Research Publications Authored by SLIIT Staff

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This collection includes all SLIIT staff publications presented at external conferences and published in external journals. The materials are organized by faculty to facilitate easy retrieval.

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Author: search.filters.author.Peiris, SEnd date: 2009

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Now showing 1 - 10 of 15
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    PublicationOpen Access
    Establishment of embryogenic cell suspension culture of chilli (capsicum annum L. var. accuminatum fingerh) for somatic embryogenesis
    (Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 1996) Nandakumar, J; Bandara, J. M. R. S; Peiris, S
    Chilli [Capsicum annum L. var. accuminatum Fingerh] is one of the important spice crops ofSri Lanka. Embryogenic suspension cultures of chilli were developed with an objective to induce somatic embryogenesis Successful callus induction was obtained from both leaves and cotyledons of two weeks old seedlings in MS medium containing 1 ppm 2, 4 • D, after incubation in the dark for two to three weeks. A combination ofKinetin (0.x ppm) and 2,4- D (1 ppm) promoted callus proliferation at a high rate. Cell suspension cultures were established using 2 g of four week old leaf and cotyledon calli in 20 ml of liquid MS medium with 1 ppm 2, 4- D in 100 ml Erlenmeyer flasks. Weekly sub culturing was performed. MS medium with 2. 4-D (1 ppm) stimulated embryogenesis on cotyledon callus after 12 weeks in culture. Embryogenic calli formed are pale yellow to brown, compact, organized and nodular in appearance. It comprised of small, richly cytoplasmic cells without large vacuoles. Both initiation of embryogenic cells and the subsequent development of these cells into embryoids occurred in the. same MS (2, 4-D 1 ppm) medium. Within a period of five to seven days, 12 week old, 20 ml of embryogenic cell suspension produced 14 proembryoids After 7-14 days they developed into heart stage and to mature embryoids Plantlet development has not observed until now in the tested MS media, containing activated charcoal, zeatin, IBA and GA3.
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    PublicationOpen Access
    An evaluation of genetic diversity in micropropagated anthurium using starch gel electrophoresis
    (Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 1992) Peiris, S; Mantell, S. H; Peiris, C. N; Senanayake, Y. D. A
    Anthurium andreanum Lind is a cut flower which is in high demand in the local and export cut flower trades in Sri Lanka. For commercial production of export anthurium cut flowers, it is essential that the selected elite qualities of the flowers borne on this original mother stock plants are maintained consistantly through many generations on vegetative multiplication. Tliis paper reports on stanch gel electrophoresis which was adapted successfully on anthuriums to evaluate genetic diversity if any, in plants derived either from seedlings, conventional stem cuttings or micropropagated clonal plants. Buffered leaf extracts were compared by means of horizontal starch gel electrophoresis to check the variability in cv. 'Crinkled Red'. Isoenzyme banding patterns of malic dehydrogenase (MDH), 6 phosphogluconic dehydrogenase (6 PGDH), phosphogluco isomerase (PGI) and diaphorase (DIAP) were used. Extracts of 105 seedlings, 60 clonal plants produced through rhizome cuttings and 150 in vitro propagated plants were compared to detect possible somaclonal variations in the daughter plants produced. Results of starch gel electrophoresis showed that extracts of seedling plants contained variations, expressed as percentages showing deviant patterns in all five isoenzyme systems assessed: MDH 14%, 6 PGDH 13%, GOT 12%, PGI 14% and DIAP 16%. None of the clonal plants or in vitro propagated plants tested using this technique showed variations in any of the isoenzyme compared. Tlie results of this study showed the genetic diversity in anthwium seedling plants and confirmed that stability was maintained in vegetatively propagated and in vitro propagated plants. Since in vitro propagation produces a large number of uniform and genetically stable plants, in vitro multiplication would appear to be suitable for use in the Sri Lankan floriculture industry
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    PublicationOpen Access
    Biodiversity of fruit and other tree species in the Huruluwewa watershed with emphasis on their economic utility
    (Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 1997) Amarasinghe, A. A. Y; Peiris, B. C. N; Peiris, S
    This stud}1 attempted to determine species and genetic diversity in the Huruluwewa wa'ershed considering basic information on native tree species with emphasis oi i fruit and other tree species of future economic utility. This study :vas carried out in different phases, namely, "reconnaissance survey" leading to specific information of the Huruluwewa watershed to determine the species diversity and "Identification of genetic diversity of fruit tree species" through starch gel electrophoresis techniques. Few groups of fruit tree species showing close similarities were used to establish the "Finger printing" through starch gel electrophoresis to identify the genetic diversity. The existing high degree of species diversity in the Huruluwewa watershed can be categorized into different groups based on their economic utility. These are fruit ti ee species, medicinal plants, firewood species, timber trees, ornamental plants food crops, shade trees, cover crops andfodder crops. Different banding patterns in the starch gel electrophoresis established for fruit tree species with closn morphological similarities, indicated the genetic diversity within and among fruit tree species in the watershed
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    PublicationOpen Access
    Preservation of Plumeria rubra L.(Rathu Araliya) for dry flower arrangements
    (Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 2007) Karunananda, D. P; Peiris, S
    This study was carried out to optimize a flower drying technique applicable for long term preservation of Plumeria rubra L. in dry flower arrangements. Silica gel, borax with corn meal, river sand, sea sand and air drying were used to dry the P. rubra flowers. Retention of colour and shape of dried flowers were evaluated comparing against Royal Horticultural Colour Chart and designating weighted scores for each colour. Reduction of flower weight was used to select the methods for rapid drying. Preservation using silica gel and river sand showed significantly performances in colour retention at the completion of drying at four days. Silica gel, river sand, borax with corn meal and sea sand showed significantly different performances (p= 0.05) in shape retention when compared with the control. P. rubra petiole fixed well to metal wires showing ability of use for dry flower arrangements.
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    PublicationEmbargo
    Control of circadian rhythm-regulated nyctinastic movement in water lily (Nymphea stellataWilld.) flowers
    (Taylor & Francis Group, 2005-01-01) Samarakoon, U. C; Peiris, S
    Flowers of Nymphea stellata Willd., like other water lilies, are subject to circadian clock-controlled petal closure in the afternoon. To investigate the effects of plant growth regulators, and various other chemicals, in arresting nyctinastic movement (petal closure), cut flowers of N. stellata were exposed to different concentrations of gibberellic acid (GA), benzyl amino purine (BAP), naphthalene acetic acid (NAA), abscisic acid (ABA), ethanol, AgNO3, NaCl or Rinso (laundry detergent powder). The most effective treatment to control the biological clock of petal movement was keeping flowers continuously in 25 mg l–1 GA. This treatment kept flowers open, to an acceptable cut flower standard, for over 28 h. Continuous exposure to 5 mg l–1 BAP also kept flowers open to the same acceptable standard for over 15 h. Considering low-cost applications, immersing flowers in 25 g l–1 NaCl for 1 h kept them open for almost 17 h, to an acceptable cut flower standard. Immersing in 2 g l–1 Rinso (Unilever, Sri Lanka) for 1 h also kept flowers open for 14 h in an acceptable condition. By inhibiting nyctinastic closure using any of the above chemicals, N. stellata could now be considered and exploited as a cut flower.
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    PublicationOpen Access
    Effects of selected post harvest treatments on vase life of cut flower gladiolus (Gladiolus grandiflorus)
    (Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 2000) Premawardena, P. S; Peiris, B. C. N; Peiris, S
    A postharvest storage study with different treatments was carried out to investigate a procedure in prolonging the vase life of cut-flower gladiolus. Various chemical and non chemical treatments which are locally available were used. In comparison with the control (distilled water), beverages such as 7-UP™ in different concentrations, specific anti-ethylene compounds, silver nitrate and silver thiosulphate (STS), benzyl amino purine (BAP) in different concentrations, hot water treatment to the base ofthe flower stalk as a sterilizing method, maintaining the pH at 3.5 using HCI, eylene oxidization with KMn04 and ethylene absorption with activated charcoal were tested The longest vase-life and the best visual quality were achieved by gladiolus flowers treated with 25% 7-UP™. Next best visual quality were achieved by Silver nitrate, 2.25% 7-UP™, 4 mg t' KMn04 and STS in the descending order. Flowers treated with 2 mg t' KMn04 and the control (distilled water) had the lowest vase life. The visual quality was lowest in flowers treated with 2 mg t1 KMnO^ When the cots ofcompounds used were considered the study indicates that the treatment 7-UP™ and KMn04 were found to be the cheapest, while silver nitrate and silver thiosulphate are comparatively expensive.
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    PublicationOpen Access
    Transient expression of uida reporter gene in regenerable callus tissues of Anthurium andraeanum lind. by agrobacterium mediated transformation
    (Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 2000) Yakandawala, G; Peiris, S; Yakandawala, Y. L. N
    A tissue culture scheme for plant regeneration via callus, and a protocol for gene transfer to regenerable callus are described for Anthurium andraeanum variety A vo Nette. Callus was induced from shoot bases and from leaf blades of Anthurium andraeanum on modified MS media containing 0.3 mg t' 2,4-D and 0.5 mg t' BAP. Shoot bases, leaf blades with a single cut at the base, and sectioned leaf blades produced callus at frequencies of 90%, 20% and 8%, respectively. Plant regeneration was obtained at a high frequency in all callus types, irrespective of their origin, in modified MS media containing 0.5 mg t' BAP. Callus was tested for gene transfer efficiency by 2 Agrobacterium tumefaciens strains, C58 andLB4404, carrying binary vector p CAMBIAi } oi containing hpt and uidA reporter genes under plant expression signals. Transient expression of uidA gene monitored by GUS histochemical assay was observed only in callus inoculated with Agrobacterium strain LB4404 at a frequency of 3.33%.
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    PublicationOpen Access
    Preliminary investigation of preservation methods to produce dried flowers of rose and statice
    (Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 2000) Kumari, D. L. C; Peiris, S
    An experiment was carried out to investigate methods which preserve rose and statice to retain its high quality standards as dried flowers. Air-drying, glycol preservation and use of desiccants were applied as preserving methods. Colour of petals, dryness of petals and overall appearance of the flower at the end of the drying process were evaluated as quality standards. The highest quality standard in rose was shown within 2 weeks by the preservation method using silica gel as a desiccant. Air drying showed better results than glycol when preserving rose. In statice, air drying was the best method which retained quality standards. The highest score was obtained in the 4'h week Statice exposed to glycol preservation did not show high quality standards. This experiment revealed the best preservation methods for rose and statice are silica gel desiccant and air drying respectively
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    PublicationOpen Access
    Potential low cost treatments for extending the vase life of anthurium (Anthurium andreanum lind) flowers
    (Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 2000) Yapa, S. S; Peiris, B. C. N; Peiris, S
    Flowers, being viable and actively metabolizing parts of plants, are subject to ageing processes and thus are perishable commodities. In order to meet the requirement for export market of cut-flowers it is necessary to prolong the vase-life while maintaining quality. Specific anti- ethylene compounds, which are expensive, are presently being used to break the ageing process. An investigation was therefore carried out to extend the vaselife of cut-flower Anthurium gndregnum. using inexpensive treatments in comparison with conventional methods. The flowers were treated with different concentrations of antiethylene compounds, such as AgNO, silver thiosulfate (STS), benzyl amino purine (BAP), KMn04 , glycerine and hot water. Distilled water treatment was used as the control. The longest vase-life lasting 14 days was obtained with 2 mg t' KMnO+ This was followed by STS (12.87days), 10 mg t' BAP (12.43 days), 5 mg t1 BAP( 12.37 days) and 1000 mg t' AgN03 (12.25 days). Hot water and 15 mg t' BAP did not significantly affect the vase-life. Flowers treated with different glycerine concentrations showed the lowest- vase-life compared to the control. The cost analysis revealed that the KMn04 treatment is the cheapest method. Moreover, amongst conventional treatments, AgNO3, BAP and STS at tested concentrations were not found to be cost effective.
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    PublicationOpen Access
    Modification of plant architecture of Hemidesmus indicus (L.) R. Br.(Iramusu) by in vitro colchicine treatment
    (Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 2008) Nagahatenna, D. S. K; Peiris, S
    he effects of different concentrations of colchicine on shoot and root development of nodal explants and germinating somatic embryos of Hemidesmus indicus (L.) R. Br.(Iramusu) was investigated. MS medium solidified with 8 g/l agar was superior to the liquid medium in all the concentrations of colchicine. In nodal derived H. indicus plants, the highest number of shoots per explant (4.23±1.49) and the longest shoot length (6.36±4.29 cm) were achieved at 5 mg/l colchicines forming a compact bushy type plant architecture. In almost all the treatments an increment of shoot length and number of shoots per explant could be observed compared to the control plants. Furthermore, 1 mg/l colchicine was more effective in germinating somatic embryos to produce more compact plant type under in vitro condition. There was no significant difference observed in different concentrations of colchicine on root length and root …