P. Sundaramoorthy

Chromium stress in paddy: (i) Nutrient status of paddy under chromium stress; (ii) Phytoremediation of chromium by aquatic and terrestrial weeds

A field experiment was conducted with paddy (Oryza sativa L.) irrigated with different concentrations (Control, 2.5, 5, 10, 25, 50, 75, 100 and 200 mg/l) of chromium. The changes in growth, yield, nutrient content and chromium accumulation in the paddy are reported. The growth of shoot, root, total leaf area, fresh weight, dry weight and yield of the paddy gradually decreased with increasing Cr concentration. Similarly, the uptake of macronutrients (N, P, K) and micronutrients (Mn, Cu, Zn, Fe) were also gradually decreased. However, the chromium accumulation gradually increased with the increasing concentrations of chromium. Among the aquatic plants tested, Eicchornia crassipes showed better performance in accumulating higher amount of chromium. Similarly, certain grasses and weeds such as Cyperus rotundus, Cyperus kylinga, Marselia quadrifolia and Ludwigia parvifloria were used for the phytoremediation of chromium polluted soil. Among them, Cyperus rotundus accumulated higher amount of chromium than the other plants tested.

Chromium stress induced alterations in biochemical and enzyme metabolism in aquatic and terrestrial plants.

Water is seriously polluted by the discharge of various industrial wastewater containing heavy metals. Among them, chromium is considered to be toxic to living organisms and it is released mostly from tanneries. The chromium-contaminated water is discharged into nearby water bodies and it affects both aquatic and terrestrial plants. So the present experiment was conducted with an aquatic plant, water lettuce (Pistia stratiotes L.) and a terrestrial plant soybean (Glycine max L. Merr.). They were treated with different concentrations (0, 5, 10, 25, 50, 100 and 200mg/L) of potassium dichromate solution. The biochemical parameters such as total chlorophyll, carotenoid, protein and amino acid content and the enzymatic activities like catalase and peroxidase were estimated. The accumulation of chromium was also analysed in both the plants. All the biochemical contents and enzyme activities of water lettuce and soybean seedlings showed a great variation with respect to the increase in chromium concentrations. The accumulation of chromium increased gradually with the increase of chromium concentrations. Total inhibition of all the parameters were observed at 300 mg/L chromium concentration. The terrestrial plant soybean was sensitive than the aquatic plant water lettuce towards chromium stress.

Role of Organic Amendments in Sustainable Agriculture

Organic farming is one type of sustainable farming. It has potential, especially for farms that still rely on traditional and extensive agricultural methods. Organic farming can provide quality food without adversely affecting the soil’s health and the environment; however, a concern is whether large-scale organic farming will produce enough food for India’s large population. The past decade’s increases in agricultural yields would have been impossible without mineral fertilizer. After the green revolution, the mineral fertilizer usage is progressively increased but yet not to be achieved the expected yield. Until now, insufficient attention has been paid to the adverse effects on the soil and the environment of improper use of mineral fertilizer. Many tropical soils are acidic by nature, and mineral fertilizer speeds up the acidification process. Consequently, soil productivity deteriorates rather than improves in the long term, and the fertilizer cannot have its full effects. Similarly the awareness of organic farming practices increased day by day throughout the world. Now the organic farming practices and organic amendments play a prominent role to mitigate the reclamation of soil fertility.

Analysis of sugar mill effluent and its influence on germination and growth of African marigold (Tagetes erecta L.)

Sugar industry is a very important agro-based industry in India and it discharges large amount of effluent into water bodies to create high pollution in water bodies which affects the plants and other living organisms. In the present investigation, the physico-chemical analyses of N. P. K. R. Ramaswamy co-operative sugar mill effluent was determined and impact of different concentrations (control, 10, 25, 50, 75 and 100%) of sugar mill effluent on seed germination behavior of African marigold (Tagetes erecta L.) was studied. The morphological parameters such as germination percentage, shoot length, root length, fresh weight and dry weight of seedlings, seed vigour index, tolerance index and percentage of phytotoxicity were calculated. The results recorded for the analyses of sugar mill effluent indicated their some parameters such as PH, EC, acidity, TDS, TS, BOD, COD, sulphate, magnesium, nitrogen, zinc, iron, copper, lead, manganese and oil and grease exceeded the permissible limit compared to Tamil Nadu Pollution Control Board (TNPCB) and then germination and growth parameters increased in lower (10%) concentration of sugar mill effluent and this morphological parameters gradually decreased with increasing effluent concentration. The lower (10%) concentration of sugar mill effluent may be used for irrigation purposes.

INFLUENCE OF CHROMIUM TREATMENT ON GROWTH AND NUTRIENT ACCUMULATION OF PADDY (Oryza sativa .L) SEEDLINGS.

The aim of this research is to study accumulation of Chromium along with nutrients and its effect on the growth of Paddy plant (Oryza sativa.L). Thus, paddy seedlings grown in petriplates lined with filter paper undergoing, different treatments of Cr (0, 2.5, 5, 10, 25, 50, 75, 100 and 200 mg/L). After one week seedlings were removed and morphological parameters like root length, shoot length and dry weight of plants and accumulation of nutrients along with Cr content were determined. The results indicated that the concentrations more than 100 mg/L chromium cause the reduction of morphological parameters in the treatment plants rather than control plant and Cr addition in the cultures caused enhancement of chromium content paddy seedlings. Similarly nutrient accumulation also affected by increasing concentrations of chromium.