Sodium selenate stimulates growth and photosynthetic pigments in sweet potato plantlets in vitro

Selenium deficiency is a widespread nutritional problem worldwide, and biofortification has been proposed as a strategy to increase selenium intake through food crops. This study evaluated the effects of sodium selenate on growth, photosynthetic pigments, and selenium accumulation in sweet potato (Ipomoea batatas) plantlets micropropagated in vitro. Explants were cultured in hormone-free Murashige and Skoog medium supplemented with 0, 5, 10, 15, 20, and 25 µM sodium selenate. Plantlets grown with 5.0 µM sodium selenate showed the highest values for growth-related traits, including number of leaves, shoot length, root length, and dry biomass. Photosynthetic pigments were also enhanced at low selenium concentrations, with maximum chlorophyll and carotenoid contents observed at 5.0 µM. In contrast, higher selenium concentrations reduced plant growth and pigment accumulation, indicating phytotoxic effects. Selenium accumulation increased progressively with increasing sodium selenate concentration, reaching the highest levels at 25.0 µM. These findings indicate that 5.0 µM sodium selenate is suitable for in vitro propagation of sweet potato plantlets, whereas higher concentrations may be useful for initiating selenium biofortification strategies.