Combined effect of Cr-toxicity and temperature rise on physiological and biochemical responses of Atriplex halimus L.

An experiment was conducted to evaluate the combined effect of temperature (26 and 30 degrees C) and Cr toxicity (0, 100 and 1000 mu M Cr) on growth, photosynthesis, water content, Cr and nutrients uptake and translocation. The role of antioxidative enzyme towards stresses tolerance was also investigated. Results showed that the maximum relative growth rate and leaf area per plant of Atriplex halimus L. were recorded at 100 mu M Cr and 26 degrees C. However, presence of Cr reduced net photosynthetic and stomatal conductance rates. Overall, temperature rise enhanced the toxic effect of Cr by reducing growth and photosynthesis and inducing antioxidant enzymes activities. Furthermore, temperature rise increased nutrient uptake, as well as nutrient translocation to above- ground tissues; while it diminished Cr translocation. Finally, roots were the main sink for Cr accumulation in A. halimus. At 1000 mu M Cr, root Cr concentrations reached 7.2 and 9.1 mg g(-1) at 26 and 30 degrees C, respectively; while shoot Cr concentrations were 0.45 and 0.44 mg g(-1) (26 and 30 degrees C, respectively). The high Cr-accumulation in roots suggests that A. halimus presents a great potential for phytoremediation, especially phytostabilisation of Cr contaminated soils.