The Effects Of HIDS On The Growth And Development Of Hydroponic Summer Squash

To explore the effects of the L-Aspartic Acid derivative,urea disuccinic acid(HIDS),on reducing fertilizer and increasing yield in agricultural production.In this experiment,the ‘Nongyuan No.1’ summer squash was used as the material for hydroponic culture.The basic nutrient solution used Yamazaki cucumber formula.Seven nutrient solution treatments were set up,CK was treated with conventional nutrient solution(At seedling stage,the nutrient solution was 1/2 times and changed every 6 days,at vine-pulling stage and flowering stage,the nutrient solution was 1 times and changed every 6 days,and at fruit stage,the nutrient solution was 1 times and changed every 3 days);T1 was low concentration nutrient solution treatment(The nutrient solution was 1/3 times in seedling stage,5/6 times in vine-pulling stage,flowering stage and fruiting stage.The replacement time of nutrient solution was the same as that of CK);T2,T3,T4,T5 and T6 treatments added 7,35,70,105,140 mg HIDS per liter of nutrient solution on the basis of T1 treatment.The concentrations of HIDS in the nutrient solution were 7,35,70,105 and 140mg·L-1.The effects of HIDS on growth,physiology,mineral element absorption,photosynthetic and fluorescence characteristics,leaf structure,yield and quality of summer squash were studied.The effects of HIDS on the growth and development of summer squash cultivated in low concentration nutrient solution and the suitable dosage of HIDS in water culture were discussed to provide theoretical basis for the application of HIDS as nutrient solution enhancer in agriculture.The main results are as follows:1.The plant height,stem thickness,leaf area,and dry and fresh weight of summer squash treated with T1 were lower than that of treated CK,and the dry weight and fresh weight of treated CK were reduced by13.54% and 13.39%,respectively.The addition of HIDS to the nutrient solution can promote the growth and dry matter accumulation of summer squash,but the addition of HIDS has different effects on summer squash.When the HIDS concentration in the nutrient solution was 70 mg·L-1,the growth of summer squash was the best,and the dry and fresh weight of the whole plant were significantly increased by 16.15%,17.17%,and higher than the treatment of CK.2.Compared with the treatment of CK,the soluble sugar,reducing sugar,starch,soluble protein,free amino acid content and antioxidant enzyme activity of T1 summer squash leaves were reduced,hydrogen peroxide and superoxide anion free radicals accumulated membrane peroxidation,and MDA increased.When the HIDS concentration in the nutrient solution is 70 mg·L-1,it can effectively alleviate the effects of low-concentration nutrient solution on the sugar,protein,free amino acid and antioxidant system of ummer squash leaves,and improve the resistance of summer squash.3.When the HIDS concentration in the nutrient solution is 70 mg·L-1,it can increase the content of mineral elements in the leaves of hydroponic summer squash,increase the chlorophyll content of the leaves,and increase Pn,Tr,Ci,Gs,Fv/Fm、Fv′/Fm′、ETR、q P and other photosynthetic fluorescence parameters,reduced NPQ.4.Observation of the anatomical structure of the leaves found that reducing the concentration of nutrient solution mainly affects the growth of the upper epidermis of the summer squash and the cell density of the fence tissue,but has no significant effect on the thickness of the fence tissue and sponge tissue.When the HIDS concentration in the nutrient solution is 70 mg·L-1,it can significantly alleviate the damage of the low-concentration nutrient solution to the upper epidermis.Although the leaf thickness and fence tissue thickness do not reach the conventional nutrient solution cultivation effect,the fence tissue density increases significantly.It is more conducive to the capture and utilization of light energy by summer squash leaves.5.When the HIDS concentration in the nutrient solution was 70 mg·L-1,the yield per plant and the soluble sugar,Vc,and soluble protein in the fruit of summer squash were 31.76%,22.00%,40.21%,11.97%higher than that of treatment T1,and higher than treatment CK.In addition,when the concentration of HIDS was 70 mg·L-1,the nutrient solution cost was lower than that of CK.In conclusion,when the concentration of HIDS is 70 mg·L-1,the cost of nutrient solution can be reduced,the yield and quality of summer squash can be improved,the photosynthetic capacity of summer squash and the absorption and utilization of mineral elements can be enhanced,and the utilization rate of nutrient solution can be improved.