A Study of the relationship between anthocyanin biosynthesis and related enzymes activity in pyrus pyrifolia ＇Mantianhong＇ and its bud sports＇Aoguan＇

chinois. 【目的】研究红色砂梨花青苷合成与苯丙氨酸解氨酶（PAL）和查尔酮异构酶（CHI）活性的关系。【方法】以红色砂梨‘奥冠’及其亲本‘满天红’为试材，研究果实着色过程中果皮中花青苷含量和PAL、CHI酶活性的变化，以及套袋对花青苷合成和相关酶活性的影响。【结果】在果实着色过程中，‘奥冠’花青苷含量高于‘满天红’，两个品种花青苷变化趋势基本一致，呈现先升高后下降的趋势；两品种PAL活性总体变化趋势基本一致，都呈下降趋势，且‘奥冠’PAL酶活性总体低于‘满天红’；并且，两品种CHI酶活性呈现相似的变化趋势，总体呈上升趋势；同时，‘奥冠’CHI酶活性高于‘满天红’；套袋抑制了‘奥冠’CHI酶的活性，也抑制了花青苷的合成，但对PAL酶活性的影响不明显；解袋后CHI酶活性和花青苷含量迅速上升，均超过了对照。但解袋对‘奥冠’果实PAL酶活性的影响不明显；并且，套袋‘奥冠’花青苷含量在果实成熟时下降。【结论】红色砂梨花青苷含量在果实着色早期上升，接近果实商品成熟期下降。PAL不是红色砂梨花青苷合成的关键酶，CHI与着色期砂梨花青苷含量关系密切。解袋后，‘奥冠’通过提高CHI酶的活性促进花青苷的合成。套袋试验表明：砂梨花青苷果实成熟时的降解不单是由光诱发的。光是花青苷合成的必需因素，同时又促进花青苷的降解。

anglais. [Objective] Study the relationship between anthocyanin biosynthesis and activities of PAL, CHI enzymes in Pyrus pyrifolia. [Method] Changes in the level of anthocyanin and the activities of enzymes of anthocyanin biosynthesis including plenylalanine ammonialyase （PAL）, chalcone ismoerase （CHI） were studied in the pericarp of Pyrus pyrifolia ＇Mantianhong＇ and ＇Aoguan＇ during the pigment formation period. Bagging treatment was also conducted to manipulate anthocyanin synthesis and the activities of related enzymes during the pigment formation period. [Result] The results demonstrated that the content of anthocyanin of ＇Aoguan＇ was higher than that of ＇Mantianhong＇. However, has the similarly changing trend of the content of anthocyanins was found both in ＇Aoguan＇ and ＇Mantianhong＇, highest amount of anthocyanin of two varieties was found in immature fruit, lowest amount in mature fruit. Meanwhile, similar changing trends of activities of PAL and CHI were also observed in both varieties. The activity of PAL was decreased during the pigment formation period. The activity of PAL of ＇Aoguan＇ was lower than that of ＇Mantianhong＇. Whereas the activity of CHI was increased as fruit ripened. The activity of CHI of ＇Aoguan＇ was higher than that of ＇Mantianhong＇. Bagging treatment inhibited the activity of CHI anthocyanin synthesis, whereas debagging enhanced both the activity of CHI and anthocyanin synthesis as well. However, it did not influence the activity of PAL. The activity of CHI and the amount of anthocyanin in ＇Aoguan＇ pericarp after removal of bags was higher than that of control. However, debagging had no apparent influence on the activity of PAL. Anthocyanin of ＇Aoguan＇ with bagging was decreased towards harvest. [ Conclusion ] The content of anthocyanin of Pyrus pyrifolia was increased at the beginning of fruit coloration period, decreased towards fruit harvest. The activity of PAL was not a key enzyme for colouration, while CHI activity was closely related to the synthesis of anthocyanin. Debagging enhanced the activity of CHI and anthocyanin synthesis. Bagging treatment also showed that anthocyanin degradation was not induced only by light. Light appeared to be necessary for anthocyanin synthesis in pears, and also a factor inducing the decrease of colour through degradation of anthocyanin.