Effects of nickel toxicity on morphological and physiological aspects of osmoregulation in <Emphasis Type="Italic">Typha domingensis</Emphasis> (<Emphasis Type="Italic">Typhaceae</Emphasis>) populations

The present work examined morphological and physiological aspects of osmoregulation in some differently adapted populations of Typha domingensis. Six populations of T. domingensis were grown in waterlogged conditions under four levels of nickel (0, 50, 100 and 1500 mg/kg of Ni). The Ni tolerance was explored on the basis of different characteristics of shoots. Along with the increasing level of Ni stress, all populations showed an increment of proline and glycinebetaine content, low photosynthetic and transpiration rates and decreased chlorophyll content. Analyzed morphological parameters revealed possible adaptations to deal with Ni stress. The less tolerant Sahianwala population produced more aerenchyma, less accumulation of osmolytes and reduced shoot fresh weight under Ni stress than the tolerant ones. Our results suggested that T. domingensis has the capacity to survive under Ni stress and could be used for the absorption of toxic metal ions from industrially polluted water.     

Characterization of Asymmetric Tapered Dipole Nanoantenna for Energy Harvesting Applications

In this paper, systematic study for asymmetric tapered dipole nanoantenna is implemented using finite element frequency domain (FEFD) solver where harvesting efficiency, field confinement, surface current, and input impedance are calculated at wavelength of 500 nm. The proposed nanoantennas achieve a harvesting efficiency of 61.3% and a field enhancement factor of 37.7 over the conventional dipole nanoantenna. This enhancement is attributed to the irregularity of the surface current distribution on the asymmetric designs. Particle swarm optimization technique is used to find the optimum design geometrical parameters through an external link between the optimization algorithm and the FEFD solver. Moreover, the proposed designs offer a resonance impedance of 500 Ω to match that of fabricated rectifiers. Further study of the structure fabrication tolerance is included which shows the robustness of the proposed nanoantennas.     

Role of Zinc–Lysine on Growth and Chromium Uptake in Rice Plants under Cr Stress

Journal of Plant Growth Regulation - Chromium (Cr) is a very toxic heavy metal present in agricultural soils. Soils contaminated with Cr are the major source of Cr entrance into the food chain. The...     

A study on distribution of natural radionuclide polonium-210 in a pond ecosystem

This paper presents the results of an investigation on the distribution of²¹⁰Po in Mutharasanallur pond ecosystem. It has been demonstrated that²¹⁰Po is non-uniformly distributed within the ecosystem. The results of the study show a dissolved²¹⁰Po concentration in pond water of 1 4mBq 1₋₁. The sediment samplso recorded a²¹⁰Po activity of 59 9 Bq kg₋₁. The aquatic organisms showed differential accumulation of the radionuclide with enhanced bioaccumulation in soft tissues and muscle. The²¹⁰Po activity in the biota fell within the range of 1·2–53 3 Bq kg₋₁ (wet wt). The bivalve mussel,Lamellidens marginalis was identified to accumulate higher concentration of²¹⁰Poin soft tissues, suggesting that these organisms could serve as a bio-monitor of²¹⁰Po radionuclide in a freshwater system. The concentration factors of²¹⁰Po for the biotic components ranged from ∼10²–∼10⁴. Analyses of the results indicate that prawn and fish represent an important source of supply of²¹⁰Po to humans via dietary intake. Results of²¹⁰Po activity in the abiotic and biotic components of the pond ecosystem were higher when compared with those of Cauvery river system, the primary water source of the pond.     

Production of alkaline protease by a new Bacillus subtilis isolate for use as a bating enzyme in leather treatment

Bacillus subtilis, isolated from tannery waste, produced an alkaline protease at optimal activity when grown in a casein/gelatine medium in a stirred tank fermenter at 37°C with the dissolved oxygen tension at 40% air saturation. Optimum protease activity (223 U ml^-1) was at pH 8.5 and was stable for 1 h up to 45°C but at 60°C lost 80% activity. Use of the crude protease as a bating agent for producing high quality leather is indicated. Tensile strength, bursting strength, tear strength and elongation at break of prepared leather were increased with increasing amounts of protease used for bating.A. Hameed and M.A. Natt are with the Department of Biological Sciences, Quaid-i-Azam University, Islamabad. Pakistan. C.S. Evans is with the School of Biological and Health Sciences, University of Westminster, London. UK.     

Weeds ability to phytoremediate cadmium-contaminated soil

An alternative method to other technologies to clean up the soil, air and water pollution by heavy metals is phytoremediation. Therefore, a pot culture experiment was conducted at the College of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran, in 2014 to determine the potential absorption of cadmium by Portulaca oleracea (Common purslane), Solanum nigrum (Black nightshade), Abutilon theophrasti (Velvetleaf) and Taraxacum officinale (Dandelion). The type of experiment was completely randomized design with factorial arrangement and four replications. The soil in pot was treated with different rates of CdCl₂.H₂O (0 (control), 10, 20, 40, 60, and 80 mg Cd/kg soil) and the plants were sown. With increasing concentration levels, fresh weight and dry weight of shoots and roots of all plant species were reduced. The reduction severity was ranked according the following order, P. oleracea > A. theophrasti > S. nigrum > T. officinale. Bioconcentration factor (BCF), Translocation factor (TF) and Translocation efficiency (TE%) was ranked according the following order, T. officinale > S. nigrum > A. theophrasti > P. oleracea. The results of this study revealed that T. officinale and S. nigrum are effective species to phytoremediate Cd-contaminated soil.     

Variation in temperature and light but not salinity invokes antioxidant enzyme activities in germinating seeds of Salsola drummondii

Seeds with efficient antioxidant defence system show higher germination under stress conditions; however, such information is limited for the halophyte seeds. We therefore studied lipid peroxidation and antioxidant responses of a leaf-succulent halophyte Salsola drummondii during seed germination under different salinity levels (0, 200 and 800 mM NaCl), temperature (10/20, 20/30 and 25/35°C) and light regimes. Seeds absorbed water and germinated in less than 1 h in non-saline control while increases in salinity decreased the rate of water uptake as well as seed germination. Non-optimal temperatures (10/20 and 25/35°C) and complete dark condition reduced seed germination in comparison to those seeds germinated under optimal temperature (20/30°C) and 12-h photoperiod, respectively. Generally, higher lipid peroxidation and antioxidant enzyme activities were observed in seeds at non-optimal temperature and in those seeds germinated in dark. Decrease in reduced ascorbic acid content was found in highest salinity and temperature treatments, while reduced glutathione content did not change significantly with changes in salinity, temperature and light regimes. These results indicate variation in temperature and light but not salinity enhances antioxidant enzyme activities in germinating seeds of Salsola drummondii.