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

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Cyanobacterial and micro-green algal diversity in Wahawa, Mahaoya and Madunagala geothermal springs in Sri Lanka
(Research Symposium on Pure and Applied Sciences, 2018 Faculty of Science, University of Kelaniya, Sri Lanka, 2018) Madushani, K. G. P.; Athukorala, A. D. S. N. P.; Gama-Arachchige, N. S.
Geothermal springs have been recorded to exhibit a considerable diversity of cyanobacteria and microalgae. The cyanobacterial and microalgae diversity in Sri Lankan geothermal springs is understudied. The current study was conducted to determine the cyanobacteria and micro-green algae diversity of 3 springs: Wahawa (7 21́ N, 81 18 ́ E), Mahaoya (7 33.08́ N, 81 21.11́ E) and Madunagala (6 14.49́ N, 81 59.04́ E). Surface temperature and conductivity of water were recorded at 15 cm depth in 3 separate wells in Wahawa, seven and six connected wells in Mahaoya and Madunagala, respectively. The level of human activity at each location was recorded. Three or more water samples with algal mats were collected from each well. Samples were observed under light microscope within one week for identification based on morphological characters. Average temperatures of three wells in Wahawa were 410C, 430C, and 450C and conductivity was 1432 μS, 1439 μS and 1477 μS. In Mahaoya, the average temperature ranged from 430C to 540C and average conductivity was 1500 μS. In Madunagala the average temperature ranged from 380C to 440C and average conductivity was 8471 μS. Wells in Mahaoya and Madunagala are frequently used by visitors for bathing while those in Wahawa are seldom used. Eighteen different species were identified in all three springs belonging to two Divisions, Cyanophyta and Chlorophyta. Thirteen species of Cyanophyta were identified which belongs to three orders: viz Chroococcus sp., Synechococcus sp., Microcystis sp., Gleocapsa sp., Gloeothece sp., under Chroococcales, Oscillatoria sp., Lyngbya sp., Phormidium sp., Homeothrix sp. and Spirulina sp. under Oscillatoriales and Nostoc sp., Calothrix spp. and Tolypothrix sp. under Nostocales. Five species of Chlorophyta were distributed among three orders: viz Chlorella sp., Chlorococcum sp., and Oocystis sp. under Chlorococcales, Cosmarium sp. under Zygnematales and Microspora sp. under Chaetophorales. Highest diversity was observed in Wahawa springs with 17 species while six species were recorded from Mahaoya. Six species were identified from Madunagala up to date and identification is in progress. Only two species, Phormidium sp. and Calothrix spp. were recorded in all three springs while Cosmarium sp. was restricted to Wahawa. Slight temperature differences and salinity (measured as conductivity) among springs seem to affect the algal diversity, however, disturbances through human activities seem to affect the algal diversity more. In general, Wahawa, Mahaoaya and Madunagala harbour a significant algal diversity despite prevailing extreme environmental conditions.
Effect of organic and inorganic sources of fertilizer on seed germination of Solanum melongena var “Lena iri”
(Faculty of Science, University of Kelaniya Sri Lanka, 2022) Madushani, K. G. P.; Samithri, Y.A.S.; Daulagala, P.W.H.K.P.
Considering the problems associated with the use of synthetic agrochemicals, people prefer organic food. Hence there are trends toward organic farming in the world. Organic fertilizers contain the essential nutrients for plant growth, are environmentally friendly, and increase soil microbial activity. In the current study, the germination of brinjal (Solanum melongena) seeds was examined in relation to the effects of seven different types of organic fertilizers (chicken manure, cow dung, goat manure, rice husks, compost, vermicompost, and a mixture of all above), a commercial inorganic fertilizer (positive control), and a soil and coir dust mixture without the addition of any organic or inorganic fertilizer (negative control). Sieved organic fertilizers given above were mixed as follows: 50% of each type of organic fertilizer was mixed with 40% soil and 10% coir dust. The inorganic fertilizer mixture was prepared with 90% soil, 10% coir dust and 2 g (recommended by the producer) of commercial inorganic fertilizer. Negative control was prepared by mixing 90% of soil and 10% of coir dust without adding any type of organic or inorganic fertilizer. Equal amounts of soil mixtures were filled into plastic trays (30 cm x 20 cm). Each treatment and controls were tested in triplicate and arranged in a complete randomized design. Seeds (32) were sown in each tray and equal amount of water was added to each tray as required. The number of total seedlings in each replicate was counted daily for 42 days until seedlings reached to transplanting stage. Seed germination percentage and germination index were calculated, and data were statistically analyzed by using one way ANOVA test. According to the results of One-Way ANOVA test, there was a significant difference in average seed germination percentage (p = 0.001) and in average germination index (p = 0.000) among the treatments. Significantly high germination percentage and germination index were observed in negative control containing 90% of soil and 10% coir dust. This finding indicates a low impact of all types of organic fertilizers applied in germination of S. melongina seeds. A similar impact to that of negative control was also observed with commercially available inorganic fertilizer used. Compost, vermicompost and the mixture of organic fertilizers exhibited a medium germination percentage while Cow dung, Goat manure, Chicken manure, and Rice husks showed a much lower impact on seed germination percentage. When comparing seed germination rates, chicken manure showed the lowest germination rate while the other organic fertilizers exhibited medium germination rates. Only 50 % of each of the organic fertilizer was used in mixture as the seeds have some amount of stored food to be used during germination and recommended that large amounts of fertilizers are not necessary for germinating seeds. But it was evident that still the use of 50% of organic fertilizer by weight had a negative effect on seed germination of S. melongena and could be due to the phenomena called nutrient toxicity and hence application of 50% organic fertilizer is not recommended for the seed germination of S. melongena.