信号分子H2O2调节抗氧化系统提高高羊茅耐热性研究

采用盆栽试验,利用10 mmol/L的H₂O₂对冷季型草坪草高羊茅进行叶面喷施处理,研究外源低浓度H₂O₂对高羊茅叶片中抗氧化系统的调控作用及其对高羊茅抗热性的影响。结果表明,H₂O₂可能作为信号分子预先增加抗氧化酶的活性,改变抗氧化剂的浓度,从而减轻随后发生的热胁迫对草坪草造成的氧化伤害;在胁迫过程中POD和CAT活性在H₂O₂预处理后增加不显著,热胁迫本身增加了POD的活性,但是降低了CAT活性,POD对于提高高羊茅的耐热性可能具有更重要的作用;外源H₂O₂显著影响了高羊茅叶片中的AsA-GSH循环,其中处理植株中的APX、GPX和GR的活性在热胁迫过程中增加20%～110%,GSH/GSSG下降了80%,与高羊茅抗热性的提高密切相关。可见信号分子H₂O₂可以通过调控高羊茅的抗氧化系统提高其抗热性。

The signaling molecule H2O2 improved the heat-tolerance system of Festuca arundinaceaby up-regulating antioxidative activity

Cool-season turfgrass Festuca arundinacea was pretreated with 10 mmol/L H₂O₂ in pot experiments, and the regulation of the antioxidative system by exogenous H₂O₂ and its effects on heat-tolerance were studied. Exogenous H₂O₂ may activate the defensive system in F. arundinacea ahead of heat stress, and alleviate oxidative damage resulting from subsequent heat stress. CAT and POD activities were not significantly increased by exogenous H₂O₂ treatment. Heat stress itself increased POD activity, and POD may play a more important role in improving heat resistance of the turfgrass. H₂O₂ significantly affected the AsA-GSH cycle in F. arundinacea. APX, GPX and GR activities increased 20%-110% and GSH/GSSG significantly decreased 80% in the cycle, and were closely associated with the acquirement of heat tolerance in F. arundinacea. The signaling molecule H₂O₂ can improve the heat-tolerance of F. arundinacea by regulating the antioxidative system.