Research Institute for Biochemical Regulation, School of Agricultural Sciences, Nagoya University, 464, Chikusa, Nagoya, Japan.
Planta. 1992 Nov;188(4):611-8. doi: 10.1007/BF00197056.
The capabilities of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) seeds (caryopses) to degrade starchy reserves present in the endosperm tissue were compared under anaerobic conditions. The results showed that rice, a species highly tolerant to anoxia, can readily break down starch under anaerobiosis concomitant with germination, while wheat does not germinate and fails to degrade starch present in the endosperm. This clearly distinct behavior is likely the consequence of the successful inducible formation of α-amylase (EC 3.2.1.1.) in rice under anoxia, whereas the enzyme is not produced in wheat seeds. We found that rice seeds possess a set of enzymes allowing starch and its degradative products to be utilized under anoxic conditions. Wheat seeds were shown to germinate even under anoxia if fed glucose or sucrose exogenously. The overall results indicate that induction of α-amylase appears to be one of the factors permiting rice seeds to germinate in totally anaerobic environments.
比较了在厌氧条件下，水稻（Oryza sativa L.）和小麦（Triticum aestivum L.）种子（颖果）降解胚乳组织中淀粉储备的能力。结果表明，水稻是一种对缺氧高度耐受的物种，在萌发的同时很容易在厌氧条件下分解淀粉，而小麦则不萌发，也不能降解胚乳中的淀粉。这种明显不同的行为可能是由于在缺氧条件下，水稻中诱导形成了α-淀粉酶（EC 3.2.1.1.），而小麦种子中则不产生这种酶的结果。我们发现，水稻种子具有一套酶系统，允许在缺氧条件下利用淀粉及其降解产物。如果向小麦种子外源性添加葡萄糖或蔗糖，即使在缺氧条件下，种子也能萌发。总的结果表明，诱导α-淀粉酶的产生似乎是允许水稻种子在完全厌氧环境中萌发的因素之一。
