The effect of cadmium sulphate (CdSO4) treatment on some metabolic events in sunflower (Helianthus annuus L.)

In this study, effects on Cd accumulations, amount of phytochelatin, total protein and nitric oxide levels in leaves, stem and root tissues were investigated under different cadmium sulphate (CdSO4) conditions. Tolerant and sensitive sunflower plants were determined by treatments of different cadmium sulphate (CdSO4) concentrations on 11 varieties of sunflower (Helianthus annuus L.). Meriç and Tarsan 1018 varieties as the most tolerant and most sensitive to Cd applications were decided to use our experiments. CdSO4 treatments (150 ?M, 200 ?M 250 ?M ve 300 ?M) were applied for 2 and 4 days to sunflower plants grown in Hoagland culture conditions for 15 days. Accumulation of Cd in leaf, stem and root tissues in both Meriç and Tarsan 1018 varieties treated with different concentrations of Cd, were observed to increase depending on the exposure time. Cd accumulation and amounts of phytochelatin were found to be lower in tolerant Meriç variety compared to sensitive Tarsan 1018 variety. It was observed that the total soluble protein amounts reduced after 2 and 4 days of Cd application in both varieties but in Tarsan 1018 variety this decrease was more obvious. For nitric oxide levels, there was an increase in Meriç variety depending on the concentration of the Cd treatment and in Tarsan 1018 variety there was a variation for all three tissues in the 2nd day and there was an increase in the 4th day. For all concentrations and both exposure times NO levels in tolerant Meriç variety were higher than those of sensitive Tarsan 1018 variety. In conclusion, Meric variety was considered as tolerant to Cd stress comparing to Tarsan 1018 variety, because it accumulated less Cd in leaves, stem and roots, produced less phytochelatin, decrease of the total protein was less and synthesised high levels of nitric oxide. KEY WORDS: Helianthus annuus, ayçiçeği, heavy metal stress, cadmium (Cd), phytochelatin, total soluble protein, nitric oxide