In vitro Evaluation of Growth Inhibition of Some Common Soil Fungi by Selective and Non-selective Herbicides
Ubogu Monday,
Akponah Ejiro,
Ogbaran Dickson Solomon
Issue:
Volume 3, Issue 1, February 2017
Pages:
1-8
Received:
6 September 2016
Accepted:
1 March 2017
Published:
24 March 2017
Abstract: The indiscriminate and excessive use of herbicides being witnessed in recent times portends possible danger to environmental and human health. To gage the likely impacts of herbicides onfungal ecosystem services, the influence of three narrow [selective (atrazine, butachlor and 2,4-D)] and two broad [non-selective (glyphosate and paraquat)] spectrum herbicides at various concentrations of 0, 0.01, 0.1, 0.5 and 1% v/v on the radial mycelial extension growth, mycelial extension growth rate, percentage mycelial growth inhibition and minimum sporulation time of four common soil fungi, Aspergillus niger, A. flavus, Trichoderma viride and Penicillium sp. were investigated on PDA plates for a period of 96 h at 30 ± 2°C (room temperature). The radial mycelial extension growth of fungi decreased with increased concentrations of the herbicides except for T. viride where atrazine did not show any significant difference among all the concentrations tested (P≤0.05). The fastest mycelia extension growth rate for all fungi was recorded in Atrazine at the highest concentration tested, with T. viride being the fastest at 0.44 mm h-1. At 1% v/v, save for atrazine, all the herbicides inhibited at least 66% mycelial growth with 2,4-D showing a 100% inhibition. The minimum sporulation time for all fungi in the presence of the herbicides was 48 h. There was no sporulation in A. flavus and T. viride in presence of paraquat and 2,4-D above 0.1% v/v concentration within the 96 h of investigation. The results of this study suggest that indiscriminate and excessive use of herbicides could negatively affect ecosystem function.
Abstract: The indiscriminate and excessive use of herbicides being witnessed in recent times portends possible danger to environmental and human health. To gage the likely impacts of herbicides onfungal ecosystem services, the influence of three narrow [selective (atrazine, butachlor and 2,4-D)] and two broad [non-selective (glyphosate and paraquat)] spectru...
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Microbiology of Seawater and Sand in a Selected Bathing Site of Sri Lanka – A Study Towards Microbial Quality Assessment
Kaumadi Samarasekera,
Sriyanie Indrika Abeygunawardena
Issue:
Volume 3, Issue 1, February 2017
Pages:
9-18
Received:
6 October 2016
Accepted:
12 January 2017
Published:
8 May 2017
Abstract: The presence of many types of microorganisms, including potential pathogens has been reported as an integral part of coastal management programs in many countries. Therefore the purpose of this study was to examine the seawater collected from a selected bathing site in the West coast of Sri Lanka, for pollution indicating bacterial parameters. Sand samples were subjected to similar evaluation. Two sites were selected from this location to collect samples. The following microbial parameters were analyzed in the collected samples: enterococci, total coliforms, thermotolerant coliforms, E. coli, Pseudomonas sp. and Staphylococcus sp. In addition, physical parameters such as temperature, pH and conductivity were also measured in collected samples. Enterococci counts generally varied from 09 - <1600 (MPN/100 ml). The statistical analysis revealed that counts of enterococci, coliforms, thermotolerent coliforms and E. coli were not significantly different at two sites in both seawater and sand samples. The average enterococci and total coliform counts in beach sand were higher than that of seawater. However, E. coli showed a higher average count as 228 (MPN/100ml) in seawater than 72 (MPN/100 ml) in beach sand. Bacteria belonging to species of Vibrio, Aeromonas, Pseudomonas, Bacillus, Staphylococcus and Listeria were identified from both seawater and sand. The sampled seawater was characterized by a salinity of 20-33 (ppt) and varying pH of 6.7 – 8.20. Based on the obtained results for enterococci, the selected location was provisionally classified in the D category as per WHO guidelines. However microbiological quality of the seawater as per the water quality guidelines depends upon which indicator microbe is chosen.
Abstract: The presence of many types of microorganisms, including potential pathogens has been reported as an integral part of coastal management programs in many countries. Therefore the purpose of this study was to examine the seawater collected from a selected bathing site in the West coast of Sri Lanka, for pollution indicating bacterial parameters. Sand...
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