Role of Bacterial-Fungal Interactions on Heavy Metal Phytotoxicity in Serpentine Soil

This study was conducted to understand the role of bacterial–fungal interactions on heavy metal uptake by Zea mays plants. A pot experiment was conducted for 90 days with Z. mays in serpentine soil inoculated with a Gram-negative bacterium, fungus (Aspergilllus sp.) and both microbes to determine the effects of inoculation on nickel, manganese, chromium and cobalt concentrations in plant tissue and soil. Soil nutrients and soil enzyme activities were measured to determine the effect of inoculations on soil quality. Inoculation of microorganisms increased shoot and root biomass, and the maximum biomass was in the bacterial–fungal inoculation. This could be due to the solubilisation of phosphate and production of indole acetic acid. Although the combination treatment contributed to an increase in heavy metal uptake in Z. mays plants, the lowest translocation was observed in the combination treatment. Moreover, the soil available nitrogen, available phosphorous and total organic carbon content were increased with the microbial inoculation. Similarly, the soil dehydrogenase activity was higher as a result of microbial inoculation, whereas the highest dehydrogenase activity was reported in the combination inoculation. This study confirms the synergistic effect of bacterial–fungal inoculation as a soil-quality enhancer and as a plant-growth promoter in the presence of heavy metals

Long term control of corrosion of steel reinforcement by a two-stage cathodic protection method

It has been shown experimentally that corrosion of steel reinforcement can be arrested if sufficient cathodic charge at a current density higher than 20 mA/m2 is applied over a period of weeks. Once corrosion is arrested, a cathodic prevention current density, which requires a current density an order of magnitude lower than for conventional cathodic protection, can be applied for long-term prevention of re-initiation of corrosion. Self-contained products were developed in the laboratory according to the Two-Stage principle, each single product containing a battery-operated ICCP element which produces a high initial current output of between 20 mA/m2 and 50 mA/m2 of steel area during an initial polarisation corrosion arrest phase and a galvanic anode component which delivers the lower cathodic prevention current long-term. Diodes ensure that the current from the battery is delivered to the steel reinforcement and not dumped onto the galvanic anode and allow the galvanic current to flow only when the ICCP element becomes inoperable. This paper describes the principles of the technique, illustrates products developed and presents medium-term field studies to demonstrate the success of the Two-Stage CP technique

A preliminary study of the role of bacterial-fungal co-inoculation on heavy metal phytotoxicity in serpentine soil

This study was conducted to understand the role of bacterial–fungal interactions on heavy metal uptake by Zea mays plants. A pot experiment was conducted for 90 days with Z. mays in serpentine soil inoculated with a Gram-negative bacterium, fungus (Aspergilllus sp.) and both microbes to determine the effects of inoculation on nickel, manganese, chromium and cobalt concentrations in plant tissue and soil. Soil nutrients and soil enzyme activities were measured to determine the effect of inoculations on soil quality. Inoculation of microorganisms increased shoot and root biomass, and the maximum biomass was in the bacterial–fungal inoculation. This could be due to the solubilisation of phosphate and production of indole acetic acid. Although the combination treatment contributed to an increase in heavy metal uptake in Z. mays plants, the lowest translocation was observed in the combination treatment. Moreover, the soil available nitrogen, available phosphorous and total organic carbon content were increased with the microbial inoculation. Similarly, the soil dehydrogenase activity was higher as a result of microbial inoculation, whereas the highest dehydrogenase activity was reported in the combination inoculation. This study confirms the synergistic effect of bacterial–fungal inoculation as a soil-quality enhancer and as a plant-growth promoter in the presence of heavy metal

Probing into the concept of ‘research for society’ to utilize as a strategy to synergize flexibility of a research institute working on eco-friendly commercial agriculture

Research and Development work on Commercial Agriculture (CA) has not sufficiently been taken into account of those transformations occurring in the country’s socio-economic and political environment, especially in the lens of decision-making and adoption of eco-friendly technologies in CA. It has been debated for a long time that well-set strategic policies and guidelines incorporated and agreed upon by all stakeholders into a model possess a vast potential to facilitate such decision-making towards the establishment of an eco-friendly CA. In the light of that, an illustrative model was built of which the logical paths were characterized by the variables stand for Key Performance Drives (KPD) to exhibit the state of societal acceptance of the research outputs on the concept of ‘Research for Society’ within the realm of functional flexibility of research institutes. The outputs and outcomes from such an exploratory analysis would facilitate research institutes working on CA to systematically adopt the ‘best-fit KPDs’ in research development and researches to be conceived from societal roots. Further, it would establish the true connections and dependencies between research, social awareness of research needs, and flexibility of research institutes to enhance the performance of the sector, through collected data on Key Performance Indicators (KPI)

Role of Woody Biochar and Fungal-Bacterial Co-Inoculation on Enzyme Activity and Metal Immobilization in Serpentine Soil

Purpose In this study, we investigated the effect of biochar (BC) and fungal bacterial co-inoculation (FB) on soil enzymatic activity and immobilization of heavy metals in serpentine soil in Sri Lanka. Materials and methods A pot experiment was conducted with tomatoes (Lycopersicon esculentum L.) at 1, 2.5, and 5 % (w/w) BC ratios. Polyphenol oxidase, catalase and dehydrogenase activities were determined by idometric, potassium permanganate oxidisable, and spectrophotometric methods, respectively. Heavy metal concentrations were assessed by 0.01 M CaCl2 and sequential extraction methods. Results and discussion An increase in BC application reduced polyphenol oxidase, dehydrogenase, and catalase activity. The application of FB increased soil dehydrogenase activity, with the maximum activity found in 1 % BC700 + FB treatment. Moreover, the CaCl2 extractable metals (Ni, Mn, and Cr) in 5 % BC700 amended soil decreased by 92, 94, and 100 %, respectively, compared to the control. Sequential extraction showed that the exchangeable concentrations of Ni, Mn, and Cr decreased by 55, 70, and 80 % in 5 % BC700, respectively. Conclusions Results suggest that the addition of BC to serpentine soil immobilizes heavy metals and decreases soil enzymatic activities. The addition of FB to serpentine soil improves plant growth by mitigating heavy metal toxicity and enhancing soil enzymatic activities

Population : 1984 and beyond.

Critical issuesPopulation distribution and migration: the impact on national development plans / Gamini SeneviratneMortality and health policy: a measure for development / Margaret E. JonesFertility and the family: changing conditions and perceptions / Rami ChhabraPopulation, resources, environment and development: issues on interrelationships / Ian Steel