氧化铈纳米颗粒种子引发对盐胁迫下辣椒种子萌发及幼苗生长的影响

Effects of cerium oxide nanoparticles seed priming on seed germination and seedling growth of pepper under salt stress

关键词:  纳米氧化铈, 辣椒, 种子引发, 盐胁迫, 幼苗生长

Key words:  cerium oxide nanoparticles(CeO₂NP_S), pepper, seed priming, salt stress, seedling growth

摘要:

氧化铈纳米颗粒(CeO₂NP_S),因具有较强的自由基清除能力和抗氧化酶特性,已被证明可提高植物的耐盐性,但其对辣椒种子引发作用和机制尚不明确。为揭示CeO₂NP_S种子引发处理辣椒对盐胁迫下的萌发及幼苗生长的影响,以辣椒品种(Capsicum annuum)茂蔬360为试验材料,设置了7个CeO₂NP_S浓度(0、0.05、0.1、0.2、0.3、0.4、0.5 mmol·L^-1),以未引发处理组为对照,研究不同浓度CeO₂NP_S种子引发处理后对盐胁迫下辣椒种子萌发、幼苗生物量和生理生化指标的影响。结果表明:(1)0.5 mmol·L^-1 CeO₂NP_S种子引发处理后的种子,其可溶性蛋白质、脯氨酸含量和过氧化氢酶(CAT)活性、抗坏血酸(AsA)含量和AsA/DHA比值显著提高,超氧阴离子(O₂^-)含量显著降低; 盐胁迫下,该处理种子的发芽率、发芽势、发芽指数、活力指数最大。(2)0.4 mmol·L^-1 CeO₂NP_S种子引发处理的幼苗在盐胁迫下的鲜重、干重和根长最大,幼苗的可溶性蛋白质、AsA含量和AsA/DHA比值均显著提高。综上认为,CeO₂NP_S引发处理不仅可通过降低种子水势、促进贮藏物质代谢和提高抗氧化能力提高种子在盐胁迫下的发芽率,还可在苗期通过增强蛋白合成和抗坏血酸-谷胱甘肽循环(AsA-GSH)促进盐胁迫下幼苗的生长。

Abstract:

Cerium oxide nanoparticles(CeO₂NP_S)have been shown to improve the salt tolerance of plant due to the potential to eliminate free radicals and the antioxidation properties. However, the effects and mechanisms of seed priming with CeO₂NP_S on pepper plant are unclear. To reveal impacts of CeO₂NP_S seed priming on the germination and seedling growth of peeper plants under salt stress, using the Maoshu 360 variety of pepper(Capsicum annuum)as material, a total of seven concentrations of treatments(0, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5 mmol·L^-1)and a control of un-treatment were carried out to investigate effects of CeO₂NP_S seed priming on seed germination rate, seedling biomass, and physiological and biochemical indexes under salt stress. The results were as follows:(1)In the seed priming with 0.5 mmol·L^-1 CeO₂NP_S, soluble protein, content of proline, activity of catalase(CAT), content of ascorbic acid(AsA)and ratio of AsA/DHA significantly increased and levels of the superoxide anion(O₂^-)significantly decreased. There was no loss of viability for the seeds primed with cerium oxide nanoparticles. Indeed their germination rate and germination potential were enhanced under salt stress, and their germination index, and vigor index were improved under salt stress.(2)Under salt stress, seedlings from seeds primed with 0.4 mmol·L^-1 CeO₂NP_S showed the highest fresh weight, dry weight, and root length; additionally, soluble protein content, AsA content and AsA/DHA ratio were also improved. In conclusion, seed priming with CeO₂NP_S can not only enhance seed germination under salt stress by decreasing seed water potential, accelerating storage substances metabolism and improving antioxidant capacity but also promote seedling growth through boosting protein synthesis and ascorbic acid-glutathione cycle(AsA-GSH).