钙镁叶面肥混合喷施减轻‘妃子笑’荔枝果实退糖现象原因分析

“妃子笑”荔枝在成熟期存在果肉的“退糖”现象,前期研究表明叶面喷施钙镁混合营养可以有效减缓果肉“退糖”问题,抑制果肉呼吸作用是原因之一,本文拟探讨叶面喷施钙镁肥对荔枝果肉磷酸戊糖途径（PPP）呼吸速率的影响。分别以树冠喷布0.3％氯化钙（Ca）、0.3％氯化镁（Mg）水溶液和0.3％氯化钙、0.3％氯化镁（Ca+Mg）混合水溶液为不同处理,以树冠喷布清水为对照（CK）,测定和比较不同发育期果肉主要可溶性糖含量、钙镁含量、PPP途径呼吸速率及其关键酶活性等的动态变化。结果表明,除Ca+Mg处理的果肉克服“退糖”现象外,其余处理和CK均出现“退糖”现象。不同处理通过提高果肉镁含量,而镁通过抑制PPP途径关键酶活进而抑制了PPP途径呼吸速率,从而抑制总呼吸速率,减少果肉糖份呼吸损耗。

Analysis on the causes of reducing the sugar-dropping phenomenon of' Feizixiao' litchi fruit by mixed spraying of calcium foliar fertilizer

"Feizixiao" litchi has "sugar-dropping" phenomenon in its flesh at the mature stage. Previous studies have shown that foliar spraying of calcium and magnesium mixed nutrition can effectively slow down the "sugar-dropping" problem of the flesh, and inhibiting the respiration of the flesh is one of the reasons. This paper intends to discuss the effect of foliar spraying of calcium and magnesium fertilizer on the respiration rate of pentose phosphate pathway (PPP) of litchi flesh. The dynamic changes of main soluble sugar content, calcium and magnesium content, respiration rate of PPP pathway and key enzyme activities of pulp at different development stages were measured and compared by spraying 0.3% calcium chloride (Ca), 0.3% magnesium chloride (Mg) aqueous solution and 0.3% calcium chloride (Ca+Mg) mixed aqueous solution to the crown as different treatments, and spraying clear water to the crown as control (CK). The results showed that except Ca+Mg treatment, the pulp of other treatments and CK all showed the phenomenon of "retrogression". Different treatments increased the content of magnesium in pulp, while magnesium inhibited the respiration rate of PPP pathway by inhibiting the key enzyme activities of PPP pathway, thus inhibiting the total respiration rate and reducing the respiration loss of sugar in pulp.