Differential Effects of Selenium and Trehalose on Growth, Nutritional Quality, and Antioxidant Properties of Mustard Sprouts

Mustard sprouts are rich in nutrients and have considerable potential as functional vegetables. In this study, we evaluated the effects of selenium, trehalose, and their combination on the growth and nutritional quality of mustard sprouts. Selenium and trehalose treatments reportedly enhanced the nutritional attributes of the sprouts. Selenium alone had the strongest growth-promoting effect, increasing edible fresh weight and plant height to 1.09- and 1.10-fold of the control, respectively. Both individual and combined treatments of selenium and trehalose enhanced nutrient accumulation and antioxidant capacity. Notably, selenium treatment alone increased the soluble sugar, soluble protein, ascorbic acid, flavonoid, and total phenolic contents to 1.09-, 1.23-, 1.06-, 1.29-, and 1.62-fold of the control, respectively. Trehalose alone and the combined selenium–trehalose treatment markedly increased total indolic glucosinolates accumulation, whereas selenium alone significantly reduced its content, and the combined treatment was especially advantageous in the accumulation of indolic glucosinolates. Collectively, selenium treatment alone effectively improves the nutritional quality and antioxidant capacity of mustard sprouts, while the application of Tre alone and the combined treatment promoted the accumulation of secondary metabolites, accompanied by the inhibition of plant growth and the decrease in photosynthetic pigment content, providing a basis for regulating their nutritional quality.