Boron tolerance and accumulation potential of four salt-tolerant plant species

Boron (B) is an essential element for plants, but excess B is phytotoxic. Since excess B often occurs along with high salinity in the environment, the purposes of the experiments are to screen plants that tolerate both excess B and high salinity for the remediation of B-contaminated saline water or soils. Here we tested the capacities of B tolerance and accumulation of four salt-tolerant plant species, Tripolium pannonicum, Suaeda glauca, Iris wilsonii, and Puccinellia tenuiflora using hydroponic culture systems, and compared their potential for application in phytoremediation. The maximum B supply concentrations for the survival of T. pannonicum, S. glauca, I. wilsonii, and P. tenuiflora are 40, 250, 700, and 300 mg/L, respectively. The maximum B concentrations in the shoot tissue of these plants are 0.45, 2.48, 15.21, and 8.03 mg/g DW, and in the root are 0.23, 0.70, 6.69, and 2.63 mg/g DW, respectively. Our results suggest that S. glauca, I. wilsonii, and P. tenuiflora are capable of tolerating and accumulating high levels of B, and I. wilsonii is a most promising candidate for the remediation of B-contaminated sites. This study will provide evidence in support of our future pilot studies (e.g., constructed wetlands) on the phytoremediation of B-contaminated water and soil.