| The vegetable industry is an important pillar of China's agricultural and rural economic development,and tomato is one of the most consumed vegetables.For a long time,farmers have been blindly and unevenly fertilising in pursuit of high yields,which not only causes soil disorders,but also affects the growth of tomatoes,resulting in reduced quality and yield.As a common nano-material,Zn O nanoparticles have shown a certain promotion effect on crop growth and development.In this paper,the effects of water-soluble fertilizer containing different concentrations of Zn O nanoparticles on tomato drought resistance and fruit quality were investigated,and the role of Zn O in improving tomato drought resistance and fruit quality was explored,which provided a theoretical basis for tomato normal growth and improving fruit quality under adverse conditions.The experiment was carried out in greenhouses by quantitative irrigation method.The concentration of Zn O nanoparticles was set as 0(CK),60,80,120,160 and 200 mg·kg-1respectively.The irrigation amount was divided into normal and 60%irrigation for the whole reproductive period.The following conclusions were drawn from the study.(1)Under normal irrigation conditions,the low concentration Zn O nanoparticles(60and 80 mg·kg-1)treatments increased the height and dry matter accumulation of tomato plants,and also significantly increased soil urease and catalase activities.At 30 days,the catalase activity in the soil treated with 60 mg·kg-1Zn O increased by 10.17%compared to the control.In contrast,the high concentration of Zn O nanoparticles(200 mg·kg-1)significantly inhibited tomato plant height and dry matter accumulation,thus suppressing the growth and development of tomato plants.(2)Under normal irrigation conditions,60 and 80 mg·kg-1Zn O treatments reduced the malondialdehyde(MDA)content of tomato leaves and increased the growth of antioxidant enzymes such as lipoxygenase(LOX),peroxidase(POD),catalase(CAT),superoxide dismutase(SOD),ascorbate peroxidase(APX),polyphenol oxidase(PPO)and Glutathione reductase(GR)activity,reducing the accumulation of reactive oxygen species in tomato leaves,thus reducing oxidative damage during the reproductive period and promoting tomato growth and development.In contrast,high concentrations of Zn O,especially 200mg·kg-1,significantly increased the MDA content of leaves,reduced the activities of POD,CAT,APX and other antioxidant enzymes,and decreased the antioxidant capacity of tomato leaves.(3)Under normal irrigation conditions,low concentration treatments of Zn O at 60 and80 mg·kg-1significantly improved the fruit setting habits of tomato plants,such as flowering number,fruit setting number,fruit setting percentage and single fruit weight.The hardness and the vitamin C content of tomato fruit were also increased by low concentration Zn O.In addition,low concentration Zn O treatments reduced the content of MDA in tomato fruit and increased the activities of SOD and POD,so as to enhance the antioxidant capacity of fruit and improve the quality of fruit.(4)Under the condition of 60%irrigation,tomato plant height growth and dry matter accumulation were affected,and the content of MDA in tomato leaves increased,resulting in oxidative damage to tomato leaves.The application of low concentrations Zn O nanoparticles(60 and 80 mg·kg-1)reduced the oxidative damage caused by water deficiency and reduced the MDA content,while increasing the activity of antioxidant enzymes,thus improving the drought resistance of tomato plants and promoting the growth and dry matter accumulation of tomato plants. |
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