M. Raychaudhuri, S.K. Rautaray and
ICAR – Indian Institute of Water
Management, Chandrasekharpur, Bhubaneswar, Odisha - 751 023, India
Author Email :
Aim: Vegetables grown
in cadmium contaminated soils accumulate cadmium in their tissues and are
risky for consumption. The aim of the study was to get an insight into the
effect of different levels of cadmium in soil, on accumulation in different
plant parts of okra and its effect on overall growth, biomass production and
photosynthesis rate so that suitable management option is explored to produce
safe vegetable in cadmium contaminated soils.
Methodology: The study was
conducted in replicated pots with three soil pH (5.46, 6.54 and 7.45)
attained through addition of CaCO3 as main treatment and four Cd
levels viz., 0, 3, 6 and 9 mg kg-1 of soil as
sub-treatment. Okra (Abelmoschus esculentus) was taken as the test
crop. The experiment was conducted in a net house.
Results: The Cd
concentrations were minimum in fruits (0.54, 0.31 and 0.14 mg kg-1)
and higher in leaves at acidic pH (5.5), while in soil limed to slightly
acidic (6.5) and alkaline pH (7.5) roots retained maximum Cd among plant
parts. Net photosynthesis and biomass production decreased significantly with
higher Cd doses at acidic pH (5.5). The rate of decline in net photosynthesis
was lesser at higher soil pH. The transfer factors decreased with increase in
soil pH. The DTPA extractable soil Cd decreased from 8.5 to 2% when soil pH
increased rendering the Cd less available for plant uptake.
Interpretation: Liming can be an
effective ameliorative measure to mitigate Cd toxicity in acidic soils and
can ensure safe consumption. Lowest accumulation of cadmium in fruit part
suggests okra to be a potential vegetable crop for Cd polluted soils.
Key words: Metal contaminant, Net photosynthesis, Soil pH, Transfer
factor, Translocation factor