MECHANISMS OF STARVATION TOLERANCE IN PEARL-MILLET
MECHANISMS OF STARVATION TOLERANCE IN PEARL-MILLET
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DOI：
10.1104/pp.88.4.1381
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发表时间：
1988-12-01
期刊：
影响因子：
7.4
通讯作者：
VANDERWOUDE, WJ
中科院分区：
文献类型：
--
作者：
BAYSDORFER, C;WARMBRODT, RD;VANDERWOUDE, WJ
珍珠粟（Pennisetum glaucum [L.]）从生化和超微结构水平研究了幼苗对长期饥饿的反应。黑暗2天后，幼苗碳水化合物储备的大部分耗尽。在黑暗中8天后，呼吸速率下降到低于其初始值的50%，并且植物损失了其总蛋白质含量的一半。与碳水化合物消耗的情况不同，蛋白质损失仅限于特定器官。次生叶和茎（包括顶端分生组织）在此期间表现出很少或没有蛋白质损失。在初生叶、种子和根中，蛋白质损失很大。尽管在初级叶和根的蛋白质降解率高，这些器官没有表现出超微结构的变化，暗示组织，细胞，或亚细胞降解。此外，核酮糖二磷酸羧化酶在饥饿过程中没有优先降解，只有一个小的叶绿素含量下降后，在黑暗中8天。在第8 ~ 14天，初生叶顶端开始出现细胞死亡，并逐渐向下蔓延。芽和根的分生组织仍然活着长达14天。因此，植物的最终死亡是由于碳水化合物生产区域的丧失，而不是分生组织的丧失。我们认为，这些结果提供了一个解释珍珠粟表现出高度的饥饿耐受性。
The response of pearl millet (Pennisetum glaucum [L.]) seedlings to prolonged starvation was investigation at the biochemical and ultrastructural level. After 2 days of darkness the bulk of the seedling carbohydrate reserves were depleted. After 8 days in the dark the respiratory rate had declined to less than 50% of its initial value and the plants had lost half of their total protein content. Unlike the situation with carbohydrate depletion, protein loss was restricted to specific organs. The secondary leaf and stem (including the apical meristem) showed little or no protein loss during this period. In the primary leaf, seed, and roots, protein loss was substantial. In spite of the high rate of protein degradation in the primary leaf and roots, these organs showed no ultrastructural changes suggestive of tissue, cellular, or subcellular degradation. In addition, ribulose bisphosphate carboxylase was not preferentially degraded during starvation and only a small decline in chlorophyll content was observed after 8 days in the dark. During the period from 8 to 14 days, cell death started at the tip of the primary leaf and gradually spread downward. Both shoot and root meristems remained alive up to 14 days. Consequently, the eventual death of the plant was due to the loss of the carbohydrate-producing regions rather than the meristems. We suggest that these results provide an explanation for the high degree of starvation tolerance exhibited by pearl millet.