Ultramafic geoecology of South and Southeast Asia

Globally, ultramafic outcrops are renowned for hosting foras with high levels of endemism, including plants with specialised adaptations such as nickel or manganese hyperaccumulation. Soils derived from ultramafic regoliths are generally nutrient-deficient, have major cation imbalances, and have concomitant high concentrations of potentially phytotoxic trace elements, especially nickel. The South and Southeast Asian region has the largest surface occurrences of ultramafic regoliths in the world, but the geoecology of these outcrops is still poorly studied despite severe conservation threats. Due to the paucity of systematic plant collections in many areas and the lack of georeferenced herbarium records and databased information, it is not possible to determine the distribution of species, levels of endemism, and the species most threatened. However, site-specific studies provide insights to the ultramafic geoecology of several locations in South and Southeast Asia. The geoecology of tropical ultramafic regions differs substantially from those in temperate regions in that the vegetation at lower elevations is generally tall forest with relatively low levels of endemism. On ultramafic mountaintops, where the combined forces of edaphic and climatic factors intersect, obligate ultramafic species and hyperendemics often occur. Forest clearing, agricultural development, mining, and climate change-related stressors have contributed to rapid and unprecedented loss of ultramafic-associated habitats in the region. The geoecology of the large ultramafic outcrops of Indonesia’s Sulawesi, Obi and Halmahera, and many other smaller outcrops in South and Southeast Asia, remains largely unexplored, and should be prioritised for study and conservation

Demographical characterization of dengue infected patients in Akurana medial officer of health area, central Province of Sri Lanka.

Dengue has been recognized to be one of the major threats on the public health of many tropical countries including Sri Lanka. Controlling of the high rate of mortality caused by dengue, which remains without being altered regardless of the immense efforts and control strategies of the relevant authorities, has remained as a major challenge for the Sri Lankan health sector. Vulnerability assessment of communities to dengue infection is of higher importance in drafting and implementation of management plans to ensure effective management and controlling of dengue epidemics at the regional scale. Therefore, a statistic based analysis of the dengue patient characteristics was carried out to determine the susceptibility of population to dengue infection in Akurana Medical Officer of Health (MOH) area. Monthly records of reported dengue cases from 2010 to 2014 of the Akurana MOH division were collected. Normal Chi square test coupled with Paired-Chi square test was devised to investigate the impact of sex and age on the infection. MINITAB (version 14.12.0) software package was used for statistical analysis. In accordance with the results of the normal Chi square test, the Percentage Infected Male: Female Ratio (PIMFR) remains significantly altered throughout the period of study (p=0.001 61 (1.84%). However, according to the Paired-Chi square test, the vulnerability of age groups tend to shift significantly throughout the study period [>Χ2 (7, 0.95) = 14.067]. In conclusion males tend to indicate relatively high susceptibility to dengue. Age groups of 6 - 10, 11 - 20 and 21 - 30 could be recognized as highly vulnerable age groups in the community for dengue, while age group of >61 emerge as the least vulnerable age group for the infection of dengue in the Akurana MOH.Financial assistance from the National Research Council Funded Dengue Mega Project (NRC TO 14-04)

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

Biomass estimation in some dry zone forests in Sri Lanka from Forest Inventory Data

Tropical forests are a major sink for carbon dioxide produced globally. Estimation of above-groundbiomass of these forests is an essential aspect of studies of carbon stocks and the effects of carbon sequestration on the global carbon balance. Long term monitoring plots across several tropical dryevergreen forests in India, in the recent past, shows they are highly carbon dense ranging from 73.06Mg ha-1 to 173.1 Mg ha1. In Sri Lankan forests, biomass estimates are confined to the wet zone forestsand plantations.To assess the carbon dynamics in Sri Lankan dry zone forests, as a pilot study, above-ground biomass infive dry zone forests were estimated using past forest inventory data from 1961. Our objective was todevelop an above-ground carbon database for dry zone forests, which can be used to determine the carbon dynamics in those forests. The data of published stand and stock tables from the five dry zoneforests, Hurulu, Kumbukkan, Kantalai, Pallekelle and Madhu, were converted to above ground biomassusing published allometric models. Estimated above-ground biomass ranged from a minimum of 75.7Mg ha-1 in the Kumbukkan forest to a maximum of 129.6 Mg ha-1 in the Kantalai forest. The total abovegroundcarbon stocks ranged from 37.8 Mg ha-1 in the Kumbukkan forest to a maximum of 64.8 Mg ha-1 inthe Kantalai forest. The average above-ground biomass for dry zone forests was 92.62 Mg ha-1. Whencompared with the wet zone estimates (eg.Sinharaja 336.8 Mg ha-1) the dry zone forests have lowerabove-ground biomass due to high disturbances, low tree density and other factors such as slow growthpattern of most of the tree species. However, present above-ground biomass estimates are not availablefor dry zone forests and estimates from this study can be considered as the above-ground carbon stock1960’s. These estimates shall be presented to assess the carbon dynamics in dry zone forests of SriLanka

Growth and nickel uptake by serpentine and non–serpentine populations of Fimbristylis ovata (Cyperaceae) from Sri Lanka

Compared with serpentine floras of Southeast Asia, the serpentine vegetation of Sri Lanka is impoverished in regard to serpentine endemics and nickel hyperaccumulators. All species so far documented from the serpentine outcrops of Sri Lanka also have non-serpentine populations; it is unclear whether the serpentine populations are physiologically distinct and deserve ecotypic recognition. We conducted a preliminary study to examine whether serpentine and non-serpentine populations of Fimbristylis ovata represent locally adapted ecotypes by investigating their growth and potential for nickel uptake and tolerance under greenhouse conditions. Although both populations of F. ovata showed a similar growth pattern in serpentine soil during short-term exposure (21 days), the non-serpentine population was unable to survive in serpentine soil under long-term exposure (4 months). Both populations were able to uptake nickel from serpentine soil during short-term exposure (21 days). The serpentine population, however, translocated significantly more nickel from its roots to shoots (translocation factor 0.43) than the non-serpentine population (translocation factor 0.29). Our preliminary investigations suggest that the serpentine and non-serpentine populations of F. ovata may be locally adapted to their respective soils. However, additional studies are required to determine whether the populations deserve ecotypic recognitio

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

Growth and Nickel Uptake by Serpentine and Non-Serpentine Populations of \u3ci\u3eFimbristylis ovata\u3c/i\u3e (Cyperaceae) From Sri Lanka

Compared with serpentine floras of Southeast Asia, the serpentine vegetation of Sri Lanka is impoverished in regard to serpentine endemics and nickel hyperaccumulators. All species so far documented from the serpentine outcrops of Sri Lanka also have non-serpentine populations; it is unclear whether the serpentine populations are physiologically distinct and deserve ecotypic recognition. We conducted a preliminary study to examine whether serpentine and non-serpentine populations of Fimbristylis ovata represent locally adapted ecotypes by investigating their growth and potential for nickel uptake and tolerance under greenhouse conditions. Although both populations of F. ovata showed a similar growth pattern in serpentine soil during short-term exposure (21 days), the non-serpentine population was unable to survive in serpentine soil under long-term exposure (4 months). Both populations were able to uptake nickel from serpentine soil during short-term exposure (21 days). The serpentine population, however, translocated significantly more nickel from its roots to shoots (translocation factor 0.43) than the non-serpentine population (translocation factor 0.29). Our preliminary investigations suggest that the serpentine and non-serpentine populations of F. ovata may be locally adapted to their respective soils. However, additional studies are required to determine whether the populations deserve ecotypic recognition

Atividade antimicrobiana de óleos essenciais no controle de alguns fitopatógenos fúngicos in vitro e no tratamento de sementes Antimicrobial activity of essential oils on the in vitro control of some fungal phytopathogens and on seed treatment

Este trabalho verificou o efeito dos óleos essenciais (OE) extraídos de Eremanthus erythropappus (candeia), Cymbopogon martinii (palmarosa) e de Rosmarinus officinalis (alecrim) no crescimento micelial de alguns fitopatógenos fúngicos e no tratamento de sementes de milho, soja e feijão. No teste in vitro, alíquotas de 20, 40, 60, 100, 200, 500 e 1000 &#956;L de cada um dos óleos essenciais foram distribuídas na superfície do meio de cultura. Posteriormente, discos de meio de cultura com micélio de Alternaria carthami, Alternaria sp. e Rhizoctonia solani foram transferidos para o centro de cada placa. O crescimento foi mensurado e calculada a taxa de inibição do crescimento micelial (ICM). Para verificar o efeito dos OE na germinação das sementes utilizou-se a aplicação deles por fumigação. Foi avaliada a percentagem de sementes germinadas e a incidência de patógenos nas sementes. Sobre o crescimento micelial, o óleo de palmarosa inibiu completamente todos os patógenos fúngicos, independentemente da concentração. Já os óleos de candeia e alecrim foram melhores quando foram adicionadas alíquotas superiores a 200 &#956;L. Os óleos influenciaram diferentemente a germinação e a sanidade das sementes de milho, soja e feijão.<br>This study aimed to verify the effect of essential oils (EO) extracted from Eremanthus erythropappus ("candeia") Cymbopogon martinii ("palmarosa") and Rosmarinus officinalis (rosemary) on the mycelial growth of some fungal phytopathogens, as well as on the treatment of corn, soybean and bean seeds. In the in vitro test, aliquots of 20, 40, 60, 100, 200, 500 and 1000 &#956;L of each essential oil were distributed on the surface of the culture medium. Then, discs of culture medium with mycelium of Alternaria carthami, Alternaria sp and Rhizoctonia solani were transferred to the center of each plate. Growth was measured and the mycelial growth inhibition rate (MGI) was calculated. To verify the effect of EO on seed germination, application of oils was by means of fumigation. Percentage of germinated seeds and their incidence of pathogens were evaluated. For mycelial growth, "palmarosa" oil completely inhibited all fungal pathogens, regardless of the concentration. On the other hand, "candeia" and rosemary oils were better when aliquots higher than 200 &#956;L were added. The oils differently influenced the germination and health of corn, soybean and bean seeds