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Acta Prataculturae Sinica ›› 2024, Vol. 33 ›› Issue (8): 122-132.DOI: 10.11686/cyxb2023369

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Effects of different exogenous substances on the seed germination, seedling growth, and physiology of Melilotus suaveolens under salt, alkali, and drought stress

Ting-ting ZHANG1(), Yu-le LIU1, Hong CHEN1, Ling-xin XU1, Xiang-wei CHEN2, En-heng WANG2, Jun-xin YAN1()   

  1. 1.College of Landscape Architecture,Northeast Forestry University,Harbin 150000,China
    2.College of Forestry,Northeast Forestry University,Harbin 150000,China
  • Received:2023-10-09 Revised:2023-11-20 Online:2024-08-20 Published:2024-05-13
  • Contact: Jun-xin YAN

Abstract:

The aim of this study was to determine the best exogenous substance, and its optimal concentration, to promote the seed germination and seedling growth of Melilotus suaveolens under salt, alkali, and drought stress. Seeds of M. suaveolens were germinated in Petri dishes on filter paper with gibberellin (GA) and melatonin (MT) at various concentrations. The effects of these substances on the seed germination and seedling growth of M. suaveolens, as well its responses to 6-h salt, alkali, and drought stress treatments, were evaluated. The results showed that 200 mg·L-1 GA was the best treatment to promote seed germination, and 50 μmol·L-1 MT was the best treatment to improve the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in seedlings under salt stress. Under alkali stress, the maximum hypocotyl length of seedlings was in the 200 μmol·L-1 MT treatment. Under drought stress, the maximum germination rate and radicle length were in the 100 mg·L-1 GA treatment. According to a multivariate evaluation using a membership function method, the best exogenous substance for alleviating salt stress was GA, and the optimal concentration was 200 mg·L-1. The best exogenous substance for alleviating alkali stress and drought stress was MT, and the optimal concentration was 50 and 100 μmol·L-1, respectively. In conclusion, MT and GA can promote the seed germination and seedling growth of M. suaveolens under salt, alkali, and drought stress. These findings provide reference data for improving the tolerance of M. suaveolens to salt, alkali, and drought stress.

Key words: exogenous substances, salt, alkali and drought stress, Melilotus suaveolens, seed germination, seedling growth, antioxidant enzyme activity