H2O2浸种对低温胁迫下花生种子萌发的调控作用

Effects of seed soaking with H2O2 on seed germination of peanut under low temperature conditions

为了研究H2O2浸种对低温胁迫下花生种子萌发的调控作用,本研究以白沙1016和花育9122两个花生品种为材料,通过种子萌发试验,设置(22±1)℃常温对照和(12±1)℃低温处理,首先采用不同浓度的H2O2进行浸种预处理,分析了H2O2浸种对花生种子低温萌发相关指标的影响,筛选最适H2O2浸种浓度,然后采用最适H2O2浸种处理后,测定其对发芽花生种子胚中氧化损伤和活性氧含量、脯氨酸代谢相关指标的影响。结果表明,低温显著降低两个品种花生的相对发芽率、芽长/种长比、发芽指数及种子的活力指数,延长了平均露白时间,H2O2浸种预处理可显著缓解低温对花生种子萌发的抑制,以1%H2O2浸种效果最好。同时,H2O2浸种预处理还显著降低了H2O2的积累以及膜脂过氧化程度,促进了脯氨酸的积累,提高了脯氨酸合成酶鸟氨酸转移酶(OAT)和△1-吡咯琳-5-羧酸合成酶(P5CS)活性,抑制了脯氨酸降解限速酶脯氨酸脱氢酶(ProDH)活性。表明H2O2浸种预处理可通过调控脯氨酸代谢途径,促进低温条件下萌发花生种子内脯氨酸的积累,缓解氧化损伤,从而增强花生种子的低温萌发能力。

In order to investigate the regulative role of seed soaking with H2O2 on seed germination in peanut under low temperature(LT)conditions,two different peanut cultivars‘Baisha 1016’and‘Huayu 9122’were used to analyze the effects of seed soaking with different concentrations of H2O2 on seed germination,oxidative damage and reactive oxygen accumulation,and proline metabolism in peanut during germination stage.The results showed that LT treatment significantly postponed the time of radicals breaking through testa,reduced the relative germination rate,ratio of the length of hypocotyls to seeds,germination index,and seed vigor of both peanut cultivars.Low temperature treatment also resulted in the accumulation of malondialdehyde(MDA)and H2O2.Seed soaking with H2O2 could significantly alleviate the inhibitory effects of LT on seed germination of two peanuts,with 1%H2O2 shown the best mitigative effects.Meanwhile,seed soaking with 1%H2O2 markedly reduced H2O2 accumulation and lipid oxidation,increased proline content and activities of proline synthase(Ornithine aminotransferase and△1-pyrroline-5-carboxylate synthetase),while inhibited the activity of proline dehydrogenase in germinating peanut under LT conditions.Altogether,these results indicated that seed soaking with H2O2 could increase the germination ability of peanut seeds under LT through modulating proline metabolism,increase proline accumulation,and reduce LT-induced oxidative damage.