Amino acid promotes selenium uptake in medicinal plant Plantago asiatica

The medicinal plant, Plantago asiatica have high selenium (Se) accumulation ability but is considered lower compared to other Se-hyperaccumulators. In this experiment, we evaluated the effects of different amino acid concentrations (600, 900, 1200, and 1500-fold dilutions) on the growth and Se uptake in P. asiatica for possible improvement of Se accumulation ability and medicinal value of P. asiatica. The 600, 900, and 1200-fold amino acid dilutions increased the root and shoot biomass of P. asiatica. Additionally, the photosynthetic pigments contents (chlorophyll a, chlorophyll b, and total chlorophyll) and antioxidant enzymes activities (superoxide dismutase, peroxidase, and catalase) of P. asiatica were increased by the different amino acid concentrations. However, these amino acid concentrations reduced the soluble protein content of P. asiatica to some extent. The Se content and extraction from P. asiatica were also enhanced and had a quadratic polynomial regression relationship with the Se extraction tissues and their Se contents. In addition, there were significant correlations between the biomass of Se extraction tissues and their Se contents. Our findings indicate that various amino acid concentrations promote growth and Se uptake in P. asiatica, but 900-fold amino acid dilution is the best concentration for enhancing Se accumulation ability in P. asiatica shoots.