钙镁叶面肥对‘妃子笑’荔枝果肉柠檬酸积累的影响

Effects of Foliar Calcium and Magnesium Fertilizer on Citric Acid Accumulation of‘Feizixiao’Litchi Fruit

为探讨叶面喷施钙镁肥对‘妃子笑’荔枝果肉柠檬酸积累的影响,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),测定不同发育期果肉水溶性钙、水溶性镁、柠檬酸等含量变化及柠檬酸代谢相关酶活性的动态变化,并作多元线性相关分析。结果表明,柠檬酸含量呈“M”型动态变化趋势,Ca和Ca+Mg处理呈促进柠檬酸积累的趋势,而Mg处理呈先促进、后抑制的趋势;CK的ICL和Ca+Mg处理的CS酶活性分别与柠檬酸含量呈正相关;Ca+Mg处理的IDH活性与柠檬酸含量则呈负相关。果肉水溶性钙含量总体呈上升趋势,水溶性镁含量呈“上升、下降、上升、下降”的动态变化趋势;水溶性钙会抑制PEPC、ACO、CS这些酶的活性,仅CK的水溶性钙能提高PEPC的酶活性;水溶性镁能提高ICL和PEPC活性,对ACO、CS、IDH活性呈抑制作用。综上所述,喷施钙、镁叶面肥会影响果肉水溶性钙、镁含量,改变水溶性钙、镁等含量与柠檬酸相关酶活性之间的线性相关性,不同处理通过影响果肉柠檬酸积累而引起果肉总酸含量变化;Ca和Ca+Mg处理可能通过积累更多的柠檬酸而抑制果肉呼吸作用,进而使果肉减少糖分损失。

The effects of spraying foliar nutrition of calcium and magnesium on the citric acid accumulation of‘Feizixiao’litchi fruit was explored in this paper.During the period of fruit development,the fruits which were sprayed 0.3%magnesium chloride(Mg),0.3%calcium chloride(Ca)and the mixture(Ca+Mg),and water(CK)as the experimental materials to measure the contents of water-soluble calcium,water-soluble magnesium and citric acid,enzymes activities of related citric acid in fruit flesh,and made the multivariate linear correlation analysis.The content of citric acid showed an M-shaped trend.Ca and Ca+Mg treatments promoted the accumulation of citric acid,while Mg treatment promoted and then inhibited the accumulation of citric acid.The activities of ICL in CK and CS in Ca+Mg treatment were positively correlated with the content of citric acid,,respectively,however,the activity of IDH in Ca+Mg treatment was negatively correlated with it.The content of water-soluble calcium in the flesh showed an increased trend,and the content of water-soluble magnesium showed the trend of“increased,decreased,increased,decreased”.The water-soluble calcium could inhibit the activities of PEPC,ACO and CS,and the water-soluble calcium in CK could improve the activities of PEPC enzymes.The water-soluble magnesium could increase the activities of ICL and PEPC,and could inhibit the activities of ACO,CS,IDH.In conclusion,spraying the foliar nutrition of calcium and magnesium could affect the contents of water soluble calcium and magnesium,and could change the linear correlation between the contents of water soluble calcium,magnesium and the activities of related enzymes of citric acid.Different treatments affected the accumulation of citric acid in pulp and caused the change the total acid content in pulp.Ca and Ca+Mg treatment may inhibit pulp respiration through the accumulation of more citric acid to reduce the loss of sugar in pulp.