College of Agronomy, Guangxi University, Nanning 530004, PR China.
Plant Sci. 2012 Feb;183:123-30. doi: 10.1016/j.plantsci.2011.07.012. Epub 2011 Jul 28.
Nitric oxide (NO) has emerged as a key molecule involved in many physiological processes in plants. Whether NO reduces aluminum (Al) toxicity by regulating the levels of endogenous hormones in plants is still unknown. In this study, the effects of NO on Al tolerance and hormonal changes in the root apices of rye and wheat were investigated. Rye was more tolerant to Al stress than wheat according to the results of root elongation and Al content determined. Root inhibition exposed to Al was in relation to Al accumulation in the root apices. Al treatment decreased GA content and increased the values of IAA/GA and ABA/GA. Supplementation of NO donor sodium nitroprusside (SNP) reduced the inhibition of root elongation by increasing GA content and decreasing the values of IAA/GA and IAA/ZR under Al stress. NO scavenger 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylinidazoline-1-oxyl-3-oxide (cPTIO) can reversed SNP alleviating effect on Al toxicity. However, the regulating patterns of NO on the values of ABA/GA, GA/ZR and ABA/(IAA+GA+ZR) were different between rye and wheat. The values of ABA/GA and ABA/(IAA+GA+ZR) increased in rye, but decreased in wheat. The change of GA/ZR value was opposite. These results suggest that NO may reduce Al accumulation in the root apices by regulating hormonal equilibrium to enhance Al-tolerance in plants, which effect is more remarkable in Al-sensitive wheat.
一氧化氮 (NO) 已成为参与植物许多生理过程的关键分子。然而，NO 是否通过调节植物内源激素水平来减轻铝 (Al) 毒性仍不清楚。在这项研究中，研究了 NO 对黑麦和小麦根根尖 Al 耐性和激素变化的影响。根据根伸长和根根尖 Al 含量的测定结果，黑麦对 Al 胁迫的耐受性强于小麦。根抑制与 Al 在根根尖的积累有关。Al 处理降低了 GA 含量，增加了 IAA/GA 和 ABA/GA 的比值。NO 供体硝普钠 (SNP) 的补充通过增加 GA 含量和降低 Al 胁迫下的 IAA/GA 和 IAA/ZR 值，减少了根伸长的抑制。NO 清除剂 2-(4-羧基-2-苯基)-4,4,5,5-四甲基咪唑啉-1-氧-3-氧化物 (cPTIO) 可以逆转 SNP 对 Al 毒性的缓解作用。然而，NO 对 ABA/GA、GA/ZR 和 ABA/(IAA+GA+ZR) 值的调节模式在黑麦和小麦之间存在差异。ABA/GA 和 ABA/(IAA+GA+ZR) 值在黑麦中增加，而在小麦中降低。GA/ZR 值的变化相反。这些结果表明，NO 可能通过调节激素平衡来减少根根尖的 Al 积累，从而增强植物的 Al 耐性，在 Al 敏感的小麦中效果更为显著。
