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Bulletin of Botanical Research ›› 2019, Vol. 39 ›› Issue (2): 181-191.doi: 10.7525/j.issn.1673-5102.2019.02.003

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Effects of Exogenous Hydrogen Peroxide on Growth and Resistance Physiology of Naked Oat Seedlings under Saline-alkali Mixed Stress

LIU Jian-Xin1,2, OU Xiao-Bin1,2, WANG Jin-Cheng1,2   

  1. 1. University Provincial Key Laboratory for Protection and Utilization of Longdong Bio-resources in Gansu Province, Qingyang 745000;
    2. College of Life Sciences and Technology, Longdong University, Qingyang 745000
  • Received:2018-11-05 Online:2019-03-05 Published:2019-03-20
  • Supported by:
    The National Natural Science Foundation of China(31560125);The Science and Technology Plan Project of Qingyang City in Gansu Province(KZ2014-19)

Abstract: The experiment was conducted to study whether exogenous hydrogen peroxide(H2O2) could improve the saline-alkali tolerance of naked oat(Avena nuda) seedlings and its physiological mechanism. Seedlings of naked oat(‘Dingyou No.6’) at three-leaf period cultured with perlite in a solar greenhouse were irrigated with the Hoagland nutrient solution containing 75 mmol·L-1 saline-alkali mixed solution(NaCl∶Na2SO4∶NaHCO3∶Na2CO3=12∶8∶9∶1) combination with dimethylthiourea(DMTU, a quencher of H2O2), and the leaves were sprayed with 0.01 mmol·L-1 H2O2. Seedlings were irrigated with Hoagland nutrient solution, and the leaves were sprayed with water served as the control. Seedlings growth, photosynthetic pigment content, active oxygen metabolism, and osmotic regulatory substance accumulation in leaves were measured. The results showed that exogenous H2O2 could alleviate the inhibition effects of saline-alkali mixed stress on seedlings growth of naked oat. Spraying H2O2 significantly increased root length, plant height, dry weight, the leaf chlorophyll a, chlorophyll b, total chlorophyll and carotenoid contents, and the superoxide dismutase, peroxidase, catalase, ascorbate peroxidase activities of naked oat seedlings under saline-alkali mixed stress, but decreased the contents of superoxide anion, H2O2, malondialdehyde, ascorbic acid, glutathione, and free amino acids. Treatments with spraying H2O2 also increased the contents of antioxidants(such as flavonoids, total phenols, procyanidins) and osmotic regulatory substance(such as soluble protein, soluble sugars, and proline) in leaves. The above effects of exogenous H2O2 were partially or completely reversed by DMTU. A comprehensive evaluation based on subordinate function analyses revealed that foliar spraying with H2O2 could improve the saline-alkali resistance of naked oat seedlings, and the promoting effect of H2O2 could be completely reversed by DMTU. Therefore, the exogenous H2O2 supply can increase saline-alkali adaptability in naked oat seedlings by regulating active oxygen metabolism and osmotic regulatory substance accumulation in leaves of naked oat plants under saline-alkali mixed stress.

Key words: H2O2, naked oat, saline-alkali mixed stress, active oxygen metabolism, osmotic regulatory substance

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