外源NO对渗透胁迫下茶树种子萌发的影响

Effects of exogenous nitric oxide on seed germination of Camellia sinensis(L.) O.Kuntze under osmotic stress

为探讨NO对渗透胁迫下茶树(Camellia sinensis(L.)O.Kuntze)种子萌发的影响,用20%PEG6000模拟干旱处理,分别添加0、20、50、100、200和300μmol·L^(-1)硝普钠(SNP,NO外源供体)。结果表明,外源NO能显著促进渗透胁迫下茶树种子的萌发,且呈现一定的浓度效应,在NO供体SNP浓度为100μmol·L^(-1)时效果最佳。随着外源SNP浓度的增加,茶树种子的萌发及生长受到了抑制,种子的发芽率、发芽指数、根长和活力指数均呈降低的趋势。进一步研究表明100μmol·L^(-1)的SNP能促进SOD、POD、CAT、APX、GR和GPX等抗氧化酶活性的提高,降低MDA含量及相对电导率。推测添加外源NO后,抗氧化酶活性提高,降低了茶树种子的氧化损伤,从而缓解了渗透胁迫对茶树种子萌发的抑制作用。

In order to investigate the effects of exogenous nitric oxide （NO） on seed germination of （Camellia sinensis （L.） O.Kuntze） under osmotic stress, the seeds of tea plants were treated with 20% PEG6000 and SNP at 0, 20, 50,100, 200 and 300 μmol· L-1, separately. The results showed that exogenous nitric oxide could significantly promote the germination of tea seeds under osmotic stress, and the optimal concentration was 100 μmol· L-1. With increasing SNP concentration, the seed germination and seedling growth were suppressed; meanwhile, the seed germination rate, germination index, root length and vigor index were decreased. A further study suggested that 100 μmol· L-1 SNP could promote enzyme activities of SOD, POD, CAT, APX, GR and GPX, and it also reduced the MDA concentration and relative electrical conductivity under osmotic stress. The results suggested that NO could alleviate oxidative damages of tea seeds by increasing the activities of antioxidant enzymes; therefore, NO may play an important role in alleviation of osmotic stress in tea seeds.