Botany
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Item A comparative chemosystematical study of the genus Shorea in Sri Lanka(Proceedings of the sixth Round Table Conference on Dipterocarps, Bangalore, India, 1999) Perera N I S; Senanayake S PThe genus Shorea of the Dipterocarpaceae family is represented by 15 species in Sri Lanka, of which 13 are endemic. Because of the existence of different classification systems for this genus, proposed by several authors (Trimen 1974, Ashton 1980, Kostermann 1992), the aim of this study was to determine the taxonomic position of the genus Shorea using flavonoid composition. Flavonoid composition of the leaves of 11 species was studied using chromatographic techniques and UV visible spectroscopy. It was revealed that 48% flavonols, 36% flavones, 63% proanthocyanidins and 13% deoxy compounds were present in the leaves. In this study, a comparison of the flavonoid glycoside distribution patterns of Shorea stipularis and S. hulanidda suggested that the two species should be treated as different entities. However, several authors treat the taxonomic positions of these two species differently.Item A study of synergistic effects of some Sri Lankan essential oils against cowpea bruchids(Callosobruchusmaculatus,Proceedings of eleventh Asian symposium on Medicinal plants, Spices and Other Natural Products, Kunming, China, 2003) Paranagama, P.A.; Adhikari, A.A.C.K.; Abeywickrama, K.P.; Bandara, K.A.N.P.Item Address on “Why plant species become invasive? – Characters related to successful biological invasion”(Biodiversity Secretariat, 2014) Ratnayake, R.M.C.S.The impact of Invasive Plant Species (IPS) on biodiversity is irreversible and enormous because plant invasions can alter the functioning of an ecosystem dramatically. They also have a negative impact on environmental, economic and public wellbeing. Invasiveness of a species is dependent on any of five key factors: regional climate, microclimate, the site, past disturbance patterns, and individual species characteristics. The main focus of this paper is on species characteristics. Invasive species show high reproductive fecundity and great capability of spreading throughout their new location. Invasive species have characteristics that allow them to thrive in the area where they are introduced. However, how the characters of invasive alien species (IAS) determine their invasiveness is one of the key questions in invasion biology and this paper describes key characters of IPS, which are of great significance for their invasiveness. Compared to the native specialists‘ plants, the IPS are generalists, capable of surviving in a wide range of climatic conditions, which produce diverse habitats and soil variations. Therefore, IAS possess a broad habitat compatibility. In their new environment, IPS are not subjected to the damages of natural herbivores and diseases to maintain their maximum population densities, and hence they monopolize habitats. IPS enhances their invasive habit successfully by efficient competition for resource utilization and creating allelopathic effects to native biota. Invasive species also have high rates of growth and reproduction with early maturity. As a result, invasive species flourish in the settled landscapes as they produce many offspring and spread in to new area rapidly (high reproductive fecundity). Phenotypic plasticity and genetic differentiation are the two major strategies of IAS, which facilitate them to adapt to new habitats and environmental heterogeneity. Characteristics that make IPA successful in our environment are discussed with appropriate examples from IPS of Sri Lanka. However, generalizations can be misleading, because studies reveal different responses of native plants to the presence of IPS. Therefore, there is a need to understand general trends and exceptions within a particular habitat.Item Aflatoxigenic Aspergillus flavus and aflatoxin formation in selected spices during storage(2009) Rajasinghe, M.; Abeywickrama, K.P.; Jayasekera, R.Proliferation of aflatoxigenic fungi and accumulation of aflatoxins take place during storage of spices at various environmental conditions. The objective of this research was to identify the aflatoxigenic fungal species and their aflatoxin forming potential in selected spices during storage in the laboratory and refrigerator. Dilution series of spice samples namely chilli (Capsicum annum) powder, curry powder, turmeric (Curcurma longa) powder and pepper (Piper nigrum) powder (purchased from two producers) were prepared separately and the frequency of occurrence of aflatoxigenic and other fungi were assessed after plating each on Potato Dextrose Agar and incubating at ambient temperature. Aflatoxin formation of A. flavus was confirmed by growing a pure culture on a SMKY medium and identifying toxins on thin layer chromatographic plates. The presence of aflatoxins in spice samples stored at 30 ± 20C and 40C was also confirmed. Long storage of spices leads to aflatoxin production irrespective of storage temperature hence, it is advisable to consume spices such as chilli powerder, tumeric etc. within a relatively short period to avoid build up of aflatoxins.Item Air pollution monitoring at the Environmental Specimen Bank of Germany: spruce and pine shoots as bioindicators(Springer-Verlag, 1996) Rossbach, M.; Jayasekera, R.An investigation has been carried out to study the pattern of heavy metal abundance in buds, needles, twigs and cones from single trees and to compare the results with the integrated (composite, homogenized) ESB material of the same origin. It has been evident that (i) pine and spruce shoots are comparable in terms of the pattern of trace element abundance with the exception of Ni, Ba, Sr and Pb, (ii) twigs contribute substantially to the overall concentration of the homogeneous material, and (iii) heavy metal concentrations are remarkably different in samples from remote and industrialized sampling sites. To distinguish the influence of soil at different sampling sites on the overall concentration levels, an extensive investigation using chemometrical data evaluation has still to be carried out.Item An integrated strategy to control post-harvest decay of Embul banana by combining essential oils with modified atmosphere packaging(International Journal of Food science & Technology, 2007) Jayawardena, B.M.; Abeywickrama, K.P.Mature Embul (Musa, AAB) bananas were treated with emulsions of either cinnamon bark or leaf (Cinnamomum zeylanicum) or clove (Syzygium aromaticum) oils to control post-harvest diseases, packed under modified atmosphere (MA) using low-density polyethylene (0.075 mm, LDPE) bags, and stored in a cold room (14 � 1 �C, 90% RH) or at ambient temperature (28 � 2 �C). The effects of the essential oils on post-harvest diseases; physico-chemical properties and organoleptic properties were determined and compared with controls and bananas treated with benomyl. Treatments with cinnamon bark and leaf oils controlled crown rot, whereas clove oil treatment did not affect crown rot development. Treatment with emulsions of cinnamon oils combined with MA packaging can be recommended as a safe, cost-effective method for extending the storage life of Embul bananas up to 21 days in a cold room and 14 days at 28 � 2 �C without affecting the organoleptic and physico-chemical properties.Item Analysis of naphthalene and phenanthrene degradation catabolic genes of phyllosphere bacterial strains, Alcaligenes faecalis and Alcaligenes sp. DN25(2015) Kannangara, B.T.S.D.P.; Undugoda, L.J.S.; Sirisena, D.M.The bacterial strains, Alcaligenes feacalis and Alcaligenes sp. DN25 which were isolated from the phyllosphere of four ornamental plant species, Ixora chinensis, Ervatamia divaricata, Hibiscus rosa-sinensis and Amaranthus cruentus in five highly polluted sites in Sri Lanka, showed the highest phenanthrene and naphthalene degradation ability. Transformation and plasmid curing results of them revealed, naphthalene and phenanthrene degradation ability of these bacterial strains were plasmid encoded character. The occurrence of naphthalene specific (nahR and nahU) genes and phenanthrene specific (phnAc and phnG) genes of these catabolic plasmids were analyzed by PCR using degenerate primers. According to the amplification results, plasmids of Alcaligenes faecalis and Alcaligenes sp. DN25 harbour nahR, nahU and phnG genes but, lack of phnAc gene. RFLP and sequence data of nahU and nahR amplicons revealed, both of these genes were homologous to these two bacterial strains. But, phnG gene of two phenanthrene and naphthalene degrading phyllosphere bacterial strains was coexistence as two distinct copies of alleles.Item Annual fluctuations in populations of sea urchin Stomopneustes variolaris (Lamarck. 1816) in two rocky shores of southern Sri Lanka(Sri Lanka Association for Fisheries and Aquatic Resources, 2012) Thilakarathna, R.M.G.N.; Jayakody, S.; Amarasinghe, M.D.Sea urchins play a key role in rocky shore habitats as grazers. They form urchin fronts and extensively graze on macro algae resulting in regions of barrens and restructuring the habitat. The population status of Stomopneustes var/alaris (Lamarck, 1816) of Phylum: Echinodermata Class: Echinoidea, the most abundant sea urchin species in intertidal zones of Sri Lanka was investigated from June 2008 to May 2009. The study evaluated the density of S. varialaris and the influences of macro algae cover in two rocky shore areas from Hikkaduwa (legally protected) and Ahangama (legally unprotected) in Southern Province. Three habitats (near shore, intermediate and splash) were selected in each site. Line transect and quadrate (50X50cm) sampling methods were used to measure macroalgae cover whilst S. variolaris density of each habitat was measured using belt transect method (10m X O.5m) every month. Mean percentage occurrence of algae and density of S. variolaris were analyzed using multivariate techniques and general linear models. Accordingly, Canonical Variate Analysis of flora confirmed the distinctiveness of the three habitats in relation to floral cover mainly due to differences in the dispersion of Hypnea pannasa and Graciaria sp. sp. in Hikkaduwa and due to Padina sp., Ulva lactuca and Jania ungulata in Ahangama. Ninety nine percent of the variation was explained by axes 1 and 2 in both Hikkaduwa and Ahangama. Mean densities of S. variolaris recorded for Hikkaduwa and Ahangama were 1.65:t0.46 m.l and 0.71 :t 0.22 m'l respectively and Hikkaduwa had a higher density compared to Ahangama (p< 0.05). In Hikkaduwa the highest mean density (3.56 :t 1.48 m'l) was recorded in splash zone (p < 0.05), whilst in Ahangama the highest mean density (1.42:t 0.53 m'l) was recorded in near shore habitat (p< 0.05). A non significant peak density was observed in the months of April and July in Hikkaduwa, and October in Ahangama. Results indicated S. variolaris inhabiting in higher numbers towards the sea in Hikkaduwa but in Ahangama near to coast, perhaps a response to greater disturbance in Hikkaduwa due to visitors.Item Antifungal activity of Croton aromatics L. in vitro, against post-harvest fungal pathogens isolated from tropical fruits(Faculty of Agricultural Sciences, Sabaragamuwa University of Sri Lanka, 2016) Wijesundara, S.A.D.T.L.; Kannangara, B.T.D.S.P.; Abeywickrama, K.Item Antifungal effect of Croton aromaticus against Rhizopus spp. Isolated from banana and papaya(Institute of Biology, Sri Lanka, 2015) Wijesundara, S.A.G.T.L.; Kannangara, B.T.S.D.P.Item Aromatic hydrocarbon degrading Phyllosphere Fungi(University of Sri Jayawardhanapura, 2013) Undugoda, L.J.S.; Kannangara, S.; Sirisena, D.M.Item Assessment of epiphytic lichen diversity in pine plantations and in adjacent secondary forest in Peacock Hill, Pussellawa, Sri Lanka(2015) de Silva, C.M.S.M.; Senanayake, S.P.Item Background levels of heavy metals in plants of different taxonomic groups from a montane rain forest in Sri Lanka(Kluwer Academic Publishers, 1996) Jayasekera, R.; Rossbach, M.An undisturbed natural reserve area iocated in a tropical montane rain forest at about 1800 m altitude in Sri Lanka served as a study site to investigate and assess the natural background concentration levels of As, Cd, Co, Cu, Ni, Pb and Zn in plants representing different taxonomic groups (divisions) in the plant kingdom. The plants selected were: the lichen,Usnea barbata (old man's beard);Pogonatum sp. (a moss);Lycopodium selago (epiphytic lycopod);Polypodium lanceolatum (epiphytic fern);Bulbophyllum elliae (epiphytic orchid) andActinodaphne ambigua(dicotyledonous large tree). Degree of homogeneity with respect to Cd, Cu, Pb and Zn in homogenised materials of all samples were within acceptable limits, whereasPogonatum sp. showed the highest degree of homogeneity for Pb. In addition to confirming extremely low levels of heavy metals in all plant species, the survey also found that generally the primitive plants,UsneaandPogonatum appear to have a greater tendency to accumulate As, Cd, Co and Pb; in particular,U. barbata appears to be an efficient accumulator for those heavy metals, suggesting its potential use in environmental studies.Actinodaphne ambigua was found to have a specific accumulating ability for nickel. Surface cleaning of theA. ambigua leaves resulted in a substantial decrease in the foliar contents of Cd, Ni, Pb and Zn. Variations in heavy metal contents observed in different plant genera are discussed in terms of their habits and place of growth in the forest. It is anticipated that the background levels presented in this paper from a remote, unpolluted tropical ecosystem will provide useful reference data for comparative environmental studies.Item Basil oil plus aluminium sulfate and modified atmosphere packagingcontrols Crown rot disease in Embul banana (Musa acuminata, AAB) during cold storage(Elsevier, 2017) Siriwardanaa, H.; Abeywickrama, K.; Kannangaraa, S.; Jayawardena, B.; Attanayake, S.tEffect of basil oil spray treatment in combination with modified atmosphere packaging was investigatedin controlling crown rot and extending the shelf life of Embul banana (Musa acuminata, AAB) at 12–14◦C.Embul banana fruits were treated with 1% aluminium sulfate, 1% aluminium sulfate + 0.4% basil oil and dis-tilled water (control). Treated banana samples were packed in Low Density Polyethylene bags and storedat 12–14◦C. In-package gases were analysed after 14 days of cold storage. Physicochemical properties,nutritional properties, sensory properties and crown rot disease severity as well as residues in treatedbanana peel were determined in ripening induced fruits. Test marketing trials were conducted in fruit out-lets in Dambulla and Kiribathgoda, Sri Lanka where treatments were provided to consumers and staff toobtain feedback on the quality of treated banana. At the end of 14 days, O2in packages remained between3.1–3.7% while CO2varied from 4.2 to 4.7%. 1% aluminium sulfate + oil treatment significantly controlledcrown rot disease compared to others. Most of the physicochemical, sensory properties of aluminiumsulfate + basil oil treated banana were not significantly different compared to control whereas nutritionalproperties of treated samples showed no drastic changes compared to control. Treated samples scoredhigher for peel colour and taste over control samples, by staff and consumers of fruit outlets. Consumerspreferred basil oil treated banana over untreated due to their sweet and pleasant taste. Insignificantamount of residues persisted in treated banana. This current safe, eco-friendly treatment strategy couldbe recommended in preparing Embul as well as other banana varieties belonging to Musa acuminata, AABgroup for commercial scale export to various destinations which require a transit time of two weeks.Item Behavioural Studies of Cowpea Seed Bruchid, Callosobruchus maculatus (F.) Against Volatile Leaf Extracts of Lemongrass, Neem and Curry Leaf(Tropical Agricultural Research, 2002) Adhikari, A.A.C.K.; Paranagama, P.A.; Abeywickrama, K.P.; Bandara, K.A.N.P.Item Bioactivity of leaf volatiles of Azadirachta indica A. and Murraya koenigii (spreng) against Sitophilus orysae (L.) (Coleoptera: Curculionidae)(Tropical Agricultural Research and Extension, 2002) Paranagama, P.A.; Abeysekera, K.H.T.; Nugeliyadde, L.; Abeywickrama, K.P.Item Bioactivity of the essential oil of Cymbopogon citratus (Lemongrass) on Sitophllus oryzae(L) (Coleoptera : Curcuolionidae) [Rice Weewil](Sri Lanka Association for the Advancement of Science (SLAAS), 2001) Paranagama, P.A.; Jayaratne, K.H.T.; Nugeliyadde, L.; Abeywickrama, K.P.Item Bioactivity of the essential oil of lemongrass, (Cymbopogon citratus) against rice weevil-Sitophilus oryzae(L.) and grain moth-Sitorroga cerealella (Olivier)(Annual Research Symposium, Faculty of Graduate Studies, University of Kelaniya, 2001) Jayaratne, K.H.T.; Paranagama, P.A.; Nugeliyadde, L.; Abeywickrama, K.P.Item Bioactivity of volatile constitutents of Sri Lankan plants against cowpea bruchids, Callosobruchus maculatus(Proceedings of AFASSA Regional Symposium on Natural Products, 2004) Paranagama, P.A.; Abeywickrama, K.P.; Bandara, K.A.N.P.; Adhikari, A.A.C.K.Item Bioconcentraton of metals in edible aquatic plants from a Sri Lankan freshwater wetland(Sri Lanka Association for Fisheries and Aquatic Resources, 2008) Amarasinghe, M.D.; Nirbadha, K.G.S.; Liyanage, J.A.