Comparative accounts of chromium accumulation in three ferns under hydroponic system

摘要

Hydroponic experiments were carried out to demonstrate the chromium bioaccumulation potential of three ferns viz. Diplazium esculentum (Retz.) Sw., Pteris cretica L. and Polystichum squarossum (D. Don) J. Sm. Plants were exposed to seven levels of Cr (0, 25, 50, 100, 300, 600 and 100 μg ml~(-1)) for 10 days. All three test species accumulated significant Cr content in comparison to control. The result showed the increasing trends in fresh biomass (25-30%) up to 600 μg ml~(-1) concentration in P. cretica and P. squarossum. Although, D. esculentum showed necrosis even after 1 day exposure; necrosed biomass contained significant Cr than control but significant decrease in chlorophyll and carotenoid content indicates its least tolerance capacity. It has also been revealed that chlorophyll content was not affected by Cr exposure up to 300 μg ml~(-1) concentrations in P. cretica and P. squarossum and the carotenoid content showed the significant increase of 35 to 74% at higher dose from 300 and 1000 μg ml~(-1) in comparison to the control. Therefore, it has been observed that P. cretica and P. sqarossum are new Cr hyperaccumulator with efficient tolerance capacity. It also revealed that P. cretica has highest tolerance capacity to Cr ions amongst the three test species which often grows rapidly, densely and easily adapt to artificial cultivation and can be exploited for treatment of tannery and other Cr contaminated wastelands.