Effect Of Iron Application On Mineral Nutrition And Berry Composition Of Wine Grape

The availability of iron in alkaline calcareous soils in the wine-producing area at the eastern foot of Helan Mountain in Ningxia is poor.The low temperature in spring reduces the mobility of iron,which comprehensively triggers iron-deficiency yellowing of grapes,causing leaf chlorosis,weakening of the tree,and affecting tree development and berries quality.In order to explore the effect of exogenous iron supplementation on the physiological regulation and metabolites of wine grapes,the 8-year-old wine grape "Cabernet Sauvignon" was used as the research material,and a random block design was adopted,from the three perspectives of iron application type,iron application amount and iron application method The effects of iron application during the color transition period on the physiological activity of leaves,plant organ nutrient content,fruit quality and yield of wine grapes were comprehensively discussed,aiming to provide technical support and theoretical guidance for efficient fertilization in the production of high-quality and high-yield wine grapes.The results of the study are as follows:(1)Increased application of various iron fertilizers can significantly improve plant leaf photosynthetic parameters,leaf protective enzyme activities,plant nutrients and grape berry components.Ferric citrate and ferric iron ethylenediaminetetraacetate(EDTA-Fe)can significantly improve the photosynthetic characteristics and physiologically active components of leaves.Ferric citrate can significantly increase the phosphorus and iron content in grape plants,and effectively promote the soluble solids,tannins,and total flavonoids in grape berries.As well as the synthesis of flavan-3-ols and other components,EDTA-Fe has a significant effect on increasing nitrogen and zinc content in plant organs,and at the same time significantly increases berry phenolics.Based on the principal component analysis of 66 factors related to grape physiology and quality,the comprehensive score of iron fertilizer on wine grapes is as follows:iron citrate>EDTA-Fe>ferrous sulfate>ferrous gluconate>iron sugar alcohol.It was discovered that ferric citrate promotes the synthesis of anthocyanins and flavanone monomers in the peel.Foliar spraying with ferric citrate during the color transition period can effectively improve the growth and development of Cabernet Sauvignon and enhance the quality of berries.(2)Foliar spraying of EDTA-Fe can increase leaf chlorophyll content,enhance plant stress resistance,increase the mineral element content of grape plants,and improve the composition of grape berries.The leaf chlorophyll and net photosynthetic rate of 0.15%EDTA-Fe sprayed were increased by 24.67%and 16.31%,respectively,compared with spraying water.The fruit has the highest nitrogen,phosphorus,potassium,magnesium,iron and boron content,and the total berry The content of phenols,anthocyanins,and total flavonoids are the most abundant,reaching 14.23 mg·g-1,3.13 mg·g-1,and 6.93 mg·g-1,respectively.Through the principal component analysis of the factors related to grape physiology and berry quality,it is concluded that foliar spraying of 0.15%EDTA-Fe has the best effect on wine grape plant cultivation and fruit quality improvement.Therefore,three foliar sprays are used during the color conversion period.0.15%EDTA-Fe has the best effect.(3)Drip application and foliar application of EDTA-Fe increased leaf chlorophyll content and plant nutrients,fruit soluble solids,tannins,total phenols,anthocyanins,total flavonoids and flavan-3-ols.The combination of halved iron fertilizer spraying will significantly increase the chlorophyll content,photosynthetic rate,fruit soluble solids,tannins,total flavonoids and flavan-3-ols,but compared with foliar sprays of 0.15%EDTA-Fe,leaf physiology Activity,berry ear length,particle size and yield are reduced.Principal component analysis of grape physiology and quality showed that the combination of halving iron fertilizer and spraying drops had the highest score.Therefore,the effect of dripping 7.5 kg·hm-2 with 0.075%ferric ethylenediamine tetraacetate on leaves during the color conversion period is the best.