Phytoremediation of Cd and Ni by mustard (Brassica juncea L.) as affected by chelating agents and bioinoculants
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Date
2014
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Publisher
CCSHAU
Abstract
Laboratory and screen house studies were carried out to evaluate the effect of chelating agent
(EDTA @ 2 mmol kg-1 (5 split doses), FYM, vermicompost and microbial inoculants (Azotobacter and
Pseudomonas, Bio-mix) on the phytoremediation of Indian mustard from Cd (100 μg g-1) and Ni (100
μg g-1) enriched sandy loam soil. Fractionation studies of Cd and Ni were also carried out in post
harvest soil samples to investigate the contribution of different fractions of Cd and Ni accumulation by
the Indian mustard. Present studies showed that FYM and vermicompost led to higher biomass
production as compared to unamended soil. The bioinoculants also contributed in augmentation of
biomass production but not significantly. The EDTA led to decrease in biomass as compared to FYM
and vermicompost. The Cd and Ni concentration increased significantly in Brassica juncea with the
application of EDTA. The application of FYM and vermicompost increased concentration of Cd and
Ni. The seed treatment with bioinoculants was helpful in increasing concentration but was not much
effective. The highest concentration of Cd and Ni was recorded in EDTA treatment. The concentration
of Cd and Ni was higher in root as compared to shoot. Among all the treatment combinations,
vermicompost with bioinoculants treatment combination led to higher uptake of Cd and Ni. The EDTA
and FYM also increased uptake of Cd and Ni but it was very less as compared to vermicompost. Postharvest
DTPA extractable Cd and Ni in soil were low in the treatments EDTA and EDTA with
microbial inoculants as the availability of these metals were increased by EDTA and microbial
inoculants to the growing plants, thereby increasing concentration in plant biomass. Fractionation
studies of post harvest soil samples showed that application of EDTA led to shift in the distribution of
Cd and Ni from more bound to more soluble forms. The bacterial count studies showed that application
of FYM and vermicompost in Cd and Ni enriched soil increased counts of Azotobacter and
Pseudomonas. The application of EDTA helped in increasing bacterial counts. The bacterial counts
also increased with increasing time. The results suggested that vermicompost combined with
bioinoculants is best for increasing uptake of Cd and Ni and also EDTA and FYM as implications were
helpful in phytoremediation of these metals from polluted soils, however, there is a strong need for
further investigation in this aspect, with hyperaccumulator genomics.
Description
Keywords
Planting, Vegetative propagation, Farmyard manure, Fractionation, Concentrates, Brassica juncea, Vermicomposting, Bacteria, Application methods, Drying