| In order to explore the effects of different concentrations of brackish water and alternate irrigation in root zones on photosynthetic characteristics,stress resistance,quality flavor and yield of facility tomato during production,and to provide theoretical basis for high-quality production of facility tomato in brackish water resources rich areas.With large fruit tomato ’TY1602’ as the material,substrate tank culture was adopted,and root box was used to divide the irrigation environment into left and right sides,namely,L side and R side.Under such conditions,fresh water,brackish water with EC of 2.5,3.3 and 4.1mS/cm were used for irrigation,and the upper and lower limits of the maximum water capacity between two kinds of fields were set,which A[L side(65%-90%),R side(35-50)%]and B[L side(55-80)%,R side(25-40)%],automatic drip irrigation was lower than the lower limit,and drip irrigation was stopped when the upper limit was reached.A total of 9 treatments,CK:fresh water,L(65-90)%,R(65-90)%;T1:fresh water,A;T2:fresh water,B;T3:2.5mS/cm,A;T4:2.5mS/cm,B;T5:3.3mS/cm,A;T6:3.3mS/cm,B;T7:4.1mS/cm,A;T8:4.1mS/cm,B.The effects of different treatments on photosynthetic characteristics,stress resistance,flavor quality,growth and development of tomato were analyzed.The results show that:(1)Under brackish water deficit irrigation with low concentration,the photosynthetic index and carbon assimilation enzyme activity of leaves were increased,and the Pn value of T6 treatment in spring and T7 treatment in autumn was the highest,which was 29%-55%higher than that of the control.The increase of soluble protein,proline(Pro),malondialdehyde(MDA),peroxidase(POD),catalase(CAT),abscisic acid(ABA),ethylene(ETH),cytokinin(CTK)and other stress-related substances gradually increased with the increase of stress degree.The safe growth and development of plants were ensured by osmotic regulation,hormone regulation and peroxide removal.(2)The zonal deficit irrigation on both sides of the root system greatly stimulated the growth and development of plant roots,and the volume,surface area and number of root tips increased significantly.In spring and autumn,the root vitality of T2 treatment was the highest,and the root characteristic value of L side was better than that of R side,although brackish water irrigation was not conducive to the absorption and utilization of plant nutrients and water.However,fully developed roots could absorb water to the maximum extent,and the water utilization rate was significantly increased compared with the control.In spring and autumn,T6 treatment significantly increased by 105%and 334%compared with the control,showing obvious water-saving benefits.Compared with the control,the biomass and nutrient elements of the whole plant increased to a certain extent.The biomass of T5 treatment in spring and T1 treatment in autumn was increased by 140.7%and 115.1%,respectively.(3)From the perspective of fruit quality and flavor,both brackish water and water deficit irrigation could significantly improve fruit quality,and with the change of treatment,Vc,soluble solid,soluble sugar,organic acid,glucose,fructose,sucrose,etc.,increased,and the Vc content of T8 treatment was the highest in spring and autumn.In spring stubble,the soluble sugar content of T8 treatment increased by 143.7%,that of T7 treatment increased by 172.9%,and that of T5 treatment was the highest,which increased by 13%compared with CK.The content of volatile substances reached the maximum under T6 treatment,which increased by 166%.Corresponding to the fruit quality and flavor,the yield of spring stubble was significantly lower than that of the control when EC=4.1mS/cm,while that of autumn stubble was significantly lower when EC=2.5mS/cm.However,in spring and autumn,the yield of T1 treatment was higher than that of the control.By combining the scores of the two stubble,the growth status of the two stubble was inconsistent under the upper and lower ranges of brash water and alternate irrigation in the root zone of different concentrations.In autumn stubble,T5 treatment[EC=3.3mS/cm,L side(65-90)%,R side(35-50)%]had the highest score,while in spring stubble,T6 treatment[EC=3.3mS/cm,L side(55-80)%,R side(25-40)%]had the highest score,which indicated that brackish water irrigation could effectively improve tomato quality and flavor,and deficit irrigation within a reasonable range could ensure the normal growth and development of plants,which had obvious water-saving benefits.For actual production,brackish water with EC=3.3mS/cm can be used for irrigation in areas with abundant brackish water resources and shortage of fresh water resources.At the same time,appropriate irrigation upper and lower limits can be selected according to different cultivation seasons as irrigation strategies for high-quality tomato production,so as to save water resources,improve water-saving efficiency and improve tomato flavor quality. |
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