Phosphorus deficiency enhances aluminum tolerance of rice (Oryza sativa) by changing the physicochemical characteristics of root plasma membranes and cell walls
Phosphorus deficiency enhances aluminum tolerance of rice (Oryza sativa) by changing the physicochemical characteristics of root plasma membranes and cell walls
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DOI：
10.1016/j.jplph.2013.09.012
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发表时间：
2014-01-15
影响因子：
4.3
通讯作者：
Wagatsuma, Tadao
中科院分区：
文献类型：
--
作者：
Maejima, Eriko;Watanabe, Toshihiro;Wagatsuma, Tadao
根表面的负电荷主要来自质膜磷脂的磷酸基和细胞壁果胶的羧基，它们通常被钙离子中和，有助于维持根的完整性。铝（Al）对植物的主要毒性作用是抑制根系伸长，这是由于铝与这些负位点紧密结合以换取钙。由于磷(P)限制条件下一些植物物种的根系磷脂和果胶浓度降低，我们假设在磷限制条件下生长的水稻（Oryza sativa L）幼苗由于其根系上的位点较少而表现出更强的铝耐受性。水稻幼苗先在有（+P）或没有（-P） P的培养液中生长，然后将幼苗转移到有或没有Al的培养液中，然后测定脂质、果胶、半纤维素、矿物质浓度以及Al耐受性。此外，研究了不同pH条件下磷处理幼苗的低钙耐受性。磷处理水稻根系中磷脂和果胶的含量低于磷处理水稻。正如预期的那样，磷处理的幼苗对铝的耐受性增强，同时根系和芽部的铝积累量减少。低磷诱导的铝耐受性增强不是由于根系抗氧化活性或有机酸分泌的增强，而是由于根系磷脂和果胶浓度的降低。此外，在低pH条件下，磷处理提高了根系对低钙的耐受能力。低磷诱导的低钙耐受性增强可能与磷脂和果胶较少的水稻根系维持PM和细胞壁结构所需的低钙有关。(C) 2013爱思唯尔有限公司版权所有。
The negative charge at the root surface is mainly derived from the phosphate group of phospholipids in plasma membranes (PMs) and the carboxyl group of pectins in cell walls, which are usually neutralized by calcium (Ca) ions contributing to maintain the root integrity. The major toxic effect of aluminum (Al) in plants is the inhibition of root elongation due to Al binding tightly to these negative sites in exchange for Ca. Because phospholipid and pectin concentrations decrease in roots of some plant species under phosphorus (P)-limiting conditions, we hypothesized that rice (Oryza sativa L) seedlings grown under P-limiting conditions would demonstrate enhanced Al tolerance because of their fewer sites on their roots. For pretreatment, rice seedlings were grown in a culture solution with (+P) or without (-P) P. Thereafter, the seedlings were transferred to a solution with or without Al, and the lipid, pectin, hemicellulose, and mineral concentrations as well as Al tolerance were then determined. Furthermore, the low-Ca tolerance of P-pretreated seedlings was investigated under different pH conditions. The concentrations of phospholipids and pectins in the roots of rice receiving -P pretreatment were lower than those receiving +P pretreatment. As expected, seedlings receiving the -P pretreatment showed enhanced Al tolerance, accompanied by the decrease in Al accumulation in their roots and shoots. This low P-induced enhanced Al tolerance was not explained by enhanced antioxidant activities or organic acid secretion from roots but by the decrease in phospholipid and pectin concentrations in the roots. In addition, low-Ca tolerance of the roots was enhanced by the -P pretreatment under low pH conditions. This low P-induced enhancement of low-Ca tolerance may be related to the lower Ca requirement to maintain PM and cell wall structures in roots of rice with fewer phospholipids and pectins. (C) 2013 Elsevier GmbH. All rights reserved.