Effect of mycorrhizal symbiosis on growth, some physiological parameters and cadmium accumulation in black seed (Nigella sativa L.)

The environmental changes by human activities lead to contamination of natural ecosystems and agricultural lands to heavy metals such as cadmium (Cd), which enumerates the most important environmental pollutants. This experiment was conducted for study of cadmium and mycorrhizal symbiosis effects on growth and physiological parameters as well as cadmium accumulation in Black seed (Nigella sativa L.). The experiment was conducted as factorial in a completely randomized design with three replications in green house conditions. Cadmium chloride with four different concentrations (0, 250, 750 and 2500 &muM) in absence and presence of mycorrhizal fungi Glomus intraradices were used. Seedlings in the four leave stage treated 3 times in week with CdCl2 and after 45 days were taken for measurement of morphological and physiological parameters. Results showed that cadmium lead to significant decrease of growth parameters whereas proline and reducing sugar’s contents was increased with cadmium chloride treatments. Mycorrhizal symbiosis leads to significant increase of growth parameters. In mycorrhizal plants Proline content, reducing sugar content and cadmium accumulation were significantly higher than non-mycorrhizal plants. The results showed that the cadmium translocated from root to shoot in plants colonized by symbiotic fungi was lower than non-symbiotic plants. Therefore, despite the cadmium absorption increase in mycorrhizal plants, reduced translocation rates to the shoot.