Composts with five different ratios of agricultural wastes, viz. rice straw (RS), wheat straw (WS), potato plant (PP), and mustard stover (MS) were prepared with or without fish pond bottom sediment to investigate the compost maturity and their suitability for field application. The composting process was monitored through the changes in physico‐chemical parameters and germination index (GI) at every 7 days interval of the composting process. All the composts were dark brown and smelled like forest soil within 56 days of composting, which reflected its matured status. On the basis of the physico‐chemical parameters (bulk density: 0.84 g/cm3; pH 7.05; electrical conductivity: 3.52 mS/cm; cation exchange capacity:82.4 cmol/kg; total carbon:321.4 g/kg; total nitrogen: 16.9 g/kg; As: 6.8 mg/kg; Cd: 2.96 mg/kg; Cr: 29.6 mg/kg, Cu: 243.6 mg/kg; Hg: 0.019 mg/kg; Ni: 24.3 mg/kg; Pb: 62.1 mg/kg and Zn: 812 mg/kg) and GI (89–96%), it could be concluded that RS/WS/PP/MS, 1:1:2:1 v/v/v/v with fish pond sediment produced better compost in accordance with the Indian compost standard. Application of a combined randomized block design analysis revealed that there is a significant difference in the responses of the five composts, in relation to the time of composting. Hierarchical clustering algorithm was applied with a view to form homogeneous groups of five different composts on the basis of different physico‐chemical parameters. Therefore, the ratio of waste incorporation is an important decision for composting and addition of pond sediment can improve the quality of compost.

The present article discusses an overview on the contamination of non-segregated open municipal solid waste (MSW) in and around a dumping site at Garchuk in Guwahati city, Assam, India. Analysis showed depth-wise variations in the concentrations of selected heavy metals in MSW and their subsequent accumulations with increasing depths. Zinc was the most abundant heavy metal in MSW. Six-step selective sequential extractions revealed that most of the heavy metals in MSW were in the residual phase except zinc. Analysis of the leachate from MSW showed high concentrations of fluoride, chloride, ammonium-nitrogen and the ratio of biological oxygen demand/chemical oxygen demand. Concentrations of all the heavy metals in the leachates were higher than the Indian national effluent standards. High amounts of biological oxygen demand, heavy metals, total and fecal coliforms in water samples from the adjoining water body (Deepor Beel, a Ramsar site) of the MSW dumping site indicated its unsuitability for domestic use. Principle component analysis showed that influence of MSW leachate was the major source of water contamination in Deepor Beel. Though accumulation of heavy metals in different vegetables growing in MSW dumping site did not exceed the recommended maximum intake, it was a significant additional source of heavy metals in cooked human diet.

Axillary shoot bud multiplication has been achieved in Eucalyptus tereticornis Smith. using explants from different regions of 8-10 years old elite trees, growing in the field. Results showed that addition of NAA at 0.1 mg 1-1 and BAP at 1.0 mg 1-~ to modified MS medium induced maximum number of shoot buds. For inducing axial growth in regenerated bud primordia, the hormone concentration of the medium was lowered. The addition of charcoal and gibberellic acid to the medium were beneficial. Rooting was best in Knop's medium containing 1.0 mg 1-~ IBA. The key factor in root induction was primarily a dark incubation for a short period. The percentage of both rooting of shoots and survival of the rooted shoots was 60-80.Continuous trials using explants from the elite trees throughout the year showed that the period between July-September was the best season for the explant source for rapid and increased multiplication of axillary buds. Phenolic exudation was also minimum at this period. The experiments were repeated using 50 populations from different plantations. It was observed that during culture, genotypically different populations responded differently in spite of optimal growth conditions.

Living, unstained, single tobacco (Nicoliana tabacum × N. glutinosa) cells (clone H‐196) were grown in microcultures in liquid medium containing sucrose, mineral salts, coconut milk and 2,4‐dichlorophenoxyaeetic acid. Time‐lapse motion pictures were taken through interference and phase microscopes. The movement of cytoplasm and cell organelles gradually slowed and ultimately completely ceased as the cell was cooled by dry ice. The cessation of the movement of cell organelles took place between 5 and –7C. The typical cytoplasmic morphology was lost as the movement slowed. The cytoplasmic strands thinned out and numerous small vacuoles formed. During rewarming of the cell to room temperature, the vacuoles were replaced by numerous small globular masses of cytoplasm which reorganized into cytoplasmic strands. The normal movement of cytoplasmic strands and cell organelles was resumed. A number of small nucleolar vacuoles at room temperature gradually expanded and coaleseed to form a large central vacuole which underwent further expansion and then contracted rapidly. Four different concentric zones were visible across the nucleolar region. A white, highly reflecting, glossy substance appeared on the surface of the expanding vacuole. The position of the nucleus during contraction and expansion was never stationary. Some nucleolar vacuoles remained open for an indefinite period of time when the cell was cooled to 5C. No change was noticed during cooling, but during rewarming to room temperature, the nucleolar vacuole was partially closed. The pumping action of the nucleolar vacuole suggested important exchanges of metabolites between the nucleolus and the cytoplasm. A single cell of tobacco did not divide at –10C, but mitosis proceeded upon cooling the cell to – 12–15C for a brief period. Different phases of mitosis, specifically formation of the cell plate, cell wall, and separation of nuclei, were delayed by low temperature treatment.

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