Nitrilotriacetate- and citric acid-assisted phytoextraction of cadmium by Indian mustard (Brassica juncea (L.) Czernj, Brassicaceae).
ABSTRACT In a pot experiment the effects of nitrilotriacetate (NTA) and citric acid applications on Cd extractibility from soil as well as on its uptake and accumulation by Indian mustard (Brassica juncea) were investigated. Plants were grown in a sandy soil with added CdS at four levels ranging from 50 to 200 mg Cd kg(-1) soil. After 30 days of growth, pots were amended with NTA or citric acid at 10 and 20 mmol kg(-1). Control pots were not treated with chelates. Harvest of plants was performed immediately before and one week after chelate addition. Soil water-, NH(4)NO(3)- and EDTA-extractable Cd fractions increased constantly with both increasing soil metal application and chelate concentration. Shoot dry weights did not suffer significant reductions with increasing Cd addition to the soil except for both NTA treatments in which at 200 mg Cd kg(-1) a 30% decrease in dry matter was observed. Generally, following NTA and citric acid amendments, Cd concentration in shoots increased with soil Cd level. However, due to Cd toxicity, at the highest metal application rate both NTA treatments lowered Cd concentration in the above-ground parts. Compared to the control, at 10 mmol kg(-1) citric acid did not change Cd concentration in shoots, whereas NTA-treated plants showed an about 2-fold increase. The addition of chelates at 20 mmol kg(-1) further enhanced Cd concentration in shoots up to 718 and 560 microg g(-1) dry weight in the NTA and citrate treatments, respectively.
Article: Effect of easily biodegradable amendments on heavy metal solubilization and accumulation in technical crops-a field trial[show abstract] [hide abstract]
ABSTRACT: Heavy-metal soil pollution is a common environmental problem all over the world. In the induced phytoextrac-tion process plants can transport and translocate to their above-ground tissues significant concentration of contaminants. Since some heavy metals are mostly presented in non-soluble state, the application of chelating agents is needed. In this study we introduced into the rhizosphere of maize (var. Kneja 530) and sunflower (var. Favorit) plants 1 and 5 mmol l –1 of EDDS and NTA, and 5 g kg –1 of nutrients to enhance the accumulated concentrations of cadmium, lead and zinc. The fraction of CaCl 2 -extractable metals increased incrementing the concentration of chelates. This was clearly pronounced for all the metals in the treatments with NTA and for Pb in those with EDDS. Generally, under all the experimental conditions the accumulated heavy-metal concentrations were found to be significantly higher than in the control. Thus, in the case of higher concentration of NTA and EDDS, the accumulated Cd in the leaves of sunflower was found to be threefold higher. The highest accumulation of Pb in the leaves of maize was observed when nutrients were added (62 mg kg –1). On the other hand, negative effects of the used chelating agents on soil bacteria and fungi at plant harvest were not observed. Moreover, when nutrients were added, the number of studied microorganisms significantly increased.