Ikhtiar Khan

Impact of sewage contaminated water on soil, vegetables, and underground water of peri-urban Peshawar, Pakistan

The use of sewage-contaminated municipal water for irrigation of crops is an old practice in many big cities of Pakistan. Since the wastewater is rich in nutrients, it increases crops yield substantially but at the cost of food quality. The objective of this study was to investigate sewage water irrigation as a source of accumulation of heavy metals in soil and its subsequent transfer to crops and underground water. Sewage water, soil, groundwater, and crop samples were collected from selected areas around Peshawar city and analyzed for heavy metals concentration by atomic absorption spectroscopic method. Analysis of data revealed a considerable impact of the irrigation practices in the peri-urban Peshawar. Statistical analysis of the data showed a positive correlation between heavy metals concentration and soil carbon contents on the one hand and cation exchange capacity on the other. A strongly negative correlation was observed between metal contents and soil pH. The vertical movement of heavy metals from contaminated soil has polluted crops and underground water. The results indicated higher concentration of toxic metals in soil accumulated due to long-term sewage-contaminated water irrigation and their subsequent transfer to our food chain. The practice, if continued un-noticed may pose a threat of phytotoxicity to the local population.

Yield, chemical composition and nutritional quality responses of carrot, radish and turnip to elevated atmospheric carbon dioxide.

BACKGROUND Future concentration of carbon dioxide in the atmosphere is very important due to its apparent economic and environmental impact in terms of climate change. However, a compressive assessment of its effect on the nutritional and chemical characteristics of food crops has yet to be established. In the present study the impact of elevated atmospheric CO2 on the yield, chemical composition and nutritional quality of three root vegetables, carrot (Daucus carota L. cv. T-1-111), radish (Raphanus sativus L. cv. Mino) and turnip (Brassica rapa L. cv. Grabe) has been investigated. RESULTS The yield of carrot, radish and turnip increased by 69, 139 and 72%, respectively, when grown under elevated CO2 conditions. Among the proximate composition, protein, vitamin C and fat contents decreased significantly for all the vegetables while sugar and fibre contents were increased. Response of the vegetables to elevated CO2 , in terms of elemental composition, was different with a significant decrease in many important minerals. Elevated CO2 decreased the amount of majority of the fatty acids and amino acids in these vegetables. CONCLUSIONS It was observed that elevated CO2 increased the yield of root vegetables but many important nutritional parameters including protein, vitamin C, minerals, essential fatty acids and amino acids were decreased.

Carbon and nitrogen stoichiometry in Brassica napus L. seedlings after supplementation with Ca 2+ and K + under irrigated and drought stress conditions

Exposure of plants to long periods of water scarcity, mainly in arid and semi-arid regions, is one of the major reasons for over 50% reduction in average yields. Proper management of Brassica napus to enhance its ability to survive under drought and high temperature stress at early growth stages, besides development of tolerant genotypes, could improve its production in the rainfed areas. In the present study, we report the interactive effects of Ca 2+ , K + and N supplementation and water availability on the fresh biomass, N and C content, as well as C/N ratio of crop plants. Exposure to water stress significantly reduced the fresh biomass, Nitrogen (N), Carbon (C) content and the C/N ratio. Ca 2+ and K + supplementation before drought positively affected fresh biomass by stimulating N uptake and C assimilation. However, the C/N ratio was reduced after supplementation with Ca 2+ and K + . The N supplementation before drought imposition, though enhanced the N uptake, but the excessive damage to cell membranes and electrons leakage from Electron Transport Chain (ETC) during photosynthesis resulted in a decrease in C assimilation. Consequently, there was a decrease in the C/N ratio in seedlings exposed to drought after supplementation with N. Key words : Drought, nutrients supplementation, carbon, nitrogen, C/N ratio.

Bioisosteric synthesis of nitrogen containing derivatives of salicyl alcohol, their in vivo pharmacological studies with molecular modeling

Starting with salicylaldehyde, compounds (I) [1-(2-hydroxybenzyl)piperidinium chloride] and (II) [4-carbamoyl-1-(2-hydroxybenzyl)piperidinium chloride] were prepared via multi step synthesis. The synthesized compounds were evaluated in vivo for their anti-inflammatory, analgesic, and anti-pyretic activities. Both compounds showed significant pharmacological profile when compared with reference standard, aspirin. In an attempt to understand the ligand–protein interaction in terms of the binding affinity, the synthetic molecule II was subjected to docking analysis using AutoDock which showed better binding modes with the active sites of COX’s enzymes.

2-(6-Meth­oxy­naphthalen-2-yl)-1-(morpholin-4-yl)propan-1-one

In the title compound, C18H21NO3, the naphthalene group and the basal plane of the morpholine ring (r.m.s. deviations = 0.0177 and 0.0069 Å, respectively) are oriented at a dihedral angle of 44.0 (2)°. In the crystal, molecules are linked by C—H⋯π interactions.

2-(4-Isobutyl­phen­yl)-1-(morpholin-4-yl)propan-1-one

In the title compound, C17H25NO2, the morpholine ring adopts a chair conformation. The benzene ring makes a dihedral angle of 39.81 (13)° with the basal plane of the morpholine group.

Enhanced antioxidant defense after exogenous application of Ca 2+ and K + in brassica napus seedlings under water deficit stress

Supply of adequate moisture is one of the most important factors limiting agricultural extension and productivity. Ca 2+ and K + are both essential plant nutrients required in a number of developmental and metabolic processes. Both of these nutrients play an important role in ameliorating drought stress in crop plants. This experiment was designed to study whether exogenous application of Ca 2+ and K + before the drought could enhance the potential of plants to survive under limiting water conditions. Brassica napus L. cv Bulbul-98 seedlings were exposed to drought stress for 10 days after exogenous application of different concentrations of Ca 2+ , K + and N through irrigation water. Exogenous Ca 2+ and K + application was associated with increased relative water content, membrane stability and chlorophyll content in seedlings exposed to water deficit. Though the quantity of Pro and activities of APX (EC: 1.11.1.11) and CAT (EC: 1.11.1.6) were increased after K + application, they were strongly induced in seedlings supplemented with Ca 2+ in a dose dependent manner. Increasing quantity of N application, however, had a negative effect on these parameters. Key words : Drought, Ca 2+ , K + , AOS enzymes, proline, chlorophyll.

Absolute configuration of (2S)-4-(4-hy­droxy­phen­yl)butan-2-ol

The title compound, C10H14O2, was isolated from the chloroform extract of Taxus wallichiana Zucc. In the crystal, molecules are linked by intermolecular O—H⋯O hydrogen bonds, forming sheets parallel to (100). There are weak intermolecular C—H⋯π interactions between the sheets.

2-{2-[(2,6-Dichloro-phen-yl)amino]-phen-yl}ethanol.

In the title compound, C14H13Cl2NO, the 2,6-dichloroanilino unit is roughly planar (r.m.s. deviation = 0.0298 Å) and makes a dihedral angle of 67.71 (4)° with the benzene ring containing the ethanol group. The C–C–O fragment is oriented at a dihedral angle of 64.94 (9)° with respect to its parent benzene ring. The molecular conformation is stabilised by a bifurcated N—H⋯(O,Cl) hydrogen bond. C—H⋯π, O—H⋯π and π–π interactions [centroid–centroid distance = 3.5706 (11) Å] stabilize the crystal structure.

[2-(2,3-Dimethyl-anilino)phen-yl]methanol.

In the title compound, C15H17NO, the 2,3-dimethylphenyl group is disordered over two sites with an occupancy ratio of 0.869 (3):0.131 (3). The major and minor components of the 2,3-dimethylanilino group are planar, with r.m.s. deviations of 0.0214 and 0.0303 Å, respectively, and are oriented at a dihedral angle of 2.6 (6)°. The phenylmethanol–benzene ring is oriented at dihedral angles of 83.16 (6) and 81.0 (3)° with respect to the major and minor components of the 2,3-dimethylanilino group, respectively. An S(6) ring motif is present due to intramolecular N—H⋯O hydrogen bonding. In the crystal, molecules are connected into supramolecular chains via O—H⋯O hydrogen bonding along the b axis. C—H⋯π interactions help to stabilize the crystal structure.