Interactions between chromate and sulfate affect growth, photosynthesis and ultrastructure in Brassica juncea (l.) czern.

The use of plants is a promising solution to remediate chromate-contaminated sites. At the present knowledge, plants seem to take up chromate by means of the sulfate transport system. Therefore, to better understand the physiological effects of sulfate and chromate interactions, Brassica juncea plants were grown under different chromate and sulfate availability. The growth of B. juncea plants was affected by chromate 0.2 mM, regardless of sulfur availability. No significant change was observed in Chlorophyll a content, while the levels of transpiration, stomatal conductance and net CO2 assimilation were strongly reduced after plant exposure to chromate. In particular, in Cr-treated plants the decrease of stomatal conductance was ascribed to the alteration of leaf cell ultrastructure, and it was mainly responsible for the photosynthesis decline, which in turn was the cause of the reduction of fresh weight biomass.