Effects of brassinolide on cadmium accumulation and growth of emerged accumulator plant Nasturtium officinale.

To assess the effects of brassinolide (BR) on the growth and phytoremediation ability of cadmium (Cd) accumulator plants, different BR concentrations were applied to emerged accumulator plant Nasturtium officinale growing in Cd-contaminated soil. Brassinolide application increased the biomass, photosynthetic pigment content, and antioxidant enzyme activity of N. officinale. When N. officinale was treated with 1.5 mg L−1 of BR, the highest shoot biomass was obtained, recording an increase of 26.06%, compared to the control. In addition, BR treatment decreased the Cd contents in the shoots of N. officinale, and the BR concentrations of 0.5, 1.0, 1.5, and 2.0 mg L−1 decreased the Cd content in shoots by 10.49%, 12.11%, 20.13%, and 17.23%, respectively, compared to the control. Brassinolide treatment also slightly inhibited the transportation of Cd from the roots to shoots. The findings revealed that BR had no significant effects on the Cd extraction amounts by stems, leaves, and shoots of N. officinale. However, BR promoted the growth of N. officinale and inhibited the Cd uptakes in the above-ground part of N. officinale. Thus, N. officinale could be used as a wild vegetable in the Cd-contaminated soil, although not suitable for phytoextraction as an accumulator plant. [ABSTRACT FROM AUTHOR]