stubble significantly increased the soluble solids content,soluble protein content,vitamin C content,sucrose content and fructose content at the edge of melon fruit,which was the best treatment.(5)The single fruit weight of spring and autumn stubble decreased with the increase of density and functional leaf.The plot yield and 667 m2 yield of spring stubble increased first and then decreased with the increase of density and functional leaves.The plot yield and 667 m2 yield of A2B3 treatment were the highest and 667 m2 yield was 6579.92 kg/667 m2.The plot yield and 667 m2 yield of autumn stubble A3B2 treatment were the highest.Up to 4284.55 kg/667 m2,the plot yield and 667 m2 yield of A2B3 and A3B1 treatments were slightly lower than those of A3B2 treatments,with no significant difference.Fruit weight per fruit and maximum yield of 667 m2 in autumn stubble were significantly decreased by 0.97 kg and 2295.37 kg,respectively,compared with spring stubble.According to the data of the two crops,considering the plant growth,canopy characteristics,photosynthetic characteristics,fruit quality and yield,the optimal treatment was 2200 plants/667 m2 and 29 functional leaves(A2B3).This cropping management model is recommended under similar climatic conditions to this study.