IMPACT OF FOLIAR APPLICATION OF Α-TOCOPHEROL ON GROWTH PARAMETERS, DNA INTEGRITY LOSS, CELL PROLIFERATION INCREASE, NUCLEAR MORPHOLOGY AND CHROMOSOMAL ALTERATIONS OF FABA BEAN CULTIVARS UNDER CADMIUM STRESS

In the present study, we attempted to clarify the mechanism that might be involved in the ameliorative effects of alpha-tocopherol on faba bean plants grown under different Cd levels. The effect of alpha tocopherol on growth parameters, photosynthetic pigments, micronucleus formation, DNA integrity loss, cell proliferation increase, nuclear morphology and chromosomal alterations. These were studied in plants grown in a nutrient solution supplemented with different concentrations of Cd (0 or 150 mu mol/l) and sprayed with alpha-tocopherol at concentrations of 0, 50 and 100 mg/l. Heavy metal stress caused an increase in chlorophyll a and b. Cytogenetic analysis showed that Cd could cause significant micronucleus formation and the appearance of chromosomal abnormalities affecting the structure and number of chromosomes in the root meristems of the bean. The genotoxic effect of Cd is caused by the production of ROS. It should be noted that the combination of tocopherol and Cd reduced the toxic effect of this stress at cellular level. Application of alpha-tocopherol helping to reduce oxidative damage and develop tolerance to heavy metal stress in alpha-tocopherol-treated bean plants. This alpha-tocopherol-induced increase in tolerance to heavy metal stress was evidenced by improvements in photosynthetic activity. The results show that treatment with alpha-tocopherol reduced the adverse effects of Cd stress on bean plants.