蔗糖对胡萝卜组织培养中叶绿素合成的抑制作用：转化酶的作用。

Sucrose suppression of chlorophyll synthesis in carrot tissue cultures: The role of invertase.

机构信息

Biology Department, Queen Elizabeth College, London.

出版信息

Planta. 1971 Jun;101(2):122-32. doi: 10.1007/BF00387623.

Abstract

Free space invertase activities were determined in carrot callus strains CRT1 and CRT2 grown under conditions in which sucrose suppression of chlorophyll synthesis occurred in CRT1 but not CRT2. CRT2 possessed a high free space acid invertase activity (pH optimum 5.0 Km for sucrose 3.1×10(-3)M) while CRT1 lacked this enzyme. [U-(14)C] sucrose introduced into the free space of calluses was rapidly inverted by CRT2, but not by CRT1.Despite their different invertase levels, CRT1 and CRT2 showed similar sucrose uptake rates and took up [U-(14)C-glucosyl] sucrose and [5-T-glucosyl] sucrose from external bathing media essentially without prior inversion.It is concluded that acid invertase in callus tissue relieves the suppression of chlorophyll synthesis caused by sucrose in the free space. The invertase may in some circumstances hydrolyse sucrose before uptake, but is not an essential part of the sucrose uptake mechanism in carrot tissue cultures.

摘要

游离空间蔗糖酶活性在 CRT1 和 CRT2 胡萝卜愈伤组织培养中被测定，在 CRT1 中，蔗糖抑制叶绿素合成的条件下，而 CRT2 中则没有出现这种情况。CRT2 具有较高的游离空间酸性蔗糖酶活性（pH 最适值 5.0，Km 为蔗糖 3.1×10（-3）M），而 CRT1 则缺乏这种酶。[U-（14）C]蔗糖迅速被 CRT2 反转，但 CRT1 则不行。尽管它们的蔗糖酶水平不同，但 CRT1 和 CRT2 表现出相似的蔗糖摄取率，并从外部浸浴介质中摄取[U-（14）C-葡萄糖基]蔗糖和[5-T-葡萄糖基]蔗糖，基本上没有先反转。结论是，愈伤组织中的酸性蔗糖酶缓解了游离空间中蔗糖对叶绿素合成的抑制。在某些情况下，蔗糖酶可能在摄取前水解蔗糖，但不是胡萝卜组织培养中蔗糖摄取机制的必要组成部分。