硅对过量锰胁迫下水稻根系抗氧化系统和膜脂质过氧化作用的调控机理

揭示Mn胁迫下Si对水稻根系抗氧化系统的影响机制，可为减轻水稻Mn毒害提供重要的理论依据和技术支持.因此，本研究通过水培试验，采用两个对Mn耐性不同的水稻品种，研究Si(1.5 mmol·L-1)对Mn(2 mmol·L-1)胁迫下水稻根系抗氧化系统的影响.结果表明，在Mn胁迫下，敏感品种新香优640(XXY)根系的超...

Silicon-mediated antioxidant reactions and membrane lipid peroxidation in roots of rice (Oryza sativa L.) exposed to excess manganese

The aim of the present work was to study the mechanism of the silicon-mediated antioxidant system in roots of rice grown under excess manganese (Mn) stress and Mn tolerance regulated by silicon (Si). Two rice varieties that differ in Mn tolerance were cultured in nutrient solution to study the effects of Si (1.5 mmol · L^-1) on antioxidant systems of rice roots under excess Mn stress (2 mmol · L^-1). For the Mn-sensitive cultivar (XXY), excess Mn significantly increased the activities of superoxide dismutase (SOD), the concentrations of ascorbate (AsA) and non-protein thiols (NPT), while it significantly decreased the activities of catalase (CAT) and ascorbate peroxidase (APX) and the concentrations of glutathione (GSH), thus leading to accumulation of high levels of malondialdehyde (MDA) in root tissues and destruction of plasma membrane integrity. However, excess Mn significantly increased the concentrations of GSH and AsA, but significantly decreased the activities of CAT and the concentrations of NPT, thus leading to accumulation of high level of MDA in the Mn-tolerant cultivar (ZLY). The addition of Si significantly decreased the concentrations of MDA and H₂O₂ in Mn-stressed root tissues, thereby mitigating the damage. Under excess Mn stress, application of silicon enhances the antioxidant activities of rice roots, and reduces lipid peroxidation and damage to the integrity of the apical membrane, thereby enhancing rice resistance to manganese toxicity. This alleviative effect is more pronounced in Mn-sensitive rice (XXY) than in Mn-tolerant rice (ZLY).