Alternative Carbohydrate Reserves Used in the Daily Cycle of Crassulacean Acid Metabolism
Alternative Carbohydrate Reserves Used in the Daily Cycle of Crassulacean Acid Metabolism
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景天酸代谢日常循环中使用的替代碳水化合物储备
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
S. Sung
中科院分区：
文献类型：
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作者：
C. Black;J.;R. Doong;M. Angelov;S. Sung
每一天，在景天科酸代谢植物的绿色组织中都会发生一个巨大的连锁生物化学循环。这个互锁循环的功能，在其最简单的情况下，是为CAM植物光合作用提供大部分CO2。此外，该昼夜（24小时）循环通过两个辅助循环产生CAM组织的主要识别标记。一个周期涉及夜间酸化和第二天的损失，而第二个周期涉及夜间碳水化合物储备的消耗和第二天的补充。大约两个世纪前，本杰明·海恩（Benjamin Heyne，1815）正式写下了关于黎明时多汁绿色植物“酸如酸模”的味道和一天晚些时候酸度损失造成的“平淡味道”的文章。事实上，这些观察的确切起源在古代已经丢失，但肯定在罗马和圣经著作中有所提及。大约在世纪前，酸度的间接原因被认为是一种有机酸，后来的平淡味道与淀粉有关;但这些想法在理论上没有明确联系在一起，直到20世纪40年代末才进行定量研究。然后，随着中间代谢的主要部分的发现和额外的定量生物化学程序的出现，酸和淡味之间的日常相互关系的性质被定量地认识和测量。酸味主要由苹果酸引起，而淡味由脱酸加上淡味碳水化合物（例如多糖如淀粉）的相互合成引起。
Each day a massive interlocked biochemical cycle occurs in the green tissues of crassulacean acid metabolism plants. The function of this interlocked cycle, in its simplest context, is to furnish most of the CO2 for CAM plant photosynthesis. In addition, this diel (24 h) cycle produces the primary identifying marks of a CAM tissue through two ancillary cycles. One cycle involves a nocturnal acidification and its loss the next day, while the second concerns the depletion of a carbohydrate reserve at night and its replenishment the next day. Formally Benjamin Heyne (1815) is credited with writing, nearly two centuries ago, about the “acid as sorrel” taste of a succulent green plant at dawn and the “bland taste” caused by acidity loss later in the day. In fact, the exact origins of these observations are lost in antiquity, but certainly are referred to in Roman and Biblical writings. The circumstantial cause of the acidity was postulated to be an organic acid about a century ago and the bland taste later was associated with starch; but these ideas were not plainly coupled together in theory nor quantitatively studied until the late 1940s. Then, with the discovery of major portions of intermediary metabolism and the advent of additional quantitative biochemical procedures, the nature of the daily reciprocal relation between the acid and the bland taste was recognized and measured quantitatively. The acid taste is caused principally by malic acid, while the bland taste is caused by deacidification plus the reciprocal synthesis of a bland tasting carbohydrate, e.g. a polysaccharide such as starch.