Seed dormancy of Cardiospermum halicacabum (Sapindaceae) from three precipitation zones in Sri Lanka.

This study investigated seed germination of Cardiospermum halicacabum, a medicinally important invasive species. We compared mass, moisture content (MC), dormancy and dormancy-breaking treatments and imbibition and germination of scarified and non-scarified seeds of C. halicacabum from a low-elevation dry zone (DZ), low-elevation wet zone (WZ1) and mid-elevation wet zone (WZ2) in Sri Lanka to test the hypothesis that the percentage of seeds with water-impermeable seed coats (physical dormancy, PY) decreases with increased precipitation. Seed mass was higher in WZ2 than in DZ and WZ1, while seed MC did not vary among the zones. All scarified DZ, WZ1 and WZ2 and non-scarified DZ and WZ1 seeds imbibed water, but only a few non-scarified WZ2 seeds did so. When DZ and WZ1 seeds were desiccated, MC and percentage imbibition decreased, showing that these seeds have the ability to develop PY. GA3 promoted germination of embryos excised from fresh DZ and WZ1 seeds and of scarified WZ2 seeds. At maturity, seeds from DZ and WZ1 had only physiological dormancy (PD), while those from WZ2 had combinational dormancy (PY+PD). Thus, our hypothesis was not supported. Since a high percentage of excised embryos developed into normal seedlings; this is a low-cost method to produce C. halicacabum plants for medicinal and ornamental purposes.

Assessment of Airborne Bacterial and Fungal Communities in Selected Areas of Teaching Hospital, Kandy, Sri Lanka.

Nosocomial infections, in lay term known as hospital acquired infections, are caused mainly by airborne pathogens found in healthcare facilities and their surroundings. The aim of this study was to quantify and identify bacteria and fungi in a hospital, which is an understudied area of air quality in Sri Lanka. Air samples were collected in agar medium and petri plates containing sterile filter papers. The number of culturable and total airborne microorganisms was estimated by manual counting and fluorescent microscopy, respectively. The morphologically distant bacteria and fungi were identified by DNA sequencing. The statistical analysis revealed significant variances between studied sites (p < 0.05) where Outpatients Department and Respiratory Unit showed higher levels of airborne microbial load. Culturable microbial count was higher at noon (hospital visiting hours) compared to other sampling periods (after hospital visiting hours) within the hospital. Total count of airborne microbes was found to be the highest during the afternoon. The most sensitive zones such as Operating Theatre and Intensive Care Unit showed considerably higher counts of airborne microbes. Identification by molecular means revealed the presence of human pathogens in the hospital air including Bacillus sp, Micrococcus sp, Pseudomonas sp, Staphylococcu ssp, Exiguobacterium sp, Enterobacter sp, Escherichia sp, Sphingomonas sp, Massilia sp, Kocuria sp, Fusarium sp, and Aspergillus sp. In conclusion, the results from this study indicate that the hospital air was generally contaminated. Therefore, the implementation of proactive policies and strategies are needed to monitor hospital air quality in sensitive zones as well as other areas of the hospitals.

Microorganisms and heavy metals associated with atmospheric deposition in a congested urban environment of a developing country: Sri Lanka.

The presence of bacteria and heavy metals in atmospheric deposition were investigated in Kandy, Sri Lanka, which is a typical city in the developing world with significant traffic congestion. Atmospheric deposition samples were analyzed for Al, Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb which are heavy metals common to urban environments. Al and Fe were found in high concentrations due to the presence of natural sources, but may also be re-suspended by vehicular traffic. Relatively high concentrations of toxic metals such as Cr and Pb in dissolved form were also found. High Zn loads can be attributed to vehicular emissions and the wide use of Zn coated roofing materials. The metal loads in wet deposition showed higher concentrations compared to dry deposition. The metal concentrations among the different sampling sites significantly differ from each other depending on the traffic conditions. Industrial activities are not significant in Kandy City. Consequently, the traffic exerts high influence on heavy metal loadings. As part of the bacterial investigations, nine species of culturable bacteria, namely; Sphingomonas sp., Pseudomonas aeruginosa, Pseudomonas monteilii, Klebsiella pneumonia, Ochrobactrum intermedium, Leclercia adecarboxylata, Exiguobacterium sp., Bacillus pumilus and Kocuria kristinae, which are opportunistic pathogens, were identified. This is the first time Pseudomonas monteilii and Ochrobactrum intermedium has been reported from a country in Asia. The culturable fraction constituted ~0.01 to 10%. Pigmented bacteria and endospore forming bacteria were copious in the atmospheric depositions due to their capability to withstand harsh environmental conditions. The presence of pathogenic bacteria and heavy metals creates potential human and ecosystem health risk.