ABSTRACT
Physic nut (Jatropha curcas) is an important commercial bio-diesel plant species and is being advocated for development of waste and dry land. The collar and root rot caused by Lasiodiplodia theobromae is an important soil borne disease which causes considerable yield loss in this crop. In this study, the effects of culture media, temperature, photoperiod, carbon and nitrogen sources and pH on mycelial growth and pycnidial production were evaluated. Among the growth media tested, potato dextrose agar supported the highest growth followed by potato sucrose agar and corn meal agar. Among several carbon sources tested, carboxy methyl cellulose and sucrose were found superior for growth and pycnidial production. The nitrogen sources viz., ammonium oxalate and ammonium dihydrogen phosphate were recorded maximum mycelial growth and pycnidial production. The fungus grows at pH 5.0-9.0 and optimum growth was observed at pH 7.0.
ABSTRACT
Carrot is a rich source of nutrients. The carrot contains carotene and lycopene, which gives bright color to the roots. The quality of the carrots was assessed based on the carotene, lycopene and other biochemical constituents like sugars, starch and protein. To study the effect of various isolates of the Erwinia carotovora var. carotovora on the above biochemical constituents, the pathogens were inoculated and the contents were analyzed separately at 1, 2, 3, 4, 5 days after inoculation. The contents of β-carotene increased significantly due to all the three isolates of the pathogen and the Coimbatore isolate recorded highest of 36.03 per cent. A same trend was also observed in the lycopene content with 93.55 per cent increase over control. The contents of total and reducing sugars were found to significantly increase due to inoculation with the pathogen. The starch content showed a decreasing trend in all the isolates tested. The maximum reduction of 62.98 per cent was observed in the roots inoculated with Coimbatore isolate.
ABSTRACT
Thirumullavaram temple pond associated with Sree Mahavishnu temple is located very close to the Arabian sea in Kollam municipality of Kerala. Physicochemical characteristics of water and sediment, productivity, plankton count, coliform count and correlation coefficients of various parameters were analysed for a period of one year from June 1999 to May 2000. It showed that the water characteristics such as conductivity, turbidity, colour, pH, total alkalinity, chloride, total hardness, silicate, phosphate, nitrate, iron, sodium and potassium; primary productivity, plankton count, and sediment characteristics such as pH, organic matter, potassium and nitrate registered higher values during non-rainy season. Coliform count recorded higher value during monsoon season. From the correlation study, it was inferred that several characteristics of water, sediment and primary productivity were interrelated. Comparison of water characteristics with BIS for drinking and swimming water showed that the pond water was mainly contaminated with coliform bacteria. However, the physico-chemical characteristics indicated that it could be used as a potential water source for drinking, swimming and for secondary production after proper treatment.