The toxicity and bioaccumulation of two heavy metals-lead (Pb) and cadmium (Cd)-in a semi-aquatic plant, Colocasia esculenta (L. Schott), from a synthetic heavy metal solution were studied. Young plants of equal size were grown hydroponically in shallow raceways containing Hoagland medium amended with 20, 40, and 60 mg l -1 of Pb and 2, 4, and 6 mg l -1 of Cd. The medium containing heavy metals was allowed to flow through the raceways with a change in influent heavy metal solution on every 5th day. The experiment was continued for 20 days. A set of control raceways-one comprised of nutrient medium with heavy metal supplements, devoid of plants, and another with the plants and nutrient medium having no metal supplement-was also simultaneously run. Chlorosis in the leaves was the prominent toxicity symptom observed due to Pb and Cd on the test plants. A significant decrease in the relative growth, biomass productivity, and total chlorophyll content were noticed in the plants with an increase in concentration of metal supplement in the solution and exposure time. Both metals accumulated to higher concentrations in the roots than in shoots, suggesting that the metals were bound to the root cells and their translocation to the leaves was limited. The results of the 20-day-long experiments indicate that from a phytoremediation perspective, C. esculenta is a promising plant species for remediation of wastewater polluted with lower concentrations of Pb and Cd.

The efficacy of chemical dips and different storage condition, alone and in combination were imposed in freshly harvested litchi fruit to investigate the changes of bio-chemical composition of fruits at regular interval for a certain period of storage. The pre-cooled litchi fruits after disinfectant were dipped for 60 seconds in lecithin (0.5% & 1%), Hot water, HCl (3%) with hot water, CaCl2 (1% & 2%), CaSO4 (1% & 2%), wax emulsion (5% & 10%), CaNO3 (0.5% & 1%), Chitosan (1% & 2%) and Kaolin (1% & 2%). The treated fruits were stored at room temperature as well as at 4°C & 90% R.H and the quality attributes were assessed at 2, 4, 6 and 8 days interval. Calcium nitrate @ 1% under refrigerated conditions recorded maximum ascorbic acid (54.50 mg/100g pulp), fruit firmness (1.75 kg cm-2) and the lowest acidity (0.42%). Total soluble solids (18.17°B), total sugar (11.27%) and polymeric colour retention with high anthocyanin content (48.94 mg/100g pulp) in peel was found in treated fruits with calcium chloride @1% at 4°C & 90% R.H even after 8 days of storage.

No abstract