Open Access

ARTICLE

The Physiological and Molecular Responses of Exogenous Selenium to Selenium Content and Fruit Quality in Walnut

by Mufang Sun¹, Xinran Hui², Cuiling Tong³, Longyi Yuan², Dejian Zhang^1,2,*

1 Xinyang Agriculture and Forestry University, Xinyang, 464000, China
2 Tibet Plateau Walnut Industry Research Institute, Yangtze University, College of Horticulture and Gardening, Jingzhou, 434025, China
3 Jingzhou Institute of Technology, Jingzhou, 434025, China

* Corresponding Author: Dejian Zhang. Email:

(This article belongs to the Special Issue: Integrating Agronomy and Plant Physiology for Improving Crop Production)

Phyton-International Journal of Experimental Botany 2023, 92(3), 851-860. https://doi.org/10.32604/phyton.2022.025147

Received 24 June 2022; Accepted 01 September 2022; Issue published 29 November 2022

Abstract

To study the effect of exogenous selenium on fruit quality in walnut (Juglans regia L.), 8-year-old walnut (Qingxiang) was taken as the research object. In the fruit expansion stage, 300 mg/L of sodium selenate, yeast selenium and sodium selenite solutions were applied on the leaf of walnut, and the selenium levels in leaves, pericarp and kernel were determined at the ripening stage. The fruit quality, mineral nutrient content, antioxidant enzyme activity, and related genes’ expression were analyzed. The results showed that the three exogenous selenium increased the selenium levels in leaves, pericarp and kernel of walnut. They also significantly increased fruit and kernel weights, and kernel linoleic acid, but markedly decreased kernel crude fat and saturated fatty acid. Selenium spraying promoted the absorption of mineral nutrients such as potassium and zinc, but inhibited the absorption of calcium, and had no significant effect on iron and magnesium in the kernel. Three exogenous selenium increased the activities of superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT) significantly in the kernel. Except for sodium selenate treatment significantly reduced malondialdehyde (MDA) content in the kernel, the other two selenium sources treatments had no significant effect on MDA and hydrogen peroxide (H₂O₂) levels. They also increased the expression of JrCu/Zn-SOD, Jr2-Cys POD, JrCyt-APX and JrCAT in kernel, to different extents. These implies that, in the walnut fruit enlargement period, the foliar spraying selenium could increase the selenium content of walnut, affect the mineral nutrient absorption, improve the antioxidant capacity and related genes’ expression, and reduce the degree of peroxide, and then improve the quality of fruit. Furthermore, yeast selenium showed the comprehensive effect of the best.

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Keywords

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