Selenium accumulation characteristics of Cyphomandra betacea (Solanum betaceum) seedlings.

Abstract

A pot experiment was conducted to study the selenium (Se) accumulation characteristics and the tolerance of Cyphomandra betacea (Solanum betaceum) seedlings under different soil Se concentrations. The 5mg/kg soil Se concentration increased the C. betacea seedling biomass and photosynthetic pigment contents (chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid), whereas the other soil Se concentrations (10, 25, and 50mg/kg) inhibited seedling growth. Increases in the soil Se concentrations tended to decrease the superoxide dismutase activity and soluble protein content, but had the opposite effect on the peroxidase and catalase activities. The 5, 10, and 25mg/kg soil Se concentrations decreased the DNA methylation levels of C. betacea seedlings because of an increase in demethylation patterns (versus 0mg/kg), whereas the 50mg/kg soil Se concentration increased the DNA methylation levels because of an increase in hypermethylation patterns (versus 0mg/kg). Increases in the soil Se concentrations were accompanied by an increasing trend in the Se content of C. betacea seedlings. Moreover, the amount of Se extracted by the shoots was highest for the 25mg/kg soil Se concentration. Therefore, C. betacea may be able to accumulate relatively large amounts of Se and its growth may be promoted in 5mg/kg soil Se.