早红考密斯及其芽变果实中花青素含量与相关酶活性变化的研究

以西洋梨早红考密斯及其绿色芽变果实为材料,研究了果实发育期间果皮色泽、花青苷含量及其相关酶活性变化.结果显示:(1)早红考密斯果皮色泽从成熟前的暗红色逐渐变为成熟时的浅红色,并在色泽分布不均匀的地方显出黄色底色,色泽指数(a*)值从花后45 d的16.4降低到成熟时的7.4,降低54.9%;花青苷含量从成熟前的258.4μg?g-1降到成熟时的118.3μg?g-1;早红考密斯果皮色泽和果皮花青苷含量具有密切的相关性.(2)早红考密斯的绿色芽变在果实发育的前期检测不到花青苷,发育后期果实向阳部出现浅红晕,但花青苷含量极低,与亲本差异极显著.(3)果实发育期间,两品种间苯丙氨酸解氨酶(PAL)变化趋势相似,总体呈下降趋势,且早红考密斯的活性总体低于其绿色芽变;两品种查耳酮异构酶(CHI)活性总体变化趋势基本一致,均呈现缓慢上升的趋势,在前期绿色芽变的CHI活性高于其亲本,后期低于亲本;类黄酮3-O-葡(萄)糖基转移酶(UFGT)活性在两品种间的差异较大,在整个果实发育期间早红考密斯的UFGT活性远高于其绿色芽变.研究表明,早红考密斯果皮色泽变化主要由花青苷的含量不同引起;PAL和CHI不是绿色芽变的直接原因;UFGT与花青苷合成密切相关,绿色芽变果皮中UFGT活性显著降低.

Relationship between Anthocyanin Biosynthesis and RelatedEnzyme Activities in Pyrus communis L.cv.'Early Red Comice' and Its Green Bud Mutant

Anthocyanin content and the activities of related enzymes of anthocyanin biosynthesis including phenylalanine ammonialyase(PAL),chalcone ismoerase(CHI) and flavonoid 3-O-glucosyltransferase(UFGT) were studied in the pericarp of Pyrus communis L.cv.‘Early Red Comice’ and its green bud mutant during the fruit development.The results showed,the ‘Early Red Comice’ entailed the attainment of the best red color and highest anthocyanin content a month or more before harvest and a tendency of color to fade toward harvest,the anthocyanin content was decreased from 258.4 μg·g-1 to 118.3 μg·g-1 in pericarp of harvest fruit;the activity of PAL revealed similar changing trends in both varieties and decreased during the fruit development.Whereas the activity of CHI was increased slowly as fruit ripened.The activity of UFGT demonstrated significantly difference in both varieties in the experiment.The activity of UFGT was higher significantly than that in green bud mutant.The activity of UFGT was closely related to the synthesis of anthocyanin.In summary,the index of color of ’Early Red Comice’and its bud green mutant is anthocyanin content and UFGT activity.