| Potato(Solanum tuberosum L.)is the world’s fourth largest food crop.In 2015,China officially launched the potato main food strategy,the core of which is to improve the yield level and nutritional quality of potato per unit area.In the field of current agricultural production,in view of the problem of zinc deficiency in farmland soil is widespread,increasing zinc fertilizer is one of the important measures to promote crop yield and quality,and has achieved good results in rice,wheat,corn and other crops.Under the background of potato main diet,it is important to explore the influence of exogenous zinc on the growth and development of potato and the zinc nutrition of tuber.In this study,with potato as the test materials,the effects of zinc on the growth and development of potato and its physiological effects,the effects of exogenous zinc on the absorption and distribution of potato zinc and the nutritional quality of potato tubers,the effects of different zinc application methods and zinc sources on the yield of potato tubers,the content of zinc and the bioavailability of zinc were studied by nutrient solution culture,pot culture and field experiment.The aim is to provide theoretical guidance for scientific planning of zinc fertilizer,promoting potato yield and quality,and realizing potato tuber rich in zinc.The main results of the study are as follows:1.Zinc deficiency leads to the stunted growth and development of potato.Potato virus-free tissue culture seedlings treated in zinc deficient nutrient solution(0 μmol/L ZnSO4·7H2O)for 14 days showed poor root elongation and growth,and the total root length,root surface area and root activity decreased significantly.In the treatment of zinc deficiency for 46 days,the symptoms of small leaves,loss of greenness and yellowing,and cluster of apical leaflets appeared in the aboveground,the functional leaf area and total chlorophyll content were significantly reduced,and the photosynthetic rate was significantly decreased.The zinc content in the upper and lower leaves increased by 35.16% and 53.77%,respectively,but potatoes did not return to normal growth.2.Zinc deficiency reduced the scavenging ability of reactive oxygen species in potato,aggravated the degree of cell membrane lipid peroxidation,and abnormal carbon and nitrogen metabolism.The activities of superoxide dismutase(SOD)and peroxidase(POD)were significantly decreased,the contents of malondialdehyde(MDA),free proline(Pro)and free amino acid were significantly increased,and the contents of soluble sugar,total nitrogen and soluble protein were significantly decreased.3.Under different zinc application methods,exogenous zinc(ZnSO4·7H2O)can promote dry matter accumulation,improve tuber nutritional quality,and significantly increase zinc content and bioavailability of zinc in different potato varieties.The total zinc utilization rate of leaf zinc application was 9.65～24.71 times that of soil zinc application.Soil zinc application increased the zinc content of potato tubers by0.77～9.63 mg/kg,with an average increase of 29.95%,and the total zinc accumulation of potato tubers increased by 61.37%.Leaf zinc application increased the content of zinc in tubers by 3.34～11.57 mg/kg,with an average increase of 63.26%,and the total zinc accumulation in plants increased by 151.04% on average.The molar ratio of phytic acid to zinc in potato tubers decreased by 38.89%～51.20% and 27.65%～43.26% after leaf zinc application compared with no zinc application and soil zinc application.4.Spraying different zinc sources on the leaves significantly increased the zinc content of potato and improved the physiological condition of potato in the field.The increase of zinc content in tubers treated with organic zinc chelate fertilizer was higher than that treated with inorganic zinc fertilizer.Zinc sulfate(ZnSO4),zinc citrate(CAZn),zinc proline(PRO-Zn)and zinc chitosan oligosaccharide(COS-Zn)treatments decreased the relative electrical conductivity of potato leaves,significantly decreased the contents of malonaldehyde(MDA)and free proline(PRO),and significantly increased the content of soluble protein.The increase of zinc concentration in stems,leaves,roots and tubers treated with CA-Zn,Pro-Zn and Cos-Zn was higher than that treated with ZnSO4.After harvest,the concentration of zinc in CA-Zn treatment was17.06 mg/kg,which was 8.53% higher than that in ZnSO4 treatment,and the difference was significant.The concentrations of zinc in the PRO-Zn and COS-Zn tubers were16.13 mg/kg and 16.44 mg/kg,which were 2.61% and 4.58% higher than those in the ZnSO4 treatment,respectively,and the difference was not significant.5.Under the treatment of exogenous zinc application,the yield and zinc content of the 10 potato cultivars were significantly different.Soil zinc application and leaf zinc application increased potato yield by 7.20% and 6.52%,respectively,among which Huashu3 had the highest yield increase under different zinc application methods.Without zinc fertilizer,the content of zinc in potato tubers ranged from 9.12 mg/kg to15.71 mg/kg.Under the condition of soil zinc application,the zinc content of each variety increased to 9.89 mg/kg～20.35 mg/kg,and the variation coefficient ranged from0.60% to 6.10%,among which,the zinc content of Huashu 9 was the highest,and that of 08CA-9635-19 was the lowest.Under the condition of leaf zinc application,the variation of zinc content increased to 16.20 mg/kg～24.68 mg/kg,and the variation coefficient ranged from 1.83% to 5.29%,among which the highest zinc content was found in Shepody and the lowest in Atlantic. |
PDF Full Text Request