摘要
【目的】研究二价金属离子和传统抑制剂对刺梨果实维生素C合成的调控作用。【方法】以‘贵农5号’刺梨为材料,采用离体喂饲和活体注射相结合的方法,研究Ca2+、Mg2+、Cu2+等二价金属离子及吖啶黄素、石蒜碱等有机抑制剂对刺梨果实半乳糖内酯脱氢酶(GalLDH)活性和维生素C(AsA)合成的影响。【结果】Ca2+、Mg2+两种离子对初纯化的GalLDH酶活性有一定的促进作用,Cu2+则显著抑制其活性;当用金属离子与AsA合成底物半乳糖内酯(GalL)共同喂饲果肉时,Ca2+、Mg2+两种离子未有效促进AsA合成,Cu2+处理下的刺梨果肉中AsA含量甚至显著降低;在刺梨果实发育过程中,注射Ca2+对活体果实AsA合成有明显促进作用,Mg2+的作用不明显,而Cu2+依然表现出对AsA合成的抑制作用。吖啶黄素能抑制初纯化GalLDH酶液约70%的活性,而石蒜碱的抑制作用较小(约30%),但两者在离体喂饲处理中对AsA合成表现出相似的抑制效果;活体注射处理时,吖啶黄素在处理后期对AsA合成表现出较明显的抑制作用,石蒜碱则无此效应。【结论】外源增Ca2+可促进刺梨果实AsA合成和积累,而Cu2+和吖啶黄素则有抑制作用。
【Objective】 The effects of divalent cations and organic inhibitors on GalLDH activity and AsA biosynthesis in Rosa roxburghii fruits were studied.【Method】Fruits of Rosa roxburghii Tratt cv.Guinong 5 was used to investigate the effects of divalent cations Ca2＋,Mg2＋,and Cu2＋ and organic inhibitors acriflavine and lycorine on GalLDH activity and AsA biosynthesis,by using the methods of incubation in vitro and injection in vivo.【Result】The results showed that the activity of purified GalLDH was promoted by Ca2＋ and Mg2＋,but extremely inhibited by Cu2＋.Even so,when flesh tissues of the fruit was incubated respectively in the mixed solution of the metal ions together with L-galactono-1,4-lactone（GalL）,an immediate substrate of AsA biosynthesis,both Ca2＋ and Mg2＋ could not effectively improve the AsA biosynthesis,while the AsA content in the flesh tissues pre-incubated in presence of Cu2＋ decreased markedly.AsA biosynthesis and accumulation in developing fruit was obviously promoted by injection of Ca2＋ solution and inhibited by that of Cu2＋,but not influenced by Mg2＋.Acriflavine,suggested an organic inhibitor of AsA biosynthesis,was able to inhibit the activity of Rosa roxburghii GalLDH about 70%,but lycorine,another specific inhibitor of AsA biosynthesis,had a very slight influence on it.The similar inhibitory effect was detected in incubating fresh fruit tissues in the presence of the two inhibitors together with GalL respectively,although injection of acriflavine presented a visible inhibiting effect on AsA accumulation in developing fruit,and lycorine had no influence.【Conclusion】Exogenous Ca2＋ could promote but Cu2＋ or acriflavine inhibit AsA biosynthesis in Rosa roxburghii fruits.
出处
《中国农业科学》
CAS
CSCD
北大核心
2012年第6期1144-1149,共6页
Scientia Agricultura Sinica
基金
贵州省优秀青年科技人才培养计划项目(黔科合人字200704)
国家自然科学基金项目(31060257)
贵州省优秀科技教育人才省长专项资金项目(黔省专合字201012)
