Biotechnology Bulletin ›› 2023, Vol. 39 ›› Issue (7): 160-172.doi: 10.13560/j.cnki.biotech.bull.1985.2022-1253

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Mechanism of Melatonin Seed Priming in Improving Salt Tolerance of Capsicum annuum

WEI Xi-ya(), QIN Zhong-wei, LIANG La-mei, LIN Xin-qi, LI Ying-zhi()   

  1. College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang 524088
  • Received:2022-10-11 Online:2023-07-26 Published:2023-08-17
  • Contact: LI Ying-zhi E-mail:1534536534@qq.com;liyz@gdou.edu.cn

Abstract:

Melatonin can enhance plant salt tolerance, but its effect and mechanism of improving plant salt tolerance through seed priming are rarely reported. In order to investigate the effects of melatonin(MT)seed priming on the growth and physiological characteristics of pepper seedlings under salt stress, its influences on the growth, photosynthetic characteristics, antioxidant metabolism and osmotic regulation of pepper seedlings under salt stress were studied using ‘Maoshu 360’ as material. The results showed that MT seed priming significantly alleviated the adverse effects of salt stress on the growth of pepper plants. Compared with seed without seed priming treatment, seed priming treatments with different concentrations of melatonin significantly improved the growth of pepper seedlings under salt stress, specifically, these indexes plant root length, above ground height, stem fresh weight, leaf fresh weight, root fresh weight, FV'/Fm', Qp, NPQ, Fo, FV/Fm and chlorophyll content increased. Physiological analysis showed that the contents of malondialdehyde, hydrogen peroxide and superoxide anion in the leaves of pepper under salt stress significantly reduced by seed priming with different concentrations of melatonin. The contents of soluble sugar, soluble protein, proline, AsA and DHA in the leaves significantly increased. The activities of POD, SOD, APX and GR significantly increased. In addition, melatonin seed priming treatment significantly increased the content of K+ in the leaves, stems and roots, and decreased the content of Na+ and Na+/ K+ in the leaves of seedlings under salt stress. The above results showed that 100 μmol/L melatonin seed priming treatment had the best effect, which significantly improved the tolerance to soil salt, reduced the absorption of Na+ by plants, and alleviated the damage of salt stress to plants.

Key words: salt stress, Capsicum annuum, melatonin, leaf blade, anti-oxidation, regulation of osmosis