Effects of different exogenous selenium on Se accumulation, nutrition quality, elements uptake, and antioxidant response in the hyperaccumulation plant Cardamine violifolia

Cardamine violifolia (Brassicaceae) is a novel selenium(Se) hyperaccumulation plant with rich nutrients, and serves as a good source of special vegetables in Enshi, China. The present study aimed to investigate the effects of the application of selenate, selenite, and Se yeast (50-800 mg/L) on the growth, Se accumulation, nutrient uptake, and antioxidant response of C. violifolia. The results showed that the Se accumulation efficiency was selenate > selenite > Se yeast, the maximum Se concentration could achieve over 7000 mg/kg, and about 90% was organic Se. The major Se speciation found was mainly SeCys2 and the proportion of various Se species were affected by the Se forms and concentrations. Besides, the plant growth, nutrition quality indexes, element uptakes, and antioxidant responses indicated that 200 mg/L selenate was optimum for C. violifolia to accumulate Se without much impacts, while to obtain more proportion of organic Se, 200 mg/L selenite might be a better choice.