‘妃子笑’荔枝果实着色不良原因的研究

A Study on the Causative Factors Retarding Pigmentation in the Fruit of `Feizixiao' Litchi

以着色不良的‘妃子笑’和着色良好的‘糯米糍’两个荔枝品种为试材 ,对比研究了果实成熟和着色的进程、果皮中色素组成、叶绿体的形态结构以及套袋处理对着色的效应。试验结果表明 ,妃子笑果实着色不良的主要原因为果皮中的高叶绿素含量。高叶绿素含量一方面加重了果面的底色 ,遮掩了花青苷色泽的显现 ;另一方面阻延了花青苷的合成 ,从而使着色落后于假种皮内的糖积累。当妃子笑假种皮中的含糖量达到最高时 ,果实着色面积尚不及 18%。若延迟采收 ,着色面积虽然能继续增加 ,但果肉含糖量减少 ,即所谓“退糖”现象。为了保证妃子笑的食用品质 ,生产上常不得不在着色尚差时采收 ,牺牲了商品的外观质量。用无纺布套袋能有效地降低叶绿素的含量 ,使果面的红色色泽更艳。

Two litchi cultivars, well-colored `Nuomici' and poor-colored `Feizixiao', were used to investigate peel pigments and chloroplast structure during fruit maturation and to examine the bagging effects. Coloration of `Feizixiao' seriously lagged behind sugar accumulation, the colored area was below 18% when sugar accumulation peaked. High chlorophyll concentration in the pericarp of `Feizixiao', which intensified the ground color, masked the display of anthocyanins as a surface color. In addition, high chlorophyll concentration interfered the synthesis of anthocyanins. These facts clearly indicated that high concentration and slow degradation of chlorophylls were the main causative factor impeding the surface color development in `Feizixiao'. Bagging fruit clusters with adhesive-bonded fabric effectively reduced the content of chlorophylls and hence improved the development and display of surface color.