Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Ikenobe 2393, Miki, Kagawa 761-0795, Japan.
J Plant Physiol. 2010 Dec 15;167(18):1571-6. doi: 10.1016/j.jplph.2010.06.017. Epub 2010 Aug 19.
Physiological and metabolic responses to anoxia were compared for aerobically germinated seedlings of barley (Hordeum vulgare), oat (Avena sativa) and rice (Oryza sativa). Coleoptile growth of barley, oat and rice seedlings was suppressed by a 24 h-anoxic stress, but the growth of the rice coleoptiles was much greater than that of the barley and oat coleoptiles. ATP concentration in the anoxic rice coleoptiles was greater than that in the anoxic barley and oat coleoptiles. Concentrations of ethanol and activity of alcohol dehydrogenase (ADH) in the anoxic rice coleoptiles were also greater than those of the anoxic barley and oat coleoptiles, suggesting that ethanolic fermentation may be more active in the rice coleoptiles than in the barley and oat coleoptiles, where glycolysis and ethanolic fermentation are the main source of ATP production. Soluble sugar concentration in the anoxic rice coleoptiles was greater than that of the anoxic barley and oat coleoptiles. However, α-amylase, which catabolizes reserve starch to soluble sugars, was active in anoxic barley, oat and rice endosperms, and soluble sugar concentration in the anoxic barley, oat and rice endosperms was not significantly different. Therefore, anoxia stress may inhibit soluble sugar transport from the endosperms to the coleoptiles in barley and oat more than in rice. Since the availability of soluble sugar is essential for operation of glycolysis and fermentation in plant cells, ability for sugar transport from the endosperms to the coleoptiles may be one means to distinguish the coleoptile growth of these plant species in anoxia and anoxia tolerance of these plants.
对有氧萌发的大麦（Hordeum vulgare）、燕麦（Avena sativa）和水稻（Oryza sativa）幼苗的缺氧生理和代谢反应进行了比较。缺氧 24 小时会抑制大麦、燕麦和水稻幼苗的胚芽鞘生长，但水稻胚芽鞘的生长比大麦和燕麦胚芽鞘的生长大得多。缺氧水稻胚芽鞘中的 ATP 浓度大于缺氧大麦和燕麦胚芽鞘中的 ATP 浓度。缺氧水稻胚芽鞘中的乙醇浓度和酒精脱氢酶（ADH）活性也大于缺氧大麦和燕麦胚芽鞘中的乙醇浓度和 ADH 活性，表明乙醇发酵在水稻胚芽鞘中可能比在大麦和燕麦胚芽鞘中更为活跃，在大麦和燕麦胚芽鞘中，糖酵解和乙醇发酵是 ATP 产生的主要来源。缺氧水稻胚芽鞘中的可溶性糖浓度大于缺氧大麦和燕麦胚芽鞘中的可溶性糖浓度。然而，分解贮藏淀粉为可溶性糖的α-淀粉酶在缺氧的大麦、燕麦和水稻胚乳中都很活跃，而且缺氧的大麦、燕麦和水稻胚乳中的可溶性糖浓度没有显著差异。因此，缺氧胁迫可能比在水稻中更能抑制大麦和燕麦中从胚乳到胚芽鞘的可溶性糖运输。由于可溶性糖的可用性对于植物细胞中糖酵解和发酵的运转至关重要，因此从胚乳到胚芽鞘的糖运输能力可能是区分这些植物物种在缺氧条件下的胚芽鞘生长和这些植物的缺氧耐受性的一种手段。
