Browsing by Author "Madushani, K.P.K."

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Effect of Biofilm Biofertilizer and Chemical Fertilizer Application Practices on Growth and Endophytic Bacterial Count of Rice (Oryza sativa L.)
(International Postgraduate Research Conference 2019, Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2019) Lakmini, A.L.A.; Seneviratne, G.; Madushani, K.P.K.
Utilization of beneficial microbes as a biofertilizer has become paramount importance in the agriculture sector for their potential role in sustainable crop production. Nitrogen-fixing bacteria with rhizosphere fungi form fungal-bacterial biofilms which can be developed as biofilm biofertilizers (BFBFs) as an extension of biofertilizer research application which could save chemical fertilizer use (CF) for many crops with a wide range of beneficial biological functions. BFBF application has been reported by many authors to significantly increased rice yield with lower CF inputs, as it facilitates biological nitrogen fixation with non-legumes (rice, tea, wheat, and vegetables), while increasing solubility and availability of phosphorous and other macro, micro nutrients as a result of its beneficial interactions between bacteria and fungi as well as interaction between soil and microorganisms. This study investigates the effect of commercially available biofilm biofertilizer and chemical fertilizer application practices on growth and endophytic bacterial count of rice after the 2013 new chemical fertilizer recommendation by the Department of Agriculture Sri Lanka. This experiment was conducted in two selected fields at Dehiaththakandiya in Mahaweli system C and Rice Research and Development Institute, Bathalegoda. Six different treatments were applied (100% CF, 80% CF, 80% CF + BF, 65% CF, 65% CF + BF and no fertilizer as the control). The experiment was arranged in Randomized Complete Block Design with four replicates to each treatment. Plant growth (root and shoot length, tiller and panicle count, total dry mass) and soil parameters (soil pH, available ammonium, nitrate and phosphate levels) were recorded at both tillering and flowering stages. Endophytic bacteria were isolated from rice leaves and root samples to obtain a colony count. Data were subjected to statistical analysis. Results indicate that BFBFs influenced positively on plant-microbe interactions. BFBF significantly increased both vegetative and reproductive parameters of rice plants with increasing trend of total and diastrophic endophytic bacterial count compared to CF. Therefore, the application of BFBFs to the soil could induce endophytic diversity and their functionality. This indicates that the effects of community based approach of microbial biofilms increases soil and plant well-being for ensuring higher yield with the sustainability of the rice agro-ecosystems to restore their depletion due to chemical agriculture
In-vitro and in-vivo Seed Germination Percentage of Typha angustifolia
(International Postgraduate Research Conference 2019, Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2019) Madushani, K.P.K.; Amarasinghe, M.D.; Ratnayake, R.M.C.S.; Dahanayaka, D.D.G.L.
Typha is a cosmopolitan genus and T. angustifolia is considered an alien invasive plant species in Sri Lanka. Extensive distribution of T.angustifolia is observed in Bundala wetland complex during the recent past. Seed germination is an important process that contributes to plant distribution and invasiveness. Therefore, this study aimed to investigate the in-vitro and in-vivo seed germination of T.angustifolia seeds to evaluate the percentatge seed germination of Typha seeds. Typha seeds were collected from Bundala wetland complex, Hambantota, Sri Lanka (6°12′50″N; 81°13′30″E) during the South West monsoon windy season (seed dispersing period). Typha seeds were cleaned with distilled water and settled in distilled water to select the most viable seeds, which sink to the bottom of the container, whereas non-viable seeds float. Seed viability was tested by placing 50 seeds on cavity slides with 3% 2,3,5-triphenyltetrazolium chloride (TTC) solution and percentage seed viability was calculated after incubating in dark for 8 hours. For the seed germination test, 50 seeds were placed on a layer of Whatman grade no. 1 filter paper (pH 7) in 90mm petri dishes and watered weekly. Seed was counted as germinated when the radical reached 2 mm. For seedling emergence test, 50 seeds were sown in lagoon soil in trays at 0.5 cm depth, which were collected from Bundala wetland complex and they were weekly irrigated with distilled water. A seedling was considered emerged when the hypocotyl was fully erect. All tests were replicated 5 times. Finally the percentage seed germination and percentage seedling emergence were calculated. Results indicate that there is a significant difference (p<0.05) between seed viability in TTC test and seed germination in petri dishes/ seedling emergence in soil trays. TTC test resulted in 87.2±7.2% seed viability, but only 51.2±2% of seedlings germinated in soil trays. Seedlings were emerged after 2 to 3 weeks of sowing. However radicals were failed to appear in petri dishes. Therefore, results conclude that even though T.angustifolia bear numerous viable seeds they show moderate percentage seed germination in wetland soils. It may be due to seed dormancy and further investigations are recommended to evaluate the effect of seed dormancy on distribution of T. angustifolia.