Manganese tolerance and accumulation in six Mn hyperaccumulators or accumulators

Abstract

This study used hydroponics cultivation to investigate the manganese (Mn) accumulation and tolerance abilities of six species—Phytolacca americana L., Poa annua L., Comnyza canadensis L., Cynodon dactylon L., Polygonum hydropiper L., and Polygonum perfoliatum L. We found that P. perfoliatum, P. hydropiper, and P. americana were Mn-hyperaccumulators and that P. perforliatum have superior Mn accumulation and toleration abilities over the other five species. The Mn concentration within the shoots of P. perfoliatum reached as high as 18,342.3 mg kg−1. The root growth of P. perfoliatum was promoted under low-Mn treatments, but the growths of the five other species were inhibited by the Mn treatments and the damage intensified as Mn concentration increased. The biomass of P. perfoliatum was minimally affected by the Mn treatments. The chlorophyll (CHL), soluble protein (SP), and malondialdehyde (MDA) contents of P. perfoliatum were not adversely affected, but these parameters of the other five species showed significant (P < 0.05) deterioration from the control. By comparison among the six species, the hyperaccumulator P. perfoliatum was the most suitable species for bioremediation of Mn-polluted environments. However, the findings need further study in soil cultivation.