Dose dependent phytotoxic effects of Cd, Ni, and Cu on cauliflower in vitro

This study was carried out to evaluate the effects of cadmium (Cd), nickel (Ni), and copper (Cu), which are significant components of industrial pollution, on germination and early seedling development in cauliflower (Brassica oleracea var. botrytis). Experiments were carried out in MS nutrient medium using heavy metal doses of 0 (control), 100, 300, and 500 µM under in vitro conditions. Morphological and physiological parameters such as germination percentage, germination index, mean germination time, shoot-root length, and fresh and dry weight were examined. The results showed that the phytotoxic effect varied depending on the metal type and dose. Cd particularly suppressed germination at high doses (42.00% at Cd-500). Cu showed toxic effects even at low doses, with germination values varying between 50.00% and 53.00% between treatments. Ni, on the other hand, showed a stimulating effect on some parameters, such as root length (50.73 mm at Ni-100), at low and medium doses. The longest shoot length was recorded in the control group (42.40 mm), while significant reductions were observed at higher metal doses. Correlation analysis revealed positive relationships between growth parameters and a negative relationship between root dry weight and germination measurements. PCA showed that most of the variance was concentrated in the first three components, which together explained 73.4% of the total variation.