Faculty of Humanities and Sciences
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Publication Embargo Production of Disease Free Rumohra adiantiformis (Leatherleaf Fern) Using In Vitro Propagation(Faculty of Humanities and Sciences - SLIIT, 2021-03-26) Perera, D.; Peiris, S.E.This study investigated the use of rhizome tips as explants in regenerating disease-free plantlets of Rumohra adiantiformis (G. Frost) using the micropropagation technique. Rhizome tips of 0.5 cm, 1 cm, 1.5 cm, and 2 cm in length, and with and without outer skin were used as explants.The highest regeneration rate (30%) was achieved with an explant size of one centimetre when the outer skin was not present in rhizome explants. Rhizome tips produced complete plantlets in Murashige and Skoog (MS) medium without any growth regulators in 80 - 90 days of culture initiation. In vitro multiplication of disease-free plants was achieved by culturing four months old in vitro plantlets in the MS medium supplemented with 2 mg/L Benzyl Amino Purine (BAP) and 0.1mg/L Naphthalene Acetic Acid (NAA). Plantlets produced clusters of shoot primordia which are known as green globular bodies (GGB) in the multiplication medium, 10 weeks after culturing. Plantlets were obtained by culturing 2-3 mm size GGB segments in the basal medium without any plant growth regulators. Disease indexing of the in vitro derived plantlets verified that at in vitro level 60% of the plantlets obtained from the rhizome tips of one centimetre were free from bacterial and fungal diseases.Publication Embargo Improvement of the Survival Rate of In Vitro Propagated Dendrobium intermediate CV ‘White’ during Acclimatization(Faculty of Humanities and Sciences - SLIIT, 2021-03-26) Isaac, P.N.; Peiris, S.E.Dendrobium intermediate cv 'White', an ornamental plant with exquisite flowers which is produced through In vitro propagation, undergoes hyperhydricity in vitro conditions. As a result, they project a low survival rate during acclimatization which is a bottleneck for its success in micropropagation. This research aimed at overcoming the low survival rate during acclimatization of Dendrobium intermediate cv ‘White’ by improving the medium used in the pre- transplant stage. In vitro seedlings were cultured on Murashige & Skoog (MS) medium, without any growth regulators, with 3 sugar concentrations (3, 4 and 5% (w/v) at the pre-transplant stage for six weeks before being acclimatized in the protected house. After four weeks of acclimatization, the highest survival rate (100%), moderate survival rate (66.7 %) and lowest survival rate (12.5%) were observed in plants grown in vitro in MS medium fortified with 5, 4 and 3% (w/v) sugar concentrations respectively at the pre-transplant stage. Thus, increased sugar levels (5%, w/v) in the pre-transplant stage, can be recommended to achieve a 100% survival rate of Dendrobium intermediate cv ‘White’ during acclimatization. This is a promising solution to facilitate continuous mass production of Dendrobium intermediate cv ‘White’.Publication Embargo Effects of Silver Nitrate in In Vitro Establishment of Cordyline fruticosa (L.) cv ‘Purple Compacta Tri Colour’ with CSUP Media Sterilization(Faculty of Humanities and Sciences - SLIIT, 2021-03-26) Peiris, S.E.; Hemathilaka, H.; Peiris, C.N.; Wijerathna, A.W.Cordyline Varieties have gained high interest in the export markets for the in vitro ex agar plant material. Though in vitro plants have many advantages in export markets required quantities cannot be produced in a given period of time due to the high contamination rates in establishment of explants. Hence, this study was carried out to investigate silver nitrate (AgNO3) in three concentrations, on Cordyline fruticosa cv ‘Purple Compacta Tri Colour’ as an efficient chemical which can overcome contaminations occurring during introduction of explants to the in vitro environment. Actively growing shoot tips and nodal explants from 6 cm below from the shoot tip of C. fruticosa were selected as explants. Surface sterilization of these explants was carried out with silver nitrate in three concentrations, 0.025%, 0.05% and 0.1%. Clorox™ in 10% was used as the control. The explants were cultured in Murashige and Skoog (MS) medium, with 0.5mg/L benzyl amino purine (BAP), which was sterilized with CSUP media sterilization. Data of non-contaminated cultures was collected after three weeks and shoot growth from explants was recorded after two months. According to the results obtained the explants treated with 10% Clorox™, 0.025%, 0.05% and 0.01 % of AgNO3 had 13, 17, 22 and 40% uncontaminated cultures, respectively. These survived explants produced shoots in 50, 50, 60 and 66 % of uncontaminated explains, respectively after 2 months in the same medium. The production of uncontaminated cultures was significantly (P=0.001) different from the other two concentrations used and the control. The shoot production was not significantly affected by the AgNO3 levels and when compared with the control. Hence, it can be concluded that 0.1 % of Silver Nitrate is an efficient chemical to obtain high amount of axenic cultures and shoots, in CSUP sterilized medium, which can be used for multiplication in vitro.Publication Embargo Review on Methods of Explant Surface Sterilization for Efficient Micropropagation(Faculty of Humanities and Sciences - SLIIT, 2021-03-26) Hemathilake, H.M.; Peiris, S.E.Surface sterilization of plant parts which are introduced to commence in vitro establishment is a crucial activity in micropropagation. To begin the elimination of microbial contaminations, selected plant parts should come from healthy mother plants which are grown in a protected environment with minimal biotic and a biotic stress. However, other than epiphytic microorganisms, plants also harbour microorganisms in the intercellular spaces which are referred to as endophytes. Thus elimination of contaminants to obtain axenic cultures is a challenge especially since endophytes can be carried over to the multiplication stage. Bacteria, fungi and viruses are popular among in vitro culture contaminants; hence sterilizing agents which can destroy epiphytic as well as endophytic microorganisms should be used with different concentrations and exposure time according to the explant type and plant variety. In this respect, disinfectants such as Sodium Hypochlorite, Benzalkonium Chloride, antibiotics (tetracycline + vancomycin + streptomycin + gentamycin + rifampicin), fungicides (Daconil™, Benomyl,) are used in plant culture to control or destroy pathogens. Efficacy, handling and storage must be carried out in aseptic conditions. This article has filtered all the surface sterilization methods and obtained the easiest and effective methods of sterilization of commonly used explants such as leaves, buds, nodes and seeds.