Effects Of Nitrogen Supply On Growth And Decline Of Potato Tubers

Nitrogen significantly affects potato growth and development.There are many reports on the effect of nitrogen on potato development.However,there are few reports on the effect of nitrogen on the number of potato tubers.Tuber number as an important yield components and propagation material cannot be ignored.Therefore,in this experiment,potato Favourite was used as the research material.Through two years of field experiments combine with tuber histological observation,the changes in tuber number and tuber tissue structure in response to nitrogen supply were studied.Meanwhile,potato plant biomass,carbon,nitrogen content and other index been monitored to explain the reason for increase and decrease of potato tuber.Research indicates that:1.Potato tubers have demise phenomenon,which mainly manifests as tubers with a diameter of less than 1 cm will rot and fall during the period of tuber formation to the tuber expansion,with an average of 1.58 pcs to 3.18 pcs per plant will demise.2.Tuber demise will be affected by nitrogen supply.Insufficient nitrogen supply will exacerbate potato tuber demise.Adequate nitrogen supply can effectively reduce tuber demise proportion of tuber group level and individual plant level.3.Tuber growth or demise is closely related to plant total carbon and total nitrogen supply.After the tuber formation period,the total carbon concentration of tubers with a diameter of more than 1 cm gradually increased,while the total carbon concentration of tubers with a diameter of less than 1 cm gradually decreased,but the nitrogen supply can delay the increase tread;the total carbon,total nitrogen,and C/N in the demise tubers were significantly lower than normal tubers of the same size in the same period.So,the lower source-sink ratio(Leaf area per plant/Dry weight of reserve)of plants,nitrogen topdressing is benefit to increase the weight of total carbon and total nitrogen in potato tubers,however potato C/N although decreased rapidly during tuber formation,which may be the cause of tuber demise.