Browsing by Author "Peiris, S.E"

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Embargo
Effects of Coconut Water on Micropropagation of Caladium Bicolour Cv ’Thai Beauty’
(Faculty of Humanities and Sciences, SLIIT, 2022-09-15) Ratnayake, R.D; Peiris, S.E; Malwattage, G; Peiris, C.N
Caladium bicolour (Aiton) Vent. is an attractive commercial ornamental plant in the horticulture industry which is popular as potted plants for homescaping and as garden plants for landscaping. Propagation of this attractive plant through micropropagation has more benefits than conventional propagation. The current study describes an in vitro multiplication of Caladium bicolour cv ‘Thai Beauty’ with coconut water as a supplement. Shoots derived from leaf explants were cultured on Murashige and Skoog (MS) medium supplemented with 0, 0.5, 1 and 1.5 mg/L (6- Benzylaminopurine) with and without 120 mL/L of coconut water. The results showed that coconut water (CW) with 0.5 and 1.5 mg/L BAP in the medium increased caladium shoot multiplication having an average of 6.67 and 7.75 shoots /shoot, respectively, with a large number of high-quality shoots. Coconut water alone in the medium also produced average of 3.42 shoots/ shoot. Hence, the current protocol provides a direct, cost-effective mass propagation method for large-scale commercial cultivation of caladium.
Open Access
Green Synthesis, Characterizati on of Cu Nano Units and Evaluati on of Anti bacterial Properti es towards the Bacterial Blight Control in Anthurium andraeanum Lind under In-vitro and In-vivo Conditions
(Faculty of Humanities and Sciences, SLIIT, 2024-12-04) Wanaguru, S; Peiris, C.N; Peiris, S.E; Jayasinghe, S
Most types of metal nanoparti cles exhibit anti bacterial properti es. Copper nanoparti cles can generate reacti ve oxygen species (ROS) within bacterial cells, initi ati ng a cascade of events that lead to bacterial cell death. In this study, copper nano units (Cu NUs) were synthesized through green synthesis method using anthurium leaf extract toward the control of bacterial blight disease in Anthurium andraeanum cv ‘Rainbow’ plants. Synthesized Cu NUs were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diff racti on (XRD) techniques. Anti bacterial properti es of 30, 50 and 100 ppm of Cu NUs against Xanthomonas sp. which cause bacterial blight in anthurium plants were studied under invitro conditi ons using well diff usion test. Moreover, anti bacterial properti es of said NUs were studied at in-vivo levels by spraying Cu NUs at concentrati ons of 50, 100 and 200 ppm on bacterial blight infected anthurium cv ‘Rainbow. According to SEM and TEM analysis, synthesized NUs remained within size of 25.36 ± 12.55 nm length and 16.18 ± 3.75 nm width exhibiti ng a polygonal shape. In well diff usion test, opti mized 30 ppm concentrati on of Cu NUs formed an inhibiti on zone with a diameter of 20.6 ± 0.94 mm. In comparison, the anti bioti c sulfamethoxazole (positi ve control) formed an inhibiti on zone with a diameter of 26.3 ± 0.47 mm. At in-vivo level, 200, 100 and 50 ppm all three concentrati ons were able to control disease in 90% of treated plants within 5, 6 and 7 weeks respecti vely. Overall, this research highlights the potenti al of Cu NUs as an eff ecti ve alternati ve for controlling bacterial blight disease in anthurium cv ‘Rainbow’.
Embargo
In Vitro Antibacterial Activity of Sulphur Nanoparticles as a Possible Application to Control Bacterial Blight Caused by Xanthomonas spp. in Anthurium
(Faculty of Humanities and Sciences, SLIIT, 2022-09-15) Peiris, S.E; Malwattage, G; Ratnayake, R. D; Seneviratne, K .L; Peiris, C.N
Anthurium blight is caused by Xanthomonas spp. which is regarded as the most threatening disease to the anthurium industry worldwide. Therefore, the current study was carried out to determine whether the application of sulphur nanoparticles (SNPs) is a possible solution for treating anthurium cultivars infected with Xanthomonas spp. The bacterium Xanthomonas was isolated using standard methods and a single bacterial colony was isolated using nutrient agar. The colonies were identified as Xanthomonas spp as they were gram-negative, motile rods due to the colony characters like yellow color because of the xanthin produced. The symptoms appeared in the pathogenicity test which was carried out by injecting purified Xanthomonas sp. into disease free anthurium plants confirmed the identification of the bacterial strain. Time-kill assay was conducted using Staphylococcus aureus, Escherichia coli and isolated Xanthomonas spp to investigate the behavior of SNPs. The results showed that suspension treated with 1g of SNPs for 30 minutes inhibited growth of Staphylococcus aureus colonies showing mean number of 7.92 CFU/ml compared to the control (mean number of colonies 9.09 CFU/ml ) treatment following 12 hours incubation. However, Escherichia coli, and isolated gram-negative rods (Xanthomonas spp) did not show positive influence for SNPs when compared to the control treatment. Therefore, further investigation is required to reach firm conclusions about this matter because the antimicrobial activity of SNPs varies depending on the type of target microorganisms, method and solvent used to dissolve SNPs.
Open Access
Living Colours: Development of Microbial Culture Collection for Use as Microbial Colour Pigments in Textile Dyes
(Faculty of Humanities and Sciences, SLIIT, 2023-11-01) Hewagama, H.L; Somarathna, G.M.T.K.; Herath, L.; Peiris, S.E
The textile industry is one of the largest worldwide polluters of clean water due to the heavy use of synthetic dyes. Synthetic dyes are harmful to aquatic life and to human health. To overcome this, natural dyes are being explored as a healthier and more eco-friendly alternative. Several advantages such as ease of extraction, availability, high yields and no seasonal variation make microbial pigments the most ideal source of natural pigments. This study was done to isolate colour pigment producing bacteria and fungi from soil collected from organic farms from various locations in Sri Lanka. In total, 9 pigment producing bacteria and 3 pigment producing fungi were isolated. Gause’s synthetic agar yielded the most pigmented isolates. Extracellular pigments produced by 5 of the bacterial isolates were extracted by a waterbased method. The antibacterial activity of the pigments in their crude and concentrated forms was tested using the well diffusion method against E.coli ATCC 8739 and Staphylococcus aureus ATCC 6538P. Inhibition zone against S.aureus was observed for both crude (12.33±0.58mm) and concentrated pigments (9.67±0.58mm) extracted from purple pigment producing bacterial isolate (BPU). This pigment has the potential to be used in antibacterial textile preparation. Extracted pigments were used to dye scoured cotton fabric with the use of 3% alum as mordant. Pigment from BPU isolate resulted in better coloured fabric.
Open Access
A Novel Surface Sterilization Technique for in vitro Establishment of Dianella tasmanica variegata Nodal Explants
(researchgate.net, 2021-12) Malwattage, G; Ratnayake, R. D; Seneviratne, K. L; Peiris, S.E; Peiris, B. C. N
Dianella tasmanica ‘variegata’ is one of the popular species which is exported as ex-agar plants from Sri Lanka. In order to promote dianella exports, micropropagation should be increased to produce a high-quality large number required by the export markets. However, severe microbial contaminations in the in vitro establishment have become the bottle neck for large scale in vitro propagation of this species. Therefore, this study was undertaken with the objective of using sulfur nanoparticles (S-NP) to eliminate surface adhered fungal and bacterial contaminants to obtain a vast number of contamination-free cultures at the in vitro establishment stage. Apical parts of about 6 cm of D. tasmanica were used in this study. Effects of S-NP solution in 500 mg/L was used with the control of 10% Clorox™ for the surface sterilization of the nodal explants. Results revealed that 500 mg/L S-NP produced 80% and CloroxTM produced 40% contamination-free cultures after 4 weeks of establishment in vitro. The experiment was repeated twice. This study suggests that S-NP is a promising lowcost non-toxic material that can be used in the surface sterilization of dianella nodal explants.