The investigation of exogenous application of organic carboxylic acids on some biochemical parameters and Cd and Pb absorption by canola seedlings

Regarding to excess entry of heavy metals to the natural resources and the importance of heavy metals removal from the environment, in this investigation, the effect of some organic acid treatment on cadmium and lead absorption was studied on one week Brassica napus seedlings. Canola seeds were cultured in Petri dishes containing 10 mL of 100 μM CdCl2 or 100 μM PbCl2 and some organic carboxylic acids including 50 μM citrate, 1 μM oxalate, 50 μM fumarate or 300 μM histidine. To study the role of these organic acids on abbreviation of heavy metal stress, some biochemical and growth parameters including the content of total chlorophyll, carotenoids, hydrogen peroxide, malondialdehyde and dry weight, was also investigated in 7 days canola seedlings under Cd and Pb stress. Although organic carboxylic acid treatment increased Cd and Pb absorption by canola seedlings, there was also an increase in content of total chlorophyll, carotenoids and dry weigh in seedlings treated by carboxylic acids. Cadmium and lead stress caused the higher content of hydrogen peroxide but carboxylic acid application decreased the content of malondialdehyde and hydrogen peroxide in seedlings under heavy metals stress. Based on the results, it seems that the application of some organic carboxylic acids not only improve remediation capability of Cd and Pb by canola seedlings, but also has positive effects on abbreviation of Cd and Pb toxicity in canola seedlings.