Open Access

ARTICLE

Exogenous Glycine Betaine Reduces Drought Damage by Mediating Osmotic Adjustment and Enhancing Antioxidant Defense in Phoebe hunanensis

by Yujie Yang¹, Chengshi Huang², Zuguo Ge³, Bengeng Zhou⁴, Guangju Su⁴, Chunling Liu⁴, Yongjun Fei^1,*

1 College of Horticulture and Gardening, Yangtze University, Jingzhou, 434025, China
2 Economics and Management School, Yangtze University, Jingzhou, 434025, China
3 Chenglong Municipal Garden Design and Research Co. Ltd., Jingzhou, 434020, China
4 Shuangzhu Forest Farm, Shiyan, 442300, China

* Corresponding Author: Yongjun Fei. Email:

(This article belongs to the Special Issue: Plant Ecophysiology: Recent Trends and Advancements)

Phyton-International Journal of Experimental Botany 2022, 91(1), 129-148. https://doi.org/10.32604/phyton.2022.016704

Received 18 March 2021; Accepted 19 May 2021; Issue published 16 August 2021

Abstract

Drought stress negatively impacts growth and physiological processes in plants. The foliar application of glycine betaine (GB) is an effective and low-cost approach to improve the drought tolerance of trees. This study examined the effect of exogenously applied GB on the cell membrane permeability, osmotic adjustment, and antioxidant enzyme activities of Phoebe hunanensis Hand.-Mazz under drought stress. Two levels (0 and 800 mL) of water irrigation were tested under different applied GB concentrations (0, 50, 100, and 200 mM). Drought stress decreased the relative water content by 58.5% while increased the electric conductivity, malondialdehyde, proline, soluble proteins, soluble sugars, and antioxidant enzyme activities (superoxide dismutase, catalase, peroxidase) by up to 62.9%, 42.4%, 87.0%, 19.1%, 60.5%, 68.3%, 71.7%, and 83.8%, respectively, on the 25^th day. The foliar application of GB, especially at 100 mM, increased the relative water content of P. hunanensis leaves under drought stress. The concentration of GB from 50 to 100 mM effectively alleviated the improvement of cell membrane permeability and inhibited the accumulation of membrane lipid peroxidation products. Under drought stress, the concentrations of proline, soluble proteins, and soluble sugars in the leaves of P. hunanensis increased as the applied GB concentration was increased and the water stress time was prolonged. Exogenously applied GB decreased oxidative stress and improved antioxidant enzyme activities as compared with treatments without GB application. Furthermore, the physiological and biochemical indexes of P. hunanensis showed a certain dose effect on exogenous GB concentration. These results suggest that GB helps maintain the drought tolerance of P. hunanensis.

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