| Mineral elements calcium and zinc are essential elements in the process of plant growth and development,which play an important role in various physiological and biochemical processes.In order to study the effects of calcium and zinc on harding-shell development and fruit quality of walnut,walnut varieties’ Wen 185 ’and’ Xinxin 2 ’ walnut were sprayed with different concentrations of calcium and zinc chelate solution on leaves.The main results are as follows:1.Effects of spraying calcium chelate and zinc chelate on lignin synthesis of walnut.The results showed that calcium chelates diluted 1500 times significantly promoted cellulose synthesis in endocarp of ’Wen 185’walnut,while zinc ions inhibited it.At the end period of harding endocarp(June 27),the cellulose contents reached 13.95%.And as calcium chelate diluted 1500 times,it significantly increased the contents of hemicellulose and lignin contents in endocarp,reached to 18.70% and 33.84%,respectively.Among the varieties’ Xinxin 2’ walnut,1500 times liquid chelated zinc promoted the synthesis of endocarp cellulose,which was 8.19%(sampled on June 27),while calcium inhibited the synthesis of cellulose in ’Xinxin 2’walnut pericarp.Diluted 1500 times liquid chelated calcium promoted the synthesis of hemicellulose and lignin in the endocarp of ’Xinxin 2’ walnut,reaching 16.41% and 22.92%,respectively.2.The effects of spraying calcium chelate and zinc chelate on the activities of lignin-related enzymes in walnut and the contents of lignin synthesis intermediate metabolites in endocarp were studied.the results showed that the effects of different treatments on the enzyme activities of PAL,PPO,POD and CAD were different,which showed that the activities of PAL,PPO and POD decreased and the activities of CAD increased.The changes of enzyme activity caused the changes of lignin intermediate metabolites,which was consistented with the regularity of lignin synthesis.3.Spraying calcium chelate and zinc chelate can promote the fruit yield and quality of walnut ’Wen 185’and ’Xinxin 2’,which is proportional to the treatment concentration,and the effect of spraying 1500 times dilution solution of calcium chelate and zinc chelate is the most obvious.For ’Wen185’ walnut,the single fruit weight treated with calcium chelate sprayed with 1500 times dilution solution showed a very significant relationship with the control,which was 13.52 g and 0.05 times that of the control;the kernel yield of the calcium chelate solution with different dilution times showed little difference with the control,but increased by 6.59%-9.59% compared with the control;under the calcium chelate treatment,the average shell thickness was 6.34%,which was thicker than the control 0.08 mm.For variety of ’Xinxin 2’ walnut,calcium and zinc chelate treatments increased fruit weight and shell thickness compared with the control,and 1500 times treatment significantly higher than that of the control by 20.73% and 10.81%,respectively.4.The internal quality of varieties of ’Wen185’ and’ Xinxin 2 ’walnut was improved under the influence of chelated calcium and zinc,which the calcium chelate sprayed with 1500 times dilution showed the greatest effect on the contents of fat,protein and total sugar between the two walnut varieties.Under the treatment of1500 times calcium chelate,the contents of fat,protein and total sugar in walnut were 65.61%,0.82% and1.95%,respectively,which were 11.92%,28.13% and 10.80% higher than those of the control.Under this treatment,the contents of fat,protein and total sugar of ’Xinxin 2’ walnut were 59.88%,0.73% and 1.81%,respectively,which were 0.07 times,0.14 times and 0.24 times that of the control.The principal component analysis combined with the appearance and internal quality index of walnut showed that ’Wen 185’ walnut and ’Xinxin 2’ walnut could get the highest score under the treatment of calcium chelate with dilution of 1500 times.Therefore,calcium chelate with dilution of 1500 times can promote the synthesis of lignin in endocarp of walnut varieties of ’Wen 185’ and ’Xinxin 2’,accelerate fruit development,promote fruit growth,increase fruit shape and nucleolus development.It plays an important role in increasing yield and internal quality indexes such as fat,protein and total sugar,so it is recommended to spray calcium chelate with 1500 times dilution in production. |
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