Colmer T D, Cox M C H, Voesenek L A C J
School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, 35 Stirling Highway, Crawley 6009 WA, Australia.
New Phytol. 2006;170(4):767-77. doi: 10.1111/j.1469-8137.2006.01725.x.
Adventitious roots of rice (Oryza sativa) acclimatize to root-zone O(2) deficiency by increasing porosity, and induction of a barrier to radial O(2) loss (ROL) in basal zones, to enhance longitudinal O(2) diffusion towards the root tip. Changes in root-zone gas composition that might induce these acclimatizations, namely low O(2), elevated ethylene, ethylene-low O(2) interactions, and high CO(2), were evaluated in hydroponic experiments. Neither low O(2) (0 or 0.028 mol m(-3) O(2)), ethylene (0.2 or 2.0 microl l(-1)), or combinations of these treatments, induced the barrier to ROL. This lack of induction of the barrier to ROL was despite a positive response of aerenchyma formation to low O(2) and elevated ethylene. Carbon dioxide at 10 kPa had no effect on root porosity, the barrier to ROL, or on growth. Our findings that ethylene does not induce the barrier to ROL in roots of rice, even though it can enhance aerenchyma formation, shows that these two acclimatizations for improved root aeration are differentially regulated.
水稻（Oryza sativa）的不定根通过增加孔隙度以及在基部区域诱导形成径向氧气损失（ROL）屏障来适应根际氧气缺乏，以增强氧气向根尖的纵向扩散。在水培实验中评估了可能诱导这些适应性变化的根际气体成分变化，即低氧、乙烯升高、乙烯 - 低氧相互作用和高二氧化碳。低氧（0或0.028 mol m(-3) O(2)）、乙烯（0.2或2.0 μl l(-1)）或这些处理的组合均未诱导ROL屏障的形成。尽管通气组织形成对低氧和乙烯升高有积极反应，但仍未诱导出ROL屏障。10 kPa的二氧化碳对根孔隙度、ROL屏障或生长没有影响。我们的研究结果表明，乙烯不会诱导水稻根中的ROL屏障，尽管它可以增强通气组织的形成，这表明这两种改善根系通气的适应性变化受到不同的调节。
