Phytostabilization of mine waste: growth and physiological responses of Vigna unguiculata (L.) Walp.

Greenhouse experiments were carried out for phytoremediation of the Pb/Zn abandoned tailings (pH 3.2 and high metal content) of Rampura-Agucha Mines, Rajasthan. Vigna unguiculata (L.) Walp. (cowpea) was chosen as a test crop. On unamended tailings, the seeds of the test plant showed no germination. The tailing was amended with lime (3% on weight basis), 3% lime + NPK (diammonium phosphate at 60 kg/ha, muriate of potash at 40 kg/ ha) and 3% lime + FYM at 15 t/ha and used for experiments. Quantification of various parameters viz. shoot-root length, shoot-root dry weight, chlorophyll contents (a', 'b' and total) and peroxidase activity of test crop revealed T+ S + 3% lime + NPK to be the most suitable amelioration followed by FYM. The above treatments helped in improving the growth and productivity of the test plants by providing a favorable environment.

Interactive effects of Zn, Pb and Cd in barley.

The effects of different concentrations of Zn, Pb and Cd singly as well as in the combination of zinc-lead, zinc-cadmium and lead-cadmium on the shoot root length and dry mass as well as chlorophyll contents of barley plants during early seedling growth were studied. The effects of different concentrations of Zn x Pb and Pb x Cd in combinations showed a synergistic relationship, while at higher concentrations the relationship was antagonistic. Lower as well as higher Zn x Cd concentrations showed antagonistic effects.

Influence of aluminium on growth and water relations of cowpea.

The effect of aluminium on shoot-root fresh weight and water relations [water potential (psiw), osmotic potential (psis), turgor potential (psip), and relative water content (RWC)] was studied in cowpea. The 3 microg g(-1) Al showed slight enhancement in psiw and psip in test plants. Concentrations beyond 3 microg g(-1) Al significantly decreased psiw (less negative) and psip. Relative water content (RWC) vis a vis the fresh weight was also affected adversely at higher Al concentrations.

Phytostabilisation of tailing dams: a quantification of physiological and biological responses in plants.

Effect of unamended and variously amended tailings of Rajpura-Dariba mines, Udaipur, India was studied on certain physiological and biochemical responses of plants. Plants grown in unamended tailings, showed reduction in shoot-root length, shoot-root dry weight, chlorophyll content and an increase in total phenol contents and peroxidase activity. Ameliorations resulted in an increase in growth and chlorophyll contents, a decrease in total phenol contents and reduction in peroxidase activity in the test plants.

Growth and cadmium uptake in barley under cadmium stress.

Effect of various additions of cadmium (5 to 3125 microg g(-1) air dried soil) was studied on growth and Cd uptake in barley grown in pots containing two soil types- a loamy sand and a sandy loam, during different stages of growth. While lower doses (5 to 25 microg g(-1)) led to an increase, the higher doses resulted in a substantial decrease in barley growth. The plant Cd content increased with an increase in soil applied Cd. A decrease in translocation ratio prevailed at higher soil applied Cd, indicating the existence of an exclusion mechanism.