The Effects Of K And Ca And Mg Applied In Foliar Nutrients On The Pericarp’s Coloring And The Discussion Of The Physiological Causes Of Litchi Chinensis Sonn. Cv Feizixiao

The growth of pericarp coloration and pulp relish of Feizixiao litchi(Litchi chinensis Sonn. cv. Feizixiao) are not synchronous, and it is of great theoretical and practical significance of research on K, Ca and Mg regulate its coloration and its mechanism. It was conducted with Feizixiao litchi fruits to study the effects of K and Ca and Mg applied in foliar nutrients on the pericarp’s coloring and the physiological causes. The treatments included spraying the concentrations0.5%of KCl (K),0.3%of CaCl2(Ca) and1.5%of MgCl2(Mg) solutions and their mixtures, and the check (CK) was sprayed the clean water.The test results are as follows:1. With the growth and development of fruits of different treatments and CK, the values of a and the contents of the anthocyanin in pericarp increased generally, the values of h, the contents of the chlorophyll in pericarp decreased generally. So, the pericarp’s reddening of different treatments and CK are associated with the increasing of the conmtent of anthocyanin in pericarp and the decreasing of the content of chlorophyll in pericarp, and almost has nothing to do with the content of carotenoids in pericarp.2. The content of the total acid in flesh of the different treatments and CK extremely significantly decrease during the period of fruit growth and development. The content of the total soluble sugar in flesh of all the treatments and CK significantly increase before May19th. From May19th to May22nd, the treatments K+Ca+Mg and Ca+Mg have no significant change, and the other treatments and CK significantly decrease. The ratio of sugar/acid in flesh of the different treatments and CK extremely significantly increase during the period of fruit growth and development. During the fruit mature period, the value of h in pericarp of the treatment Mg dropped to the bottom and was significantly lower than those of CK and the other treatments on May19th, and the content of the soluble sugar in flesh of the treatment Ca+Mg maintained the highest content and was significantly higher than that of CK on May22th, while h value of the treatment Ca+Mg made no significant difference from that of CK and was significantly lower than those of the other treatments. So the synchronization of the values of h in pericarp and the contents of the soluble sugar in flesh of the treatments Mg and Ca+Mg achieved the best on May19th and22th respectively. The treatment Mg successfully solved the problem that the peel kept green when the content of the soluble sugar in flesh rising to the top, and the treatment Ca+Mg successfully solved the problem that the content of the soluble sugar in flesh dropped when the pericarp coloring full.3. On May19th and22th,the content of anthocyanin in pericarp of Mg treatment was significantly higher than that of CK, and the content of chlorophyll and CK had no significant difference, indicating that the Mg treatment overcome pericarp "stay green" phenomenon due to the higher content of anthocyanin.4. The content of the total K in pericarp of the different treatments and CK are similar before May19th, all are the first decline after rising, and the content of anthocyanin in pericarp of the different treatments and CK increase. In addition to Ca+Mg and K+Ca+Mg treatments, the dynamic change curve of the other treatments and CK all with an "M" type, the2peak appeare in May12th and19th. The content of the water-soluble K and the water-soluble Ca decrease in general before May19th, and all significantly increase after May19th. The content of the water-soluble Mg decrease in general. The different foliar nutrients treatments could all improve the contents of the corresponding elements in pericarp during the same period, especially fruit mature period.5. The partial correlation coefficients of the different treatments and CK between the contents of the water-soluble Ca and the water-soluble K, the total Ca and the water-soluble K, the total Mg and the total Ca were significant and indicated the positive relationship.6. To both CK and all the treatments, the univariate exponential correlation indexes of the contents of the anthocyanin to those of the water-soluble Mg, the total Mg and the total Ca in pericarp were significant and positive respectively, meanwhile, the univariate exponential correlation indexes of the contents of the chlorophyll to those of the water-soluble Mg and the total Ca in pericarp were both significant and negative respectively. In sumary, the co-operation of Ca and Mg in pericarp improved the pericarp’s coloring, and the treatment Mg improved the pericarp’s coloring by increasing the accumulations of Ca and Mg in pericarp.7. To both CK and the Mg treatment, the trend of the content of IAA,ABA,GA and Eth and the enzymatic activity of PaO,Chlase and UFGT are all showed a similar increasing trend, and the content of iPAs are showed a similar decline after a up trend.8. With the growth and development of fruits, there was no significant effect on the contents of IAA and Eth and the enzymatic activity of Chlase and PaO of Mg treatment in pericarp, and the content of iPAs of Mg treatment was significantly higher than that CK in May22nd only. From May15th to May22nd, Mg treatment significantly improved the ratio of the content of ABA and GA and the activity of UFGT. Thus, in fruit mature period, Mg treatment may be through the promotion of the ratio of the content of ABA and GA, and thus stimulate UFGT activity increased, ultimately promote the pericarp anthocyanin synthesis and improve the pericarp’s reddening, and then it could explain why Mg treatment solved the problem that the peel kept green when the content of the soluble sugar in flesh rising to the top.In a word, the effects of K and Ca and Mg applied in foliar nutrients can improve the pericarp’s coloring. Among them, the treatment Mg successfully solved the problem that the peel kept green when the content of the soluble sugar in flesh rising to the top. On the one hand, the treatment Mg improved the pericarp’s coloring by increasing the accumulations of Ca and Mg in pericarp. On the other hand, in fruit mature period, Mg treatment may be through the promotion of the ratio of the content of ABA and GA, and thus stimulate UFGT activity increased, ultimately promote the pericarp anthocyanin synthesis and improve the pericarp’s reddening, so the coloring of the Mg treatment ultimately better than that of CK.