study of sunflower plant response to cadmium and lead toxicity by usage of pgpr in a calcareous soil

abstract nowadays, soil pollution with heavy metals has become a major problem which their accumulation in plants can directly or indirectly influence on animals and humans life. lead and cadmium are poisonous metals, with increasing the amount of these metals in environmental pollution; they will be increased in food chain significantly. in this research, three levels of cadmium (0, 100 and 200 mg/kg), three levels of lead (0, 200 and 400 mg/kg) and three levels of native resistance bacteria inoculants (b0: control, b1: bacillus mycoides and b2: bacillus circulans ) were examined as a factorial experiment with randomized complete block design (rcbd) in three replications. then sunflower responses to cadmium and lead toxicity including: heavy metal and micronutrients concentration and their uptakes and finally dry matter weight of sunflower were evaluated in greenhouse condition. results showed that with increasing cadmium and lead concentration in soil, concentration of these elements in plant root and shoot increased significantly (p<0.05). therefore, cadmium showed a high ability of translocation from root to shoot. the highest translocation factor (tf) for cadmium which was equal to one occurred in all six treatments and for lead which was 0.716 observed in cd200pb400b2. the highest rate of uptake for cadmium and lead in root with use of native bacterial inoculants in cd100pb400b1 and cd0pb400b1with 260 and 481 g/pot and in shoot in cd200pb200b0 and cd0pb400b1 with 377 and 389 g/pot respectively. application of resistance and native pgpr improves uptaking rate of nutrient elements and it also helps to increase plant resistance in stress conditions.