Browsing by Author "Rajapakse, R.G.S.C."

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Development of suitable propagation systems for Tephrosia spp. and Flueggea leucopyrus in Sri Lanka
(University of Kelaniya, 2013) Priyadarshan, A.I.S.; Senanayake, S.P.; Jayetilleke, M.P.; Rajapakse, R.G.S.C.
Different species of both genera Tephrosia and Flueggea are commonly used as ingredients in traditional therapeutic preparations. Due to the increasing popularity of these plants as ingredients in traditional therapeutic systems, production of planting materials for commercial cultivation is a timely requirement. This research was carried out to develop suitable propagation systems for T. purpurea, T. villosa, T. noctiflora, T. pumila and F. leucopyrus. Though Tephrosia spp. seeds have shown higher viability, low germination percentage was observed within a week on wet filter paper as well as in different six potting media. Six potting media were prepared using five raw materials namely coir dust, sand, top soil, cow dung and compost with different compositions to evaluate the seed germination and growth performance of Tephrosia species. Water impermeability of seed coats was identified as the reason for the seed dormancy in Tephroisa spp. and soaking in Con. H2SO4: H2O; 3:1 for 25 mins and rubbing on sandpaper for 2 mins were determined as suitable seed dormancy breaking methods. Variation was observed in the growth performance of Tephrosia spp. in six different potting media. Soil medium was determined as a more suitable medium compared to the hydroponic solution for all four Tephrosia species. Due to less seed production in F. leucopyrus, stem cutting propagation methods in three different potting media (Coir dust, Sand, Coir dust: Sand 1:1) were applied to evaluate the efficiency in propagation. Semi hardwood and hardwood cuttings of F. leucopyrus were well established within a period of a week in sand potting medium. These findings can be used to establish suitable propagation systems for genera Tephrosia and F. leucopyrus for commercial cultivation.
Efficiency of Biofilm Biofertilizer in Increasing Plant Growth Parameters of Rice Cultivation In Sri Lanka
(International Postgraduate Research Conference 2019, Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2019) Meepegamage, S.W.; Seneviratne, G.; Rajapakse, R.G.S.C.
Agricultural land per unit area needed to obtain the highest productivity and quality products, in order to win the challenging need for food products to feed a growing world population. For that, excessive chemical fertilizers (CF) are used for a long period of time for the agricultural lands which affect adversely on soil health and plant production. Application of CFs on cultivated lands suppresses the soil microbial activities and leading to develop poor microbial communities with law biomass. Microbial biofertilizers, a viable substitute for CFs are reported to increase diversity and abundance of soil microbes by introducing beneficial microbes which are depleted in agroecosystems. They consist of live beneficial microbes such as fungi, bacteria and algae which may include single or multiple combinations to enhance microbial activities. Among biofertilizers, more efficient biofilm biofertilizers (BFBF) which consist of developed microbial communities and extra polymeric substances play a crucial role in plant growth and soil processes. BFBFs are observed to produce various plant hormones, hydrogen cyanide and siderophore like exudates and amelioration of plants from stress. Moreover, they are involved in activities like nitrogenase activity, antagonistic activity defense against plant pathogens and solubilization and mineralization of soil nutrients such as phosphorus. BFBFs which ensure the sustainability of agroecosystem help for plant growth and development. Thus, the present study focused on the effect of BFBF on plant growth parameters under CF reduction in the conventional agriculture using rice as the test plant. A rice field experiment was conducted with four treatments viz: 100% CF DOA recommendation (DCF, 136 kg NPK per acre), NIFS CF recommendation for BFBF practice (NCF, 90 kg NPK per acre), NIFS CF recommendation for BFBF practice + BFBF (NCF + BFBF, 1000 ml BFBF per acre), and the control (without CF and BFBF), each having three replicates. Plant samples were collected randomly from all four treatments and leaf chlorophyll content was measured in the field using SPAD-502-Chlorophyll meter. Furthermore, total dry weight per hill, total number of tillers per hill, circumference of plant shoot, thousand seed weight and chaff content were measured. The data were analyzed using Minitab statistical package. There were significant increases in total dry weight of the plant (increase by, with respect to DCF: 89%, NCF: 98%, control: 98%), total number of tillers per hill (with respect to DCF: 93%, NCF: 73%, control: 86%) and circumference of the plant shoot (with respect to DCF: 52%, NCF: 35%, control: 40%) (p < 0.05) in the NCF + BFBF treatment over the other three treatments. NCF + BFBF showed the higher leaf chlorophyll content (with respect to DCF: 6%, NCF: 1%, control: 33%), thousand seed weight (with respect to DCF: 3%, NCF: 1%, control: 9%) and the lower chaff content (decrease by, with respect to DCF: 33%, NCF: 8%, control: 33%) than those of other three treatments. The study concludes that the BFBF application together with a reduced dosage of CFs improves the plant growth and grain yield in conventional rice cultivation
Phenetic variation and phenolic composition of leaves of Flueggea leucopyrus willd. (vern: Katupila) collected from different climatic zones in Sri Lanka
(University of Kelaniya, 2013) Priyadarshan, A.I.S.; Senanayake, S.P.; Jayetilleke, M.P.; Rajapakse, R.G.S.C.
Flueggea is a genus of thorny shrubs belonging to the family Euphorbiaceae, and represented by two species in Sri Lanka. Currently, Flueggea leucopyrus is becoming increasingly popular as an ingredient in several traditional therapeutic systems in Sri Lanka, as well as in other countries. According to a questionnaire survey, carried out using a population sample of hundred, the distribution of F. leucopyrus was found to be common in the dry zone, compared to the wet zone of Sri Lanka. Most of the users are of the opinion that the best ingredients for traditional therapeutic systems can be obtained from plants grown in the dry zone. Therefore, the aim of this study is to interpret the phenetic variation and determine the phenolic composition in leaf extracts and of F. leucopyrus in different climatic zones in Sri Lanka. Floral and vegetative characters of F. leucopyrus in fifteen localities in districts of Colombo, Kurunagala, Puttalam and Hambanthota were observed and cluster analysis was done. Leaf material collected from fifteen different localities were acid hydrolysed and extracted into ethyl acetate and ether. Ethyl acetate extracts were used to isolate flavonoid aglycones using cellulose Thin Layer Chromatography (TLC) plates in solvent 50% acetic acid. Ether extracts were used to isolate phenolic compounds using 2-Dimensional paper chromatography in solvent systems, butanol: acetic acid: water; 6:7:3 and sodium formate: formic acid: water; 10:1:200. Then colors of the spots were observed under UV (366nm) and Rf values were calculated. Then cluster analysis was carried out to determine the distribution pattern of flavoniod aglycones and phenolic compounds. Slight phenetic variation was observed among the different population samples. Intra specific variation can be seen in the distribution of phenolics and flavonoid aglycones in leaves of F. leucopyrus with respect to their habitats in different climatic zones. The variation observed in the specimens of different localities in the dry zone is higher than the wet zone samples. To determine the variation in the efficacy of leaves of F. leucopyrus in preparation of therapeutic systems, further elucidation of phytochemicals is needed.