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Salinity intrusion is a global concern in relation to sustainable agricultural practices. About three-fourths of the coastal area in Bangladesh is affected by different levels of salinity. This study was conducted to observe the effects of NaCl-salinity on tomato (Lycopersicon esculentum Mill.) plants in a pot experiment. Morphological properties and yield of five varieties of Bangladesh Agricultural Research Institute tomato (BARI-T 1, BARI-T 2, BARI-T 3, BARI-T 4, and BARI-T 5) plants were exposed to NaCl-salinity (2, 4, 6 and 8 dS/m) through irrigation. Morphological properties such as number of leaves, leaf length, leaf width, number of days of flowering, number of flowers and number of branches were observed. Results showed that morphological properties of all studied tomato plants were affected by increasing NaCl-salinity, except number of days of flowering, and yield was reduced compared to the control group (tap water; 0.043 dS/m). The post-harvest pot soil was also affected by NaCl-salinity irrigation. This study can be useful in selecting salt-tolerant varieties in saline-affected areas.

A solution culture experiment was conducted to screen out 16 Bangladeshi tomato germplasm for salinity tolerance with respect to severity of leaf symptoms, shoot and root dry matter production, fruit yield, shoot Na+, K+, Ca2+ accumulation and their respective ratios by exposing up to 120 mM NaCl. The salinity tolerance scale ranged from 1.0 (most tolerant) to 3.5 (most sensitive). Based on the severity of leaf symptoms, “BT14 (BARI Tomato 14)” and “BHT5 (BARI Hybrid Tomato 5)” were found to be most tolerant germplasm to salinity with score 1.0. Reduction of dry weight was found to be 19% (shoot) and 15% (root) in BT14 and BHT5, 30 - 76% (shoot) and 27 - 83% (root) in other germplasm. Higher correlation was found between salinity tolerance scale classes and the reduction of shoot/root dry weight, Na+ concentration, K+/Na+, and Ca2+/Na+ ratios in BT14 and BHT5 germplasm. The fruit yield of BT14 and BHT5 germplasm was less and decreases with high salinity. Thus, “BT14” and “BHT5” can be regarded as a breeding material for development of new tomato varieties resistant to salinity.

Solid waste production is rapidly increasing in Bangladesh and landfill leachate is the consequence of the decomposition of this waste. These leachates contain heavy metals and significant amount of dissolved organic matter (DOM). DOM is known to have considerable role in heavy metals speciation. Hence, it is important to characterize DOM/leachate and evaluate toxic metals binding affinity of DOM. The objectives of this study were to characterize the DOM in landfill leachate through physico-chemical and optical analyses and to investigate the toxic metals (Ni2+, Pb2+ and Hg2+) binding affinity of three different ages (fresh sample L-1, young sample L-2 and mature sample L-3) DOM samples. Results suggested that leachate is a potential pollutant which contained very high organic pollutant load. Conditional stability constant (LogK) and percentages of fluorophores that correspond to metal binding (%f) values indicated that young DOM sample (L-2) had the highest binding affinity to all the three metals ions. In general, DOM samples showed the following order affinity to the metal ions; Ni2+ binding affinity: L-2 > L-3 > L-1, Pb2+ binding affinity: L-2 > L-3 > L-1 and Hg2+ binding affinity: L-2 > L-1 > L-3.

A total of 21 water samples were collected from surface water (ponds and river) and groundwater samples from shallow tube well (STW) and deep tube well (DTW) from Gopalganj Sadar Upazila to evaluate the salinity hazard and suitability for irrigation purposes. Both surface and groundwater of the study area maintained the trend of Cl− > SO4 2− > PO4 3−. The cation trend in both surface and groundwater of the study area was Na+ > K+ > Ca2+ > Mg2+ > Fe. Correlation matrices and principal component analysis (PCA) confirmed the stress of salinity from elevated electrical conductivity and total dissolved solids (TDS) with Na+, K+, Cl− and total hardness (TH) in relation to Ca2+, Mg2+, PO4 3− and SO4 2−. Salinity hazard classification and Wilcox diagram for irrigation water classification demonstrate that shallow tube wells containing low alkali and low sodium hazard are an excellent source of irrigation waters and fall under good to fair class of water (55 % samples). Higher TH, sodium adsorption ratio (SAR), soluble sodium percentage (SSP) and other important analysis indicated that most of the surface water and DTW were not suitable for irrigation. Therefore, the best irrigation water quality was from STW. Nevertheless, to sustainably and efficiently utilize the existing water resources, cyclic conjunctive uses of river water, STW and DTW as well as excavation of pond to store rainwater were suggested.

Comparative study was conducted to correlate arsenic (As), iron (Fe), copper (Cu), manganese (Mn), calcium (Ca2+), magnesium (Mg2+), potassium (K+), nitrate (NO3 −), phosphate (PO4 3−), and ammonia (NH3) by determining their concentration at different depths of the tube-wells in the selected study area at Singair, Manikganj Bangladesh. Total 99 tube-well water samples were collected from the study area. In most of the sampling points, the present concentrations of As were less than the previous concentrations. The correlation between As and Fe was positively significant. It can be suggested possible adsorption/co-precipitation of As with Fe in shallow aquifer. However, the relationship between As and Mn was not significantly observed. On the other hand, relationship between Cu and As showed a positive significant correlation. The correlation between As and PO4 3− was also significant, although the correlation between As and NO3 − was not significant. PO4 3− may come from phosphate fertilizers application and can be a contributor of As in the shallow aquifer. The PCA biplot also indicated the significant relationship between As, Cu, Fe and PO4 3−. Excessive withdrawal of tube-well water along with aquifer dynamics and ionic interference might be responsible for the mobilization of As in the study area.

A study based on the physicochemical parameters and dissolved metals levels from three main rivers around Dhaka City, Bangladesh, was conducted in order to determine the present pollution status and their alteration trends with the seasonal change of discharge amount. The water samples were collected from the rivers Buriganga, Turag, and Shitalakkhya during both dry and monsoon seasons. Physicochemical analyses revealed that most of the water quality parameters exceeded the recommended levels set by the Department of Environment (DoE), Bangladesh, during both the dry and monsoon seasons. A very strong positive correlation was found between biochemical oxygen demand (BOD) and chemical oxygen demand (COD) in all sampling points. Both BOD and COD values had a strong negative correlation with dissolved oxygen (DO) in the Shitalakkhya River. Most of the dissolved metals concentrations in the water samples were similar. However, the concentrations of different physicochemical properties varied with the seasons. The dry season had significantly higher contamination loads, which were decreased during the monsoon season. Anthropogenic activities, as well as the variation in river water flow during different seasons were the main reasons for this high degree of water pollution.

DOI: http://dx.doi.org/10.3329/jueb.v1i0.14547 Jahangirnagar University Environmental Bulletin, Vol.1, 41-53, 2012

A field study was conducted to screen out a number of Bangladeshi Tomato (Lycopersicon esculentum L.) varieties for salinity tolerance. Three levels of salinity were 2.0-4.0 dS m-1, 4.1-8.0 dS m-1 and 8.1-12.0 dS m-1. Significant varietal and or salinity treatment effects were registered on plant height, leaf area, plant growth, yield, dry matter plant-1, Na+ and Claccumulation in tomato tissues. Variety BARI Tomato 14, BARI Hybrid Tomato 5 and BARI Tomato 2 consistently showed superior biological activity at moderate salinity (4.1-8.0 dS m-1), based on dry matter biomass production thus displaying relatively greater adaptation to salinity. Under saline condition, all plant parameters of tomato varieties were reduced compared to the control except number of fruits of BARI Tomato 14, BARI Hybrid Tomato 5 and BARI Tomato 2. Thus, BARI Tomato 14, BARI Hybrid Tomato 5 and BARI Tomato 2 can be regarded as a breeding material for development of new tomato varieties for tolerance to salinity in saline areas of Bangladesh. DOI: http://dx.doi.org/10.3329/ijarit.v2i1.13989 Int. J. Agril. Res. Innov. & Tech. 2 (1): 13-18, June, 2012

Several UV-curable formulations containing epoxydiacrylate (EB-600) oligomer with a tri-functional monomer, trimethylol propane triacrylate (TMPTA), and photoinitiator Irgcure-369 were developed to improve the surface of Partex. Filler or extender CaCO3 was incorporated into the solution. Thin polymer films were prepared on glass plate with these formulated solutions and finally applied on polished Partex surface, and both were cured under UV-radiation. The properties of UV-cured thin films were studied as a function of CaCO3 concentration. Pendulum hardness and gel content were found to decrease on glass plate with the increase of CaCO3 concentration. Pendulum hardness, scratch hardness, and abrasion resistance of the cured Partex were found to be higher with the increase of CaCO3 content up to 4%. Thus, the formulation containing 4% CaCO3 showed the best performance over all formulations containing CaCO3. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1858–1867, 2001

A urethane prepolymer with an aliphatic chain, has been used to prepare a number of formulations, in the presence of plasticizers and monomers of different characteristics. Hessian cloth (jute product) is coated with these formulations and cured under u.v. radiation. Tensile properties (strength and elongation) of the jute plastic composite, thus formed with these formulations were found to increase. The treated jute products (composites) were buried in soil, semi-mud, mud and water in order to study the degradable character of the composite. It was found degradable in mud while the composite was not decomposable in water and soil. The composite was also treated under the simulated weathering conditions by alternating sunshine, and condensation and it was found that the composite was substantially decomposed under this condition.

A number of formulations was developed with oligomer mixed with functional monomers in the presence of fillers and plasticizer. Then polymers were prepared under UV radiation with these formulated solutions. The films were characterized to determine film hardness, gel and tensile properties. Jute yarns were treated with these formulated solutions and cured under the same UV source. More than 80% grafting occurred with the yarn; mechanical strength of the treated yarn increased to 55% and its elongation enhanced by 3 fold. Simulating weathering caused tensile strength loss between 40 and 70% and elongation by 40–70% depending on the formulations. The jute yarn plastic composite was found to be quite durable in normal conditions but it can be made degradable in certain environmental conditions to different degrees depending on the nature of the formulations.

Ten different formulations are prepared with a urethane acrylate oligomer in combination with two monofunctional monomers (EHA with low T g and NVP with a carboamide group) and a difunctional acrylate monomer (TPGDA) in the presence of a plasticizer. Polymer films are prepared with these formulated solutions under UV radiation. Their properties (gel, hardness, tensile characters, etc.) are determined. These solutions are coated on leather substrates and cured under UV radiation. The improvement of quality of leather is manifested through the enhancement of tensile strength and elongation of the coated leather. The coating also imparts high gloss on the leather surface as well as high wear resistance. It also protects the leather from the damage of weathering effect. The best formulation is determined to be the one containing NVP with a carboamide group and a plasticizer.

Twelve different formulations were developed with urethane acrylate oligomer in combination with a number of functional monomers in the presence of different additives, fillers, and plasticizers. Hessian cloth (jute product) was coated with these formulated solutions and cured under UV radiation. Enhancement of tensile strength and elongation was determined. Loss of these properties due to simulating weathering was also measured. The treated Hessian cloths were buried in soil, water, and mud for a long period and it was found that the samples put in mud were completely degradable while those treated in water and soil retained their tensile properties. © 1995 John Wiley & Sons, Inc.

During an analysis of DNA enzymes by gel electrophoresis, we found that some DNA enzymes can adopt more than one conformation. The DNA enzyme Dz31 that formed more than one conformer contained a stretch of G residues. Further investigations, involving kinetic analysis and measurements of circular dichroism, indicated that this DNA enzyme and its derivatives formed G-quadruplexes. Moreover, we found that some derivative oligomers were capable of forming dimeric G-quadruplexes. We also compared the catalytic activities of Dz31 and its mutant derivatives. The present findings suggest that DNA enzymes with five or more continuous G residues are less favorable than those without G5 in the association step in the enzymatic reaction and, thus, the choice of targets that contain a continuous stretch of C residues downstream of the cleavage site should be avoided. In addition, we found that negative charge–charge repulsion disrupted the dimerization of G-quadruplexes when a phosphate group was added directly to the 5′-terminal G of oligomers with continuous guanosine residues. In the case of 5′-phosphorylated G5CTA, direct attachment of a phosphate group to the continuous G5 sequence inhibited dimerization of G-quadruplexes, at least during electrophoresis on a denaturing gel.

Zinc complexes of histidine-containing peptide derived from N,N′-dihistidylethylenediamine L1 and im-bzl-N,N″-dihistidyldiethylenetriamine L2 were designed and examined as catalysts for hydrolyses ...

The deprotonation of the zinc-bound water and the zinc-bound bicarbonate which arose from hydration of CO2 have been simulated in vitro according to the proposed mechanism for carbonic anhydrase, with the model complex of its own active site, [LZn(OH2)]2+, where L = tris(2-benzimidazolylmethyl)amine.