Browsing by Author "Malwattage, G"

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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.
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
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.
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.