| Sweet potatoes,especially orange ones,is rich in carotenoids and other nutrients,which can be used as an important crop to solve "hidden hunger" around the world.To improve iron and zinc content in sweet potato,field experiments on foliar iron and zinc fertilizers were conducted in 2015-2016 at Panzhai Village,Lanxi City,Zhejiang Province.The experiment was investigated by split plot design using the variety of Xuyu34 and Xuzi6,which focused the effect of amino acid chelated iron zinc fertilizer and the ordinary iron zinc fertilizer on iron and zinc concentration and other nutrients in tubers.One more study was designed to compare different single amino acid chelated iron zinc fertilizers.In 2017 a greenhouse experiment was aranged to investigate the effect of different forms of iron fertilizers on remission of iron deficiency sweetpotato leaves(Xuzi6 and 8),FCR activity and mineral concentration in leaves and roots.The results showed that:1.Under field condition,foliar application of amino acid chelated iron and zinc fertilizer increaseed the yield of sweet potato and iron,zinc,calcium and magnesium content in tubers.The field experiment showed that the sweet potato yield increased by about 15%under the treatment of mixed amino acid chelated iron zinc fertilizer,which was significantly higher than that of CK.Iron and zinc concentrations of Xuyu34 increased by 112.5%,81.3%,and Xuzi6 increased by 71.4%and 41.2%in the tubers.2.In the field,effect of single amino acids chelated iron and zinc fertilizers on yield was not significant,but significant effects on flavonoids,total soluble sugar and crude protein content,iron,zinc,calcium and magnesium content in the tuber.Glu chelated iron and zinc fertilizer had a positive impact on the total flavonoids content of tuber,stem and leaf.For nutrient concentration,treatment of Gly chelated iron zinc fertilizer Xuyu34 had the maximum iron concentration of 106 mg kg-1,and the maximum value of 21.3 mg·kg-1 zinc in mixed amino acids chelated iron zinc fertilizer;Xuzi 6 had a maximum value of 76.9 mg kg-1 iron in Met chelated iron and zinc fertilizer;the maximum value of 17.9 mg kg-1 zinc in Glu chelated iron zinc fertilizer.3.Pot experiment suggested different iron fertilizers increaseed the iron content of sweet potato tuber,but difference was not significant.Shoot and root biomass of sweet potato were not significantly different among treatments.At the same time,foliar iron fertilizers reduced other mineral elements in root tuber of sweet potato,including most essential elements and heavy metal elements.4.It suggested that different forms of iron fertilizer significantly affected leaf and root ferric chelate reductase(FCR).Average FCR activity of leaf and root in Xuzi6 was higher than Xuzi 8;under Fe2(SO4)3 treatment,leaf FCR activity had the highest value,which need 1h for Xuzi8 and one day for Xuzi6.For root FCR activity,Xuzi8 had the highest value in EDTAFe(?)treatment(third days),but Xuzi6 have the same root FCR value under iron sufficient conditions.5.Different forms of iron affected the rate of leaf absorption of iron.For Xuzi8 leaf iron penetration rate reached a maximum value of 541.8 mg·kg-1 on the first day under FeSO4 treatment;and a maximum of 523.9 mg·kg-1 in third day under Fe2(SO4)3 treatment.There were no significant differences between two treatments.While for EDTAFe(?)a maximum value of 239 mg·kg-1 accured on the first day,but no significant difference with that of the first hour.The rate of iron absorption of Xuzi6 was higher than that of Xuzi8,and the absorption rate of Fe undere Fe2(SO4)3 was higher than that under FeSO4,but that change with time was the same,which all had the highest 1439 mg·kg-1 and 1410 mg·kg-1 on the fifth day. |
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