Antioxidative responses in relation to growth of mustard (Brassica juncea cv. Pusa Jaikisan) plants exposed to hexavalent chromium

Effect of hexavalent chromium (Cr6+) was seen on Brassica juncea cv. Pusa Jaikisan grown for 15 days in hydroponic culture supplemented with 0.2, 2 and 20 microM Cr. The inhibitory response of Cr6+ on growth of B. juncea was concentration and time dependent. The stimulation of plant growth, observed in response to exposure to 0.2 microM Cr6+, during initial 5 days was reversed on prolonged treatment and at higher Cr6+ concentrations (2 and 20 microM Cr6+). Despite reduction in growth, chlorophyll content increased substantially on 15 days exposure to 20 microM Cr6+. Significant increases in lipid peroxidation and tissue concentration of H2O2 occurred in plants exposed to 2 and 20 microM Cr6+. Effect of Cr6+ on antioxidative enzymes in roots and leaves was differential. SOD and CAT activities at lower levels of Cr6+ supply remained higher all through the treatment. While APX was very susceptible to excess Cr6+, GR and GST increased at elevated levels of Cr6+. The results suggested Cr6+ induced depression in plant growth of B. juncea to be a function of increased cellular accumulation of Cr despite increase in the activities of some of the antioxidative enzymes.     

Oxidisability of environmental sulphur under different catalytic conditions

The oxidation of elemental sulphur in the catalytic presence of selected metal ions [Cr(III), Ce(III), Cu(II), Hg(II), Ni(II), Co(II), Mo(VI), Cd(II), Zn(II), Ti(IV), and V(V)], and hydrocarbons (benzene, gasoline, and kerosene) was studied in an alkaline medium buffered by marble powder. The catalytic efficiencies of metal ions were: Cr(III) > Ce(III) > Cu(II) > Hg(II) > Ni(II). The oxidation process was inhibited in the presence of other ions, and the inhibitive effect was in the following order: Co(II) < Mo(VI) < Cd(II) < Zn(II) < Ti(IV) < V(V). In the case of hydrocarbons, the efficiencies were as follows: gasoline > benzene > kerosene. The oxidation of sulphur in sulphur-loaded soils obtained from near a textile mill and a distillery were also carried out in the c both cases was significantly enhanced.To whom all correspondence should be addressed.     

The recent occurrence of exotic freshwater fishes in the tributaries of river Ganga basin: abundance, distribution, risk, and conservation issues

We record here the recent occurrence, abundance and distribution of six exotic fish species, viz. Oreochromis mossambicus, Cyprinus carpio, Hypopthalmicthys molitrix, Ctenopharyngodon idellus, Clarias gariepinus, and Pterygoplichthys disjunctivus (a new exotic in India) distributed through the four important tributaries of river Ganga basin in India. From the total catch, the abundance index of all exotic species in different rivers ranged from 1.1 to 14.5?% with highest value in River Gomti. The relative abundance of the exotic species in all the four tributaries demonstrated that a single species C. carpio contributed a considerable abundance (43.3?C83?%) than that of the remaining exotic fishes. The Common Carp, C. carpio, was ubiquitous in all the four tributaries of Ganges basin studied and had the highest local distribution (52.63?%). Smaller size groups of endangered (Chagunius chagunio, Chitala chitala, and Tor tor) and migratory species (Bagarius bagarius, Ompok pabda, Wallago attu, and Sperata aor) in the four tributaries were recorded, and the increasing appearance of Common Carp and other exotic fishes is signaling biological invasion. Possible threats to the indigenous fish fauna, as a result of the invasion and proliferation of these exotics, are discussed.     

Characteristics of chlorofluorocarbons (CFCs) emitted from a municipal waste treatment facility

The emission concentrations of several chlorofluorocarbons (CFCs) were measured from a municipal waste treatment facility (located in Seoul, Republic of Korea) to investigate the emission characteristics of CFCs in the urban environment. To this end, a total of five CFCs (CFC-10, CFC-11, CFC-20, CFC-30, and CFC-113) were analyzed by the thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method. The results of this study indicate that the formation of CFC-11 (8.21 ± 1.68 ppb in spring) and CFC-20 (3.92 ± 3.93 ppb in spring) proceeded very actively within the facility. Moreover, CFC-113 was also found in relatively high concentrations (3.34 ± 1.31 ppb in spring) in the treatment facility. Unlike other CFCs, CFC-10 was observed mainly at ambient (and reference) locations and one point inside the treatment facility. In conclusion, emissions of some important CFCs are a prominent process, as they were measured either frequently or abundantly both in winter and spring. It is further indicated that certain CFCs (like CFC-11 and CFC-30) are subject to highly significant seasonal variations.     

Bracketing team boundary spanning: An examination of task‐based,team‐level,and contextual antecedents

There is growing recognition that teams do not function in a vacuum and that external boundary activities are important predictors of team performance, effectiveness, and knowledge sharing. In the past, researchers have focused on the effects of team composition or task characteristics as antecedents of critical boundary spanning activities. However, less effort has been directed at understanding how antecedents at multiple levels can simultaneously influence boundary spanning behavior in teams. This paper takes stock of over 20 years of research on the topic of team boundary spanning. Adopting a “bracketing” approach etc., we develop a multi‐level theoretical model to guide future research on the determinants of team boundary spanning. This model specifies task‐based, team‐level, and contextual antecedents of team boundary spanning and outlines the contingencies shaping the emergence of effective boundary‐management behavior in teams. Copyright © 2008 John Wiley & Sons, Ltd.     

Accumulation of heavy metals in dietary vegetables and cultivated soil horizon in organic farming system in relation to atmospheric deposition in a seasonally dry tropical region of India

Increasing consciousness about future sustainable agriculture and hazard free food production has lead organic farming to be a globally emerging alternative farm practice. We investigated the accumulation of air-borne heavy metals in edible parts of vegetables and in cultivated soil horizon in organic farming system in a low rain fall tropical region of India. The factorial design of whole experiment consisted of six vegetable crops (tomato, egg plant, spinach, amaranthus, carrot and radish) x two treatments (organic farming in open field and organic farming in glasshouse (OFG)) x seven independent harvest of each crop. The results indicated that except for Pb, atmospheric deposition of heavy metals increased consistently on time scale. Concentrations of heavy metals in cultivated soil horizon and in edible parts of open field grown vegetables increased over time and were significantly higher than those recorded in OFG plots. Increased contents of heavy metals in open field altered soil porosity, bulk density, water holding capacity, microbial biomass carbon, substrate-induced respiration, alkaline phosphatase and fluorescein diacetate hydrolytic activities. Vegetable concentrations of heavy metal appeared in the order Zn > Pb > Cu > Ni > Cd and were maximum in leaves (spinach and amaranths) followed by fruits (tomato and egg plant) and minimum in roots (carrot and radish). Multiple regression analysis indicated that the major contribution of most heavy metals to vegetable leaves was from atmosphere. For roots however, soil appeared to be equally important. The study suggests that if the present trend of atmospheric deposition is continued, it will lead to a destabilizing effect on this sustainable agricultural practice and will increase the dietary intake of toxic metals.     

Synthesis and pesticidal activity of new N-alkyl-N-[1-(2-hydroxyphenyl) ethyl]amines

A series of novel N-alkyl-N-[1-(2-hydroxyphenyl) ethyl]amines were synthesized as potential new agents to control pests. Their structures were confirmed on the basis of IR, NMR and elemental analyses. Six new N-alkyl-N-[1-(2-hydroxyphenyl) ethyl]amines were prepared by reduction of corresponding Schiff bases using sodium borohydride in 80–87 % yields. These compounds were tested for their antifungal activity against two pathogenic fungi viz., Rhizoctonia bataticola ITCC 0482 and Sclerotium rolfsii ITCC 5226 and for insecticidal activity against insects of stored grain pest Callosobruchus analis. Fungicidal bioassay revealed that compound N-Decyl-N-[1-(2-hydroxyphenyl)ethyl]amine, was highly effective against R. bataticola (ED₅₀ 6.86 mg L^?1) which was comparable with that of commercial fungicide hexaconazole (ED₅₀ 6.35 mg L^?1). Also compounds N-Heptyl-N-[1-(2-hydroxyphenyl)ethyl]amine, N-Octyl-N-[1-(2-hydroxyphenyl)ethyl]amine and N-Nonyl-N-[1-(2-hydroxyphenyl)ethyl]amine displayed promising fungitoxicity against same pathogen. However, compound N-Heptyl-N-[1-(2-hydroxyphenyl)ethyl]amine was also found to be effective against S. rolfsii (ED₅₀ 4.92 mg L^?1 as against 1.27 mg L^?1 for hexaconazole). Compound N-Hexyl-N-[1-(2-hydroxyphenyl)ethyl]amine was most effective as insecticide followed by compound N-Octyl-N-[1-(2-hydroxyphenyl)ethyl]amine. LC₅₀ values for these compounds were 155.0 and 275.0 mg L^?1 respectively as against 36.70 mg L^?1 for commercial insecticide dichlorovos. The results obtained from bioassays indicate that this class of compounds can be utilized for the design of new substances endowed with pesticidal activities.     

Seasonal changes in plasma calcium and inorganic phosphate levels in relation to parathyroid structure of the grey quail, Coturnix coturnix coturnix Linnaeus

Plasma Ca concentration (annual mean) in males Coturnix cotumix coturnix was 10.27 +/- 0.14 mg/100 ml while it was slightly higher (11.85 +/- 0.15 mg/100 ml) among females. Plasma Pi levels (annual mean) in males and females were 5.62 +/- 0.12 mg/100 ml and 6.52 +/- 0.20 mg/100 ml, respectively. While the males did not exhibit marked fluctuation in plasma Ca and Pi levels either in winter or summer, the females did record significant elevation in the levels of both these electrolytes during breeding season. The peak values of plasma Ca (17.66 +/- 0.38 mg/100 ml) and Pi (8.64 +/- 0.22 mg/100 ml) in females were observed during June. Parathyroid gland of the grey quail exhibited hyperactivity (hypertrophy and hyperplasia) during breeding season, however, the activity was more conspicuous among females than in males. The maximum increase in cell and nuclear diameters were observed in females during May-July. The follicles were also filled with AF- and PAS-positive materials during these months. The glands depicted signs of hypoactivity and degeneration during peak winter season (November-December) as evident by decrease in cell and nuclear diameters as well as vacuolation in the chief cells.     

Soil dehydrogenase, phosphomonoesterase and arginine deaminase activities in an insecticide treated groundnut (Arachis hypogaea L.) field

Chlorpyrifos (O,O-diethyl O-3,5,6-trichloro-2 pyridyl phosphorothioate) 20 EC and Quinalphos (O,O-diethyl O-quinoxalin-2-yl phosphorothioate) 25 EC, were applied in groundnut (Arachis hypogaea L.) field as seed treatment at 25 ml/kg and soil treatment at 4 l/ha in 1998 and 1999. The residues of these insecticides were monitored during the entire crop season and their effect on the soil enzymes dehydrogenase, phosphomonoesterase and arginine deaminase were studied. Ninety nine percent of chlorpyrifos residues were dissipated within 60 days from seed treated soil and 98% dissipation was observed in soil treated field for the same days. Its half lives in seed treated soil were 8 days and 7 days and in soil treated field were 9.2 days in and 7.5 days in 1998 and 1999 respectively. Dissipation of quinalphos in comparison to chlorpyrifos was slow both in seed treated and soil treated field. Eighty seven percentage to 92% dissipation of quinalphos residues were observed from seed treated soil and 98% residues were dissipated from soil treated field within 75 days. Its half lives in seed treated soil were 20 days and 18 days and in soil treated field, its half lives were 13 days and 17 days 1998 and 1999 respectively. Inhibition in dehydrogenase activity followed by recovery was observed both in seed and soil treatments with chlorpyrifos. An inhibition of 17.2% was estimated after 60 days of seed treatment in comparison to control. Dehydrogenase activity was significantly reduced to 63% after 15 days of quinalphos seed treatment in comparison to control in 1998. Similar trends were observed in 1999. A significant inhibition in dehydrogenase activity was observed after soil treatment both in 1998 and 1999. Phosphomonoesterase activities were significantly inhibited upto 25.2% as compared to the control, on the 15th day of chlorpyrifos seed treatment in 1998 and similarly, after one day of treatment in 1999. Quinalphos inhibited the phosphomonoesterase activity till the end of the experimental period in the soil treated fields, whereas recovered within 30-60 days of treatment in the seed treated fields. Arginine deaminase activity was significantly stimulated within one day after chlorpyrifos seed and soil treatments in both years. The activity was almost threefold higher on the 30th and the 15th day of soil treatment in 1998 and 1999, respectively. A temporary inhibition of arginine deaminase activity was observed after quinalphos treatment. It was observed that in most of cases insecticides have temporary inhibitory effect on soil enzymes. However, inhibition was smaller in seed treated soil than in direct soil treatment.     

Microbial biomass, P-nutrition, and enzymatic activities of wheat soil in response to phosphorus enriched organic and inorganic manures

Compost was prepared from wheat straw enriched with Rajasthan rock phosphate and Aspergillus awamori. The resulting phospho-compost along with phosphorus enriched FYM, mineral fertilizer (rock phosphate) and super phosphate were evaluated for their individual contribution in improving organic matter status, P availability, and enzymatic activities of soil under wheat crop grown in a micro plot. The results showed that total organic carbon, nitrogen, microbial biomass, and humus content (an index of organic matter status of soil) of soil was highest when farm yard manure (FYM) after its enrichment with 12.5% rock phosphate was applied. Microbial enriched phospho-compost was the product yielding highest soil available phosphorus, phosphorus uptake, urease, and cellulase activities. However, FYM amended with 25% rock phosphate resulted in the greatest enhancement of beta- glucosidase. Measured parameters indicated a sure improvement of chemical and biological activities of soil after the application of phosphorus enriched organic amendments compared to the commercial fertilizer commonly used by the Indian farmers.