Chromium(VI) bioremediation by aquatic macrophyte Callitriche cophocarpa Sendtn.

Callitriche cophocarpa (water-starwort)--aquatic widespread macrophyte--was found to be an excellent chromium accumulator. The plants were exposed to various chromium(VI) concentration ranging from 50 to 700 microM in a hydroponic culture up to ca. 3 weeks. Physiological conditions of shoots were monitored via measuring potential photosynthesis quantum efficiency (F(v)/F(m)) and photosynthetic pigment contents. Additionally, the structure of leaves was analyzed using optical and atomic force microscopy (AFM). It has been shown that plants grown in 50 microM Cr(VI) solution exhibited photosynthetic activity and shoot and leaf morphology similar to control plants. Moreover, at the same time the average Cr concentration in their shoots reached about 470 mg kg(-1)d.w. after 10d and up to 1000 mg kg(-1)d.w. after 3 weeks of culture while in control plants did not exceed a few mgkg(-1)d.w. Our results point to Callitriche cophocarpa as a very promising species to be used in the investigation of chromium(VI) phytoremediation mechanisms as well as a good candidate for wastewaters remediation purpose.