Animesh Sarkar

SCREENING FOR PHOSPHATE SOLUBILIZING BACTERIA INHABITING THE RHIZOPLANE OF RICE GROWN IN ACIDIC SOIL IN BANGLADESH

The objectives of the research were to isolate phosphate solubilizing bacteria (PSB) from the rhizoplane of rice (Oryza sativa L.) cv. BRRIdhan 29 cultivated in acidic soils of Tangail in Bangladesh and evaluate their performances in phosphate solubilization in both in vitro and in vivo conditions. A total of 10 bacterial strains were isolated and purified by repeated streak culture on nutrient agar medium. Upon screening, five isolates (OS01, OS03, OS07, OS08 and OS10) showed varying levels of phosphate solubilizing activity in agar plate and broth assays. Among them, the strain OS07 (B1) and two previously isolated PSB strains B2 and B3 were selected for evaluation for their performances in rice alone or in combination of TSP (triple super phosphate: P1) and rock phosphate (P2). Plant height and the number of tillers per plant were significantly increased by all PSB isolates when used in combination with TSP but PSB alone did not influence much on plant height and the number of tillers except B1. The levels of mineral nutrients content in rice plant tissues were generally increased by the application of the PSB in combination with TSP, while the performances of B1 isolate was superior in all aspects to B2 and B3 isolates.

Arbuscular Mycorrhizal Association for Growth and Nutrients Assimilation of Pharagmites japonica and Polygonum cuspidatum Plants Growing on River Bank Soil

ABSTRACT Effects of arbuscular mycorrhizal fungi (AMF) on the growth, nutrient absorption, and inoculation effectiveness of AMF on pioneer plants Pharagmites japonica (C4) and Polygonum cuspidatum (C3) were evaluated by performing a pot experiment in a greenhouse at Saitama University, Japan. AMF spores were collected from the commercial product, Serakinkon. The average colonization levels of P. japonica and P. cuspidatum were 24–33% and 0.2–0.5% respectively and no colonization was found in sterilized soil treatment. AMF colonization increased the plant dry mass, phosphorus (P), and nitrogen (N) concentrations of P. japonica’s roots, stems, and leaves when AMF applied with natural and sterilized soil compared with only sterilized and natural soil. This was a significant effect for N-loss minimization from soil. Maximum value showed when P. japonica was grown with natural soil in combination with AMF whereas P. cuspidatum showed very less or a negative response to AMF colonization in all cases.

Role of arbuscular mycorrhizal fungi on the performance of floodplain Phragmites japonica under nutrient stress condition

A pot experiment was conducted to evaluate the potential effects of arbuscular mycorrhizal fungi (AMF) on growth, nutrient uptake, and inoculation effectiveness on Phragmites japonica. Spores of AMF strains (Gigaspora margarita Becker & Hall) were collected from the commercial product ‘Serakinkon’. Four treatments, namely, natural soil (NS), natural soil inoculated by AM fungi, sterilised soil (SS) inoculated by AM fungi, and SS without AM fungi inoculation were selected to determine the effects of applied and indigenous AMF on P. japonica. The average colonisation level of P. japonica was 24–33%, whereas no colonisation was found in the SS. AMF colonisation increased the chlorophyll content (r = 0.84, p < .01), plant dry mass (r = 0.89, p < .01), and N, P, K, Mg, and Fe concentration of the plants roots, stems, and leaves when AMF was applied with natural and SS. In all cases, maximum values were found when the plants were applied with NS in combination with AMF, but Ca concentration decreased as the colonisation level increased. Mn concentration decreased in the roots, but increased in the leaves. Cu concentration was not significantly affected by treatments. N-loss minimisation from the soil was significant when the colonisation level was high.

Investigation of condensation reaction during phenol liquefaction of waste woody materials

The liquefaction of waste woody materials in the presence of phenol and acid catalyst is a promising method for converting waste woody materials into phenolic resin. The condensation reaction during the liquefaction process is a major problem for its practical application. The effects of various reaction conditions on the extent of the condensation reaction were investigated. The residue content, molecular weight distributions and phenol concentration were measured to investigate the condensation reaction. As a result, it was observed that the intense reaction conditions caused fast liquefaction and led to a remarkable condensation reaction. It was also found that the residue content began to increase at an earlier reaction time when a more remarkable condensation reaction occurred. These results indicated that the condensation reaction was one of the causes for too much degradation of liquefi ed wood molecules under intense liquefaction. The phenol concentrations in the liquefaction products were measured to investigate their effect on the condensation reaction. It was shown that the phenol concentration was 8% lower at the end of the reaction when the condensation reaction was high. It was indicated that the drop in phenol concentration suppressed the liquefaction and promoted the condensation reaction. The addition of methanol during the liquefaction process suppressed the condensation reaction. The residue content was 11% when 50% methanol was added, while it reached 66% when methanol was not added. This can be because methanol reduced the bound phenol, which could be a reaction site of condensation

Arbuscular mycorrhiza confers lead tolerance and uptake in Miscanthus sacchariflorus

ABSTRACT The effects of an arbuscular mycorrhizal fungi (AMF) association on the growth, survival capabilities, nutrients and lead (Pb) uptake of Miscanthus sacchariflorus under different Pb concentrations were studied in the form of pot cultures. The treatments comprised inoculation or non-inoculation of the AMF, Gigaspora margarita, and the addition of three Pb concentrations to the soil (0, 100 and 1000 mg kg−1). The addition of Pb significantly decreased mycorrhizal colonisation. The inoculation of AMF with Pb increased chlorophyll content, Fv/Fm, total dry mass, indole-3-acetic acid (IAA), total nitrogen, and total phosphorus, whereas H2O2 level, indole-3-acetic acid oxidase (IAAO) activity, and peroxidase (POD) activity were low compared to those in the non-inoculated treatments. Moreover, the application of AMF together with Pb doses induces concentrations of Pb in the plant, where the higher dose of Pb (1000 mg kg−1) induces a lower content of Pb in the aerial part of the plant but a higher content in the root. G. margarita enhanced the tolerance of M. sacchariflorus against Pb toxicity, and facilitated the accumulation of Pb in the plant roots, whereas translocation to the shoots was inhibited at the highest dose Pb (1000 mg kg−1). However, in contaminated soil, the Pb removal capability of M. sacchariflorus with AMF was remarkable.

Biocontrol Potentiality of Isolated Trichoderma spp. against Pestalozzia theae Saw. in Tea

Isolates of Pestalozzia theae Saw. and Trichoderma spp. were collected from Bangladesh Tea Research Institute (BTRI) farm area, Bangladesh. The cultural morphology and antagonistic potentiality of Trichoderma spp. against grey blight pathogen Pestalozzia theae was studied for tea cultivation. The antagonistic potentiality of Trichoderma spp., against Pestalozzia theae showed maximum (inhibition 84.45±0.77%) after 72 hrs of inoculation under in vitro condition followed by 76.02±3.50% after 24 hrs of inoculation. This study revealed that Trichoderma strain was highly effective to control Pestalozzia theae, the causal agent of grey blight disease of tea.

OIL AGGREGATED BEHAVIOR FOR COAL RECOVERY AND COMBUSTION CHARACTERISTICS OF THEIR AGGREGATES FROM DIFFERENT GRADE COALS

Large amounts of waste fi ne coals are very diffi cult to be treated due to the presence of ash and inorganic sulphur compounds. In order to use waste fi ne coal effi ciently, a retrieval technique is necessary for the recovery of combustible contents of coal from fi ne waste coals. Nowadays, a fl otation process has been used for the treatment, but it is impractical for developing countries due to its higher costs. Therefore, oil agglomeration process has been used to deal with these problems. In this study, the factors affecting the coal cleaning effi ciency of the oil agglomeration process were investigated with the element contents and chemical structure of three different grade coals. Chemical contents in three different grade coals were determined by proximate and ultimate analyses and the differences in chemical structure of carbonaceous contents of different grade coals were investigated by a Fourier transform-infrared spectrometry. In free coals or their mixed samples, the ratio of ash and carbonaceous contents were maintained to make it homogeneous. From the results of oil agglomeration experiments, it was concluded that the characteristics of agglomerate and the coal cleaning effi ciency of oil agglomeration were not only infl uenced by the type of oils but also by the oxygen contents and the aromatic and aliphatic chemical structures in different grade coals. The oxygenic functional groups of carbonaceous contents in coal samples prevented oil from attaching the carbonaceous surface and form the bulky aggregate. This depressed the combustible matter recovery, but this was resolved by changing the oil types. Oxygen contents in oils such as vegetable oil played a role in bridging material to the oxygenic functional groups of carbonaceous contents in coal samples. Meanwhile, it was observed that aromatic functional groups in carbonaceous contents interacted badly with the aliphatic functional groups in oil due to the resonance inspection of delocalized π electrons. Comparatively carbonaceous contents consisting of more aliphatic series or graphite-reinforced structures were tended to form aggregates easily. Even when different types of coals were used in the oil agglomeration, it was possible to achieve a better effi ciency by taking these factors into account. Moreover, by thermogravimetric-derivative thermogravimetric (TG-DTG) analyses, it was found that the combustion characteristics of carbonaceous contents were improved due to oil attachment.