Effects Of Brackish Water Irrigation On Soil And Plant Mineral Elements And Sucrose Metabolism Of Tomato In Solar Greenhouse At Different Growth Stages

In order to rationally utilize the unique resources such as brackish water resources and sandy soil in Northwest China,and promote the efficient and sustainable development of tomato facilities,this study used different brackish water irrigation methods:CK:brackish water direct irrigation,T1:freshwater direct irrigation,T2:mixed water irrigation(brackish water:freshwater = 1:1),T3:brackish water and fresh water in rounds of fertility(direct irrigation with fresh water during seedling stage and flowering period,direct irrigation with brackish water during fruit development period),T4:brackish water and freshwater per cycle to clarify the content of mineral elements,the sucrose metabolism of tomatoes in solar greenhouse,and the influence of the transport direction of photosynthetic products of plants,which can provide a theoretical basis for exploring the physiological mechanism of the impact of brackish water on the quality of tomato fruits.The main findings are as follows:1.Effect of different saline water irrigation on the content of mineral elements in roots,stems,leaves and fruits of tomato plantsThe content of N,K,Na and Mg in tomato fruits were higher than that in autumn cultivation season,and the content of P and Ca in spring cultivation season were lower than that in autumn.Under the condition of brackish water,the accumulation of total N and total Na in tomato plants increased from fruit setting stage to late fruiting stage.The increase in total Na total N and total Mg accumulation was the largest under CK,but it is not conducive to the absorption and utilization of trace elements in fruits.The T4 are beneficial to the accumulation of P in tomato plants during fruit set and full fruit period,and T3 increase the absorption of Mg in tomato fruits.The T1 treatment had higher total K content in all parts of the four growth stages,It also promoted N,P,K,and Ca absorption and accumulation of tomato fruit in color conversion period and mature period.2.Effects on soil nutrient and ionic content of tomato plant root zone of brackish water under different irrigation methods2.1 Compared with freshwater irrigation,the brackish water with different irrigation methods can increase the total salt?ionic and total phosphorus content to varying degrees.In the late fruit stage,the salt content of CK is the highest.At the seedling stage and fruit setting stage,the total phosphorus content increased most with T2 treatment,followed by T3 treatment;At the fruit setting stage,T1 treatment was beneficial to Phosphorus accumulates in soil;At late fruiting stage brackish water irrigation can increase content of available potassium in soil.During fruit and late fruiting period,T2 treatment significantly increased the content of Na+ slightly,T4 significantly increased the content of K+ in later fruit stage,T3 significantly increased the content of HC03-and S042-in late fruiting stage.2.2 Brackish water irrigation is not conducive to the accumulation of Cu ions in soil,but brackish water irrigation is beneficial to increase the accumulation of Fe ions and Mn ions in the rhizosphere soil of full fruit period.T2 and T4 treatments increase the maximum.T3 is beneficial to improve the accumulation of Zn ions in the soil.3.Changes of sugar content and enzyme activity in tomato fruits under different irrigation conditions with brackish waterDifferent irrigation methods had different contents of sugar in tomato fruits.The content of soluble sugar in fruits under CK was the highest,and the content of starch in T1 was the highest.Compared with freshwater irrigation,CK had the highest activity of invertase,and the activity of enzyme under T4 was lower than that of CK.The activity of SS enzyme gradually decreased with the development and maturation of the fruit,and the brackish water irrigation was higher than the freshwater irrigation,and the activity of enzyme under CK was still the highest.The activity of the SPS enzyme did not change much during different growth periods,but it was still slightly salty water treatment higher than the fresh water treatment.4.Changes of transport direction of photosynthetic products of tomato under different irrigation conditions with brackish water4.1 Different irrigation methods of brackish water had different effects on the photosynthesis and photosynthate distribution of tomato.The photosynthetic capacity of the CK was the lowest,and the S13C on feeding leaves was also the lowest.The ?13C value of the fedding leaves under T4 was the highest,followed by freshwater irrigation.T4 were the most capable of transporting photosynthetic products to the below leaf,followed by T1.T2 irrigation had the strongest ability to transportphotosynthetic products to the root which resulted in the lowest ?13C value of the lower position fruit.4.2 Brackish water irrigationreduced the photosynthetic capacity of tomato so that the total biomass of tomato under brackish water treatment was lower than freshwater irrigation treatment.The decrease in the net photosynthetic rate of T4 was the lowest.Therefore,the biomass allocation ratio of tomato fruits under T4 was the highest,and T3 was the second.Compared to other trentments,the biomass of tomato more allocated in roots,stems and leaves of under T2,but the fruit biomass under this treatment was the lowest.