The Role of Trichoderma harzianum in Cadmium Biosorption of Barley (Hordeum vulgare L.) in a Contaminated Soil

Soil pollution by heavy metals due to industrial activities، factories، fertilizers and pesticides is an environmental problem which threatens public health. Therefore، it is necessary to find some solutions to ameliorate the negative effects of heavy metals in soil. Accordingly، an experiment was designed to evaluate the effect of Trichoderma harzianum fungi as a cadmium (Cd) biosorbent in barley (cv. Sahra) cultivated on a Cd contaminated soil. Treatments were arranged in factorial experiment based a completely randomized design and were replicated three times. Experimental factors consisted of T. harzianum fungi at two levels (inoculated and non-inoculated control) and four levels of cadmium nitrate (0، 50، 100 and 150 mg L-1). Results indicated that Trichoderma inoculation increased barley biological yield (by 36%) as compared to those in non-inoculated plants. Where Cd was added، both Cd amount in soil and Cd bioaccumulation in plants markedly increased. The Cd content in barley root varied from 0. 02 mg kg-1 in non-contaminated soil to 688. 2 mg kg-1 in 150 mg L-1 contaminated soil. Furthermore، the presence of the Trichoderma significantly increased the Cd uptake in plant roots (from 53 to 96%) in moderate to high levels of cadmium contamination when compared to those in non-inoculated plants. The maximum Cd phytoextraction (5. 260 mg per pot) resulted in Trichoderma inoculated plants and at maximum rate of Cd which was 100% greater than untreated plants. In conclusion، it seems that inoculation of Trichoderma with barley plants could be an optimum option to remediate the Cd contaminated soils.