Effect of Glycine Betaine on Seed Germination and Antioxidant Enzymes in Seedlings of Astragalus membranaceus under Salt Stress

  Objective   Effects of exogenous treatment of glycine betaine (GB) on seeds and seedlings of Astragalus membranaceus under salt stress was studied to decipher the stress alleviation.

  Method   The seeds and seedlings of A. membranaceus (Fisch.) Bge.var.mongholicus (Bge.) Hsiao (Am H) and A. membranaceus (Fisch.) Bge. (Am B) under 100 mmol·L⁻¹ NaCl stress were treated with GB 0–40 mmol·L⁻¹. The rate, potential, and index of seed germination as well as the seedling vigor index and relative salt damage occurrence percentage to the plants were determined. The activities of SOD, CAT, POD, APX, GR and DHAR in the seedlings were analyzed.

  Result   Addition of GB 30 mmol·L⁻¹ to the salt containing medium increased the germination rate of Am H seeds by 159.07% and of Am B seeds by 167.01%, while reduced the relative rate of salt damage on Am H seedlings by 74.38% and on Am B seedlings by 76.18% in comparison to those without the addition. Under salt stress, the seedlings treated with GB 10–30 mmol·L⁻¹ raised on the SOD, CAT, POD, APX, GR and DHAR activities in varying degrees. In general, the activity increases were greater on seedlings of Am B than those of Am H.

  Conclusion   The addition of GB 30 mmol·L⁻¹ effectively ameliorated the adverse effects of the salt stress on the seeds and seedlings of A. membranaceus and more pronounced on Am B than on Am H.