The Mitigation Effects Of Exogenous Dopamine Pretreatment On Continuous Cropping Obstacles In Watermelon

Continuous cropping obstacles refer to the fact that when the same plot or the same crop or similar crops are continuously planted on the same field,the plant growth will continue to weaken and the economic product output and quality will decline under the conditions of reasonable production management and strict cultivation mode.The continuous cropping obstacles of watermelon in melon crops are the most serious.Continuous cropping obstacle can easily lead to deterioration of the physicochemical properties of soil,resulting in the degradation of the production capacity of the field,increase the content of harmful bacteria in the soil,and watermelons are the extreme vulnerability during growth.In particular,a large number of damping off occur after planting and blights that occur after flowering will directly lead to a decline in the yield of watermelons and even the outbreak of production.Dopamine(DA)is a kind of catecholamine that enhances the plant’s ability to resist stress.There are currently few reports on Dopamine’s ability to relieve the obstacle to continuous cropping.In this experiment,the main vegetable crop,the watermelon(Citrullus lanatus(Thunb)Matsum & Nakai),was studied.The experiment use the anti-fusarium material "Jingxin No.2" and the non-resistant wilt disease material "Qianding No.1".Materials use the potted methods were used to study the effects of dopamine solution pretreatment of the watermelon growth under continuous cropping obstacles.The study result shows as:1,Dopamine solution pretreatment significantly increased the plant height,stem diameter,leaf size,number of leaves and dry and fresh matter quality of watermelon under continuous cropping obstacles.It also increased the robust index of watermelon plants,prolonged the flowering period of watermelon,and affected the female flowers of watermelon,and ensured the growth of the watermelon.2.Dopamine solution pretreatment significantly increased the Specific leaf weight,chlorophyll content and net photosynthetic rate of watermelon leaves under continuous cropping obstacles,effectively improved the photosynthesis of watermelon under continuous cropping obstacles,and improved the watermelon’s autotrophic abilities.3,Dopamine solution pretreatment significantly improved the activity of the antioxidant enzyme system,including superoxide dismutase(SOD),polyphenol oxidase(PPO),catalase(CAT),peroxidase(POD),ascorbate peroxidase(APX).Dopamine solution pretreatment significantly reduced the intracellular malondialdehyde content(MDA)produced by oxidative decomposition and significantly reduced REL.Dopamine solution pretreatment also significantly improved the antioxidant capacity of the plant cells,enhances the resistance to continuous cropping obstacles.4,The pretreatment of dopamine solution significantly increased the watermelon root activity in plant roots and content of Prolinein plant leaves under continuous cropping obstacles.The pretreatment of dopamine alleviated the damage of continuous cropping obstacles to watermelon plants,and ensured the growth and development of watermelon.5,Dopamine solution pretreatment significantly increased nitrogen metabolism enzymes System activity.The nitrogen metabolism enzymes system includes nitrate reductase(NR),glutamine synthetase(GS),glutamate synthase(GOGAT)and glutamate dehydrogenase(GDH).Dopamine solution pretreatment also increased the nitrogen assimilation of watermelon plants,which in turn promoted the nitrogen metabolism of watermelon.6,Dopamine solution pretreatment increased the fruit weight of watermelon,increased the protein content in the fruit,reduce soluble sugar content and influenced the nutritional level of watermelon.7,Pretreatment with dopamine solution reduced the incidence of blight and cataplexy disease in watermelon.