Ultrasonic Treatment Enhances Germination and Affects Antioxidant Gene Expression in Soybean (Glycine max L. Merr)

Abstract

Ultrasound technology has been recently used to enhance and increase seed germination with no negative effect on seedling development. This study investigated the effects of ultrasound exposure for 10, 20, and 30 min on seed germination, seedling growth, and gene expression of three soybean varieties grown under glasshouse conditions. Ultrasonic treatments showed different effects on most of the studied traits compared with the untreated controls. Ultrasonic exposure increased germination percentage, root and shoot lengths, seedling dry matter, and vigor index of the three soybean varieties. Antioxidant gene expression was examined in the seedling tissues and indicated a significant stimulatory effect of ultrasonication on catalase and superoxide dismutase antioxidant gene expression. Scanning electron microscopy results showed multiple changes in soybean varieties. Seed coat rupturing appeared as pores and cracks on the waved seed coat and possibly increased seed germination. Soybean varieties revealed different abilities to germinate, grow, and develop, as well as different antioxidant gene expression in response to ultrasound treatments. In light of the results obtained, ultrasonication can be widely used to include other crops that face serious challenges in germination.