Browsing by Author "Krishnarajah, S.A."

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    Development of In-vitro and Conventional Propagation Protocols for Two Different Endemic Species of Aponogeton (Aponogeton rigidifolius and Aponogeton jacobsenii)
    (Uva Wellassa University of Sri Lanka, 2016) Weerasekara, W.N.V.; Bambaranda, B.V.A.S.M.; Jayamanne, S.C.; Krishnarajah, S.A.
    This research was focused on the development of successful propagation protocols for two different endangered and threaten aquatic plant species of A. rigidifolius and A. jacobsenii. Due to lack of effective propagation methods, Aponogeton species indiscriminately harvested from wild and leads to extinct. To overcome the problem of species loss and inadequate supply to the local and foreign market, in vitro and conventional propagation protocols were developed for both species. Rhizomes, seeds and leaf explants of both species were sterilized using NaOCI and 0.1 % HgC12 and established on full strength MS medium supplemented with combination of 6- benzylaminopurine (BAP) 2, 3, 5 mg/L with or without 0.1 mg/L indole acetic acid (IAA) for initiation. For shoot multiplication 2, 3, 5 mg/L BAP were used. Rhizome cuttings and seeds of both species were planted in pots, which contain sand, sand: top soil, top soil and boggy soil with water as conventional propagation method. Experiment was arranged in Complete Randomized Design method and data were analyzed using ANOVA and Tukey's Test. The presence of growth regulators had significant effect (p<0.05) on shoot initiation of A. rigidifolus rhizome. The highest shoots per replicate (2.4) were proliferated in 2 mg/L BAP medium. Application of hormones had a significant effect on number of leaves and seedling height of seed explants of both species. Maximum number of leaves (5) and seedling height (5.8cm) in A.rigidifolius obtained from the treatment which supplemented both 5 mg 1-' BAP and 0.1 mg IAA while the highest leaves (3.43) and height (1.92 cm) shown in 5 BAP alone medium in A. jacobsenii seedlings. The highest shoots per seedling (4.2) obtained from 2 mg BAP contain multiplication medium in A. rigidifolius seedling. Conventional growth media significantly influence on the shoot development from A. rigic4folius rhizome cuttings, seed germination, and in other seedling growth parameters of both species. Mean number of leaves, height of seedlings, and number of roots and length of roots were high in both plants which planted in boggy soil medium. The highest shoots ofA. rigidifolius obtained in sand medium. Keywords: Aponogeton rigidifolius, Aponogeton jacobsenii, in-vitro
  • No Thumbnail Available
    Item
    Development of Micro-Propagation Protocol for Aponogeton dassanayakei
    (Uva Wellassa University of Sri Lanka, 2018) Hettiarachchi, H.D.B.K.; Coswatte, A.C.W.W.M.C.L.K.; Senaratne, M.M.D.J.; Krishnarajah, S.A.; Kaliyadasa, P.E.
    Aponogeton is a genus of freshwater aquatic plants and there are five Aponogeton species native to Sri Lanka with three endemic members. They have a high demand as an ornamental aquarium plant, food source and medicinal herb. Due to these reasons over exploitation of plants from natural habitats is common with poor attention on conservation. Aponogeton dassanayakei is a newly identified Aponogeton species from Sri Lanka. This study was carried out to develop a micropropagation protocol for newly identified Aponogeton dassanayakei. Treatments included full strength Murashige and Skoog (MS) solid basal media supplemented with combinations of 6-benzylaminopurine (BAP) (0.00, 1.00, 2.00 mg L-1) with 0.10 mg L-1 Indole-3-acetic acid (IAA) and without IAA for both shoot initiation and multiplication in seed culture. Ten replicates obtained per each treatment. During shoot initiation seed germination rate, seedling height and number of leaves per seedling were taken as the response variables and shoot multiplication stage plant height and number of leaves were considered. Application of hormones showed significant effect (p < 0.05) on both number of leaves and seedling height but not on seed germination rate in shoot initiation. Hormones supplemented in solid media during shoot multiplication were shown significance difference (p < 0.05) in plant height but not in number of leaves. According to the study, MS medium supplemented 1.00 mg L-1 BAP is the best for shoot initiation. MS medium containing 2.00 mg L-1 BAP is best for shoot multiplication. The study demonstrated that micro-propagation could be useful for large scale propagation of Aponogeton dassanayakei while conserving the plant in natural habitat.
  • No Thumbnail Available
    Item
    Perfecting Explants Sterilization Procedure and Multiple Shoot Induction Medium for In-Vitro Propagation of Lagenandra Species
    (Uva Wellassa University of Sri Lanka, 2013) Premathilake, P.G.A.D.; Bambaranda, M.; Jayamanne, S.C.; Krishnarajah, S.A.
    Lagenandra species are important aquatic plants in the aquaculture industry of Sri Lanka (Yapabandara and Ranasinghe, 2006). In the absence of a regular supply due to lack of effective propagation methods, Lagenandra species are indiscriminately harvested from the wild to supply to the export market. In order to overcome the problem of species loss and inadequate supply to the local and foreign markets, an in vitro micro- propagation method was developed for Lagenandra lancifolia and Lagenandra ovata. The maintenance of aseptic or sterile conditions is essential for successful tissue culture procedures. Various sterilization agents are used for surface sterilization the tissues. These disinfectants are also toxic to the plant tissues, hence proper concentration of disinfectants, duration of exposing the explants to the various disinfectants, the sequences of using these disinfectants has to be standardized to minimize explants injury and achieve better survival (CPRI, 1992). Mercuric chloride and sodium hypochlorite were used for the present study to standardize the best sterilization protocol for in vitro culture of Lagenandra ovata and Lagenandra lancifolia. Culture initiation and multiplication, to a great extent, are dependent on the type and genotype of explants as well as the type of hormone and their concentration. Many commercial ornamental plants are being propagated by in-vitro culture on the culture medium containing auxins and cytokinins (Peril, 2003).BAP (6- Benzylaminopurine) and IAA (Indole acetic acid) hormone with different concentration were used in the present study to perfect the best combination of IAA and BAP in shoot multiplication procedure. Methodology The research was conducted at the tissue culture laboratory, Floriculture research and development unit, Royal botanic gardens, Peradeniya. The rhizomes (1 cm - 2 cm pieces) were used as explants. In the first experiment, explants were soaked in different concentrations of sodium hypochlorite (15%, 20%, and 25%) and mercuric chloride (0.1%, 0.2%, and 0.4%) to perfecting explants sterilization procedure. Each explant was soaked for twenty minutes in Sodium hypochlorite solution and two minutes in Mercuric chloride solutions. Number of contaminated cultures was observed after two weeks from explants establishment in hormone free Murashige and Skoog medium. In second experiment, effect of different hormone combinations (hormone free MS medium, , BAP 7 mgl +IAA 0.1 mgl ) in 0.5 MS semi solid medium, full MS semi solid medium and full MS liquid medium for shoot initiation and multiplication were evaluated. Number of shoot initiation, shoot length, number of shoots per culture and number of leaves per culture were recorded after six weeks from explants establishment in MS medium.All the data were analyzed using ANOVA in SAS and Minitab statistical package.