Browsing by Author "Seneviratne, K. L"

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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.
Open Access
Recent progress in visible-light active (VLA) TiO2 nano-structures for enhanced photocatalytic activity (PCA) and antibacterial properties: a review
(Islamic Azad University, Shahreza Branch, 2021-09-01) Seneviratne, K. L; Munaweera, I; Peiris, S; Peiris, C. N; Kottegoda, N
The applications of photocatalytic nanomaterial technology received intense scientific focus with the advent of nanotechnology. Applications based on TiO2 nanoparticles have shown promise of photocatalytic efficiency among many semiconductor metal oxides. Titanium dioxide is utilized in many practical applications such as water and air purification, self-cleaning of surfaces, and energy production. The major drawback with TiO2 based photocatalysts is the wide band gap, which requires UV light to produce the electron-hole pairs. This review article focus on techniques/methods to eliminate band gap which reduces photocatalytic efficiency. Application of semiconductor photocatalytic techniques to degrade organic pollutants and their antimicrobial activity is discussed here using model systems. Synthetic and natural nanohybrids are available today and have varying characteristics as options. Recently developed natural mineral based nanohybrids is the new trend in photocatalytic applications. It appears that the removal efficiency of existed photocatalysts is higher than that of synthetic products. Natural nanohybrids carry the advantages of low costs, avoiding extensive synthesizing conditions in future photocatalytic applications.
Embargo
A Successful Surface Sterilization Technique for in vitro Establishment of Dracaena sanderiana Sander ex Mast. Nodal Explants
(Faculty of Humanities and Sciences,SLIIT, 2021-09-25) Seneviratne, K. L; Malwattage, G; Weerakkody, G. K; Peiris, S. E; Peiris, C. N
Dracaena sanderiana Sander ex Mast. is the number one cut foliage exported from Sri Lanka and it is also a popular potted plant. In order to promote dracaena cultivation, micropropagation techniques can be employed to produce high quality large number of clones as planting materials. However, severe microbial contaminations in the in vitro establishment stage mitigate the micropropagation application on this species. Therefore, this study was undertaken with the objective of using silver nitrate (AgNO3) to eliminate surface adhered microorganisms to obtain high amount of contamination free cultures at the in vitro establishment stage. Investigations also carried out to explore reusability of AgNO3 after the first wash in surface sterilization. Apical parts of about 8 cm of D. sanderiana cv ‘White’ were used in this study. Silver nitrate solution in 200 mg/L and Clorox™ in 10% concentrations were used for the surface sterilization of the nodal explants. Results revealed that 200 mg/L AgNO3 produced 90% and 10% Clorox produced 20% contamination free cultures after 8 weeks of establishment in vitro. Also, in the experiment of investigation of reusability of AgNO3 it was observed that the second and third washings of AgNO3 produced 80 and 70% non-contaminated cultures, respectively. Results of this study suggest that AgNO3 is a highly effective low-cost non-toxic material which can be used in surface sterilization of D. sanderiana nodal explants. With this promising results it can be suggested that 200 mg/L AgNO3 solution can be considered to replace toxic heavy metals such as mercuric chloride frequently used in Micropropagation.