叶面喷施混合钙镁肥克服‘三月红’荔枝果皮“滞绿”现象的成因初探

为了探究叶面喷施混合钙镁肥克服‘三月红’荔枝果皮“滞绿”现象的生理生化机制,以‘三月红’荔枝的成年单株为试验材料,以叶面喷施混合钙镁肥为处理,以喷清水为对照（CK）,观测其果皮色素、内源激素含量以及相关酶的活性。结果表明,处理与CK的色调角（h值）、叶绿素和生长素（IAA）等含量总体呈下降趋势;糖酸比和花色素苷、乙烯（Eth）、脱落酸（ABA）、赤霉素（GA₃）等含量及类黄酮糖基转移酶（UFGT）、叶绿素单加氧酶（PaO）、叶绿素酶（Chlase）等活性总体呈上升趋势;处理果实的h值在3月29日、4月5日和4月12日显著低于CK;花色素苷含量在4月5日至4月12日之间则显著高于CK;处理的叶绿素含量在4月5日和4月12日显著低于CK;处理的糖酸比在4月5日后显著高于CK;处理的Eth含量在3月29日及4月8日、15日显著高于CK;处理的果皮ABA含量在4月5日后显著高于CK;处理的IAA含量在4月1日显著低于CK,4月12日显著高于CK;处理的UFGT活性在3月29日显著低于CK,4月8、12日显著高于CK;处理的PaO活性在4月1日、8日、12日显著高于CK;UFGT活性与ABA、Eth含量极显著正相关;PaO活性与Eth含量极显著正相关;花色素苷含量与ABA、Eth含量和UFGT活性极显著正相关;叶绿素含量与Eth含量和UFGT、PaO活性分别极显著负相关,与ABA显著负相关;处理与CK的GA₃含量、Chlase活性全程同期间均无显著差异。可见,喷施混合钙镁肥处理可促进着色而克服果皮“滞绿”现象,主要是通过提高Eth与ABA等含量、进而提高UFGT和PaO活性等促进花色素苷的合成和叶绿素降解,使得果皮在果肉糖酸比最高时提前着色,成功克服了果皮“滞绿”现象。

Causes of Overcoming the Phenomenon of ‘Sanyuehong’ Litchi Peel “Stagnation Green” by Applying Foliar Mixed Fertilizer of Calcium and Magnesium

In order to research the physiological and biochemical mechanism on overcoming the phenomenon of ‘Sanyuehong’ litchi “stagnation green” by applying foliar mixed fertilizer of calcium and magnesium, the adult fruit trees of ‘Sanyuehong’ litchi were used as the experimental materials, and the leaves were treated by spraying mixed fertilizer of calcium and magnesium, and the control (CK) was treated with clear water, then the contents of peel pigment, endogenous hormones and the activities of related enzymes were measured. The results showed that the h value, chlorophyll and IAA contents of treatment and CK were decreasing. The ratio of sugar/acid and the contents of anthocyanin, Eth, ABA, GA₃ and the activities of UFGT, PaO, Chlase in the treatment and CK showed an overall rising trend. The h value of treatment fruit was significantly lower than that of CK on March 29, April 5 and 12. The content of anthocyanin was significantly higher than that of CK during the period from 5 April to 12 April. The content of chlorophyll in the treatment was significantly lower than that of CK on April 5 and 12. The ratio of sugar/acid of the treatment was significantly higher than that of CK after April 5. The content of Eth of the treatment was significantly higher than that of CK on March 29, April 8 and 15. The content of ABA of the treatment was significantly higher than that of CK after April 5. The content of IAA of the treatment was significantly lower and higher than that of CK on April 1and 12 respectively. The activity of UFGT of the treatment was significantly lower than that of CK on March 29 and significantly higher than that of CK on April 8 and 12. The activity of PaO of the treatment was significantly higher than that of CK on April 1, 8 and 12. The activity of UFGT was extremely significantly positively correlated with the content of ABA and Eth. The activity of PaO was extremely significantly positively correlated with the content of Eth. The content of anthocyanin was extremely significantly positively correlated with ABA, Eth contents and UFGT activity. The content of chlorophyll was extremely significantly negatively correlated with Eth content, UFGT and PaO activity, and significantly negatively correlated with ABA content. There was no significant difference in GA₃ content and Chlase activity between the treatment and CK. It could be seen that spraying mixed fertilizer of calcium and magnesium could ppromote coloring and overcome the phenomenon of “stagnation green” in peel, it mainly increased the Eth and ABA content, and then improved the UFGT and PaO activity, and then promoted the synthesis of anthocyanin and the degradation of chlorophyll, which making the peel coloration in advance when the pulp glycolic acid ratio was at its highest, and successfully overcomed the phenomenon of “stagnation green”. It could be used as a cultivation technique to overcome the phenomenon of Sanyuehong litchi peel “stagnation green” that applying foliar mixed fertilizer of calcium and magnesium.