ICAPS-2021
Permanent URI for this collectionhttp://repository.kln.ac.lk/handle/123456789/23880
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Item Allelopathic effects of Prosopis juliflora (Sw.) Dc. on selected crops and native plants(Faculty of Science, University of Kelaniya, Sri Lanka., 2021) Jayasinghe, J. A. C. P.; Ratnayake, R. M. C. S.Allelopathic effects of exotic plant species in natural and agricultural ecosystems have received increasing attention because of their negative impacts on native plant growth and reduction of crops yields. It was hypothesized that leaf extracts of P. juliflora have allelochemicals that could inhibit seed germination and seedling growth of the selected plants. The objective of the study was to investigate the allelopathic effects of the Prosopis juliflora leaves on seed germination and seedling growth of selected crops (Eleusine coracana, Vigna radiata) and native plants (Manilkara hexandra, Calophyllum inophyllum). The stock extract (100 gL-1) was preparedfrom P. juliflora leaves collected from Bundala National Park after five days of digestion in deionized water. The stock solution was used to prepare dilution series for applications (10.0 gL-1, 25.0 gL- 1, 50.0 gL-1, and 75.0 gL -1). The above concentrations of P. juliflora leaf extracts were separately tested for percentage seed germination, shoot lengths, root lengths, and seedling growth of the selected plant species with distilled water as the control. Seed germination percentages, root lengths, and shoot lengths results of the test species were analyzed using One-way ANOVA followed by Tukey’s test at p=005. The findings indicate that with the increasing concentration of P. juliflora leaf extracts, seed germination and seedling growth of E. coracana, V. radiata were significantly reduced. The negative effects were more visible in E. coracana than V. radiata. The lowest germination percentage of E. coracana (0.0 %) was observed when seeds were treated with 100 gL-1 and 75 gL-1 and C. inophyllum seeds were also not germinated in those concentrations. Manilkara hexandra seeds were not germinated in all concentrations of P. juliflora leaf extracts. Allelopathy was concentration-dependent and with increasing concentration of P. juliflora leaf extract, seed germination and seedling growth of C. inophyllum significantly reduced (One-way Anova, p=0.05). Hence it showed that Prosopis juliflora aqueous leaf extracts have an allelopathic effects on the seed germination and seedling growth of the selected crops and the native plants. Therefore, allelopathic effects of the aqueous leaf extracts P. juliflora need to consider in forest management and agriculture.Item Effects of Mimosa pigra and Panicum maximum extracts on the productivity of Aloe vera(Faculty of Science, University of Kelaniya, Sri Lanka., 2021) Bandaranayake, A. R. B. W. M. C. D.; Ratnayake, R. M. C. S.Aloe vera has a huge market demand locally and internationally for numerous uses. Organic A. vera farming is popular among farmers. Nutrition rich invasive alien plant species can be used for the preparation of organic liquid fertilizers (OLF). In this study, extracts of Mimosa pigra and Panicum maximum, and Musa fruit peels were used to prepare organic liquid fertilizer and it was conducted to evaluate the effects of three concentrations of the above organic liquid fertilizer on the growth and yield performance of A. vera under field conditions. Overall, there were five treatments as T1 - (0.50 g/mL of OLF), T2 – (0.75 g/mL of OLF), T3 – (1.00 g/mL of OLF) with TC (control – no fertilizer), and TS (standard – used cow dung, the typical fertilizer applied by farmers for A. vera). The pots were filled with a soil medium that contained sand, garden soil and compost (3:1:1 ratio). A. vera plants were placed under the shade of Gliricidia sepium to provide partial shade conditions. The growth and yield parameters of A. vera plants measured were plant height, leaf length, leaf width, leaf thickness, the volume of leaves, number of leaves, number of offsets, fresh weight of leaves, fresh gel weight of leaves, and percentage of gel recovery. Data were collected four months after transplantation and the data were statistically analyzed using one–way ANOVA. The T2 showed the significantly highest growth performances: length of leaves (26.34±2.21 cm), the volume of leaves (14.76 cm3±3.37), fresh weight of leaves (33.80±4.55 g/plant), fresh gel weight of leaves (24.40±4.50 g/plant), and percentage of gel recovery (67.90%±5.57) of A. vera (One–way ANOVA). These values significantly differed from TC and growth performance higher in A. vera with the application of all concentrations of organic liquid fertilizer compared to TS that used by farmers. Since T2 resulted in the highest performance for the economically important growth parameters of A. vera, the study revealed that it is the best cultivation practice for A. vera. The results have confirmed that M. pigra and P. maximum can be used for the formulation of organic liquid fertilizer for effective growth of Aloe vera as an eco- friendly, low-cost organic liquid fertilizer for the growers.Item Influence of Pinus caribaea and Alstonia macrophylla invasion on floristic composition of the buffer zone in Kottawa forest(Faculty of Science, University of Kelaniya, Sri Lanka., 2021) Dias, M. A.; Ratnayake, R. M. C. S.Kottawa forest is an isolated patch of lowland rain forest and its buffer zone is threatened by invasive alien plants ((IAS). Among IAS, wind dispersed seeds of both Alostonia macrophylla and Pinus caribaea may invade the forest gaps in the core area of Kottawa forest. The present study aimed to assess the influence of IAS at the buffer zone of the Kottawa forest in relation to the floristic composition of the area. Vegetation sampling was done using randomly selected 11 plots (10 m x 20 m) representing the forest (0.14 km2) buffer zone area. The girth at breast height (GBH), density, and frequency of plant species were enumerated. The species composition of the forest was completed by identifying the other species found outside the plots. The important value index (IVI = relative density + relative frequency + relative dominance) of species > 10 cm GBH was calculated. The percentage contribution of endemic, exotic and indigenous species to the floristic composition of the area was enumerated and it revealed that 55.1% endemic, 14.3% exotic and 30.6% native species. Pinus caribaea, Gyrinops walla, Dillenia retusa, Artocarpus nobolis, Cinnamomum verum, Alstonia macrophylla and Carissa carandas are the dominantplant species in the buffer zone. Agrostistachys hookeri, Shorea congestiflora and Dipterocarpus hispidus are the dominant endemic tree species found in the area. The most dominant species with highest relative basal area are P. caribaea and Artocarpus nobolis. the most abundant species with high relative density (11.8) is G. walla Both P. caribaea (IVI - 33.5) and A. macrophylla (IVI - 2.7) considered as IAS. The present study provides baseline information on the potential risk of A. macrophylla invasion and wide distribution of P. caribaea for native flora in Kottawa buffer zone. Therefore, the study suggests importance of managing further spread of P. caribaea and A. macrophylla in the buffer zone of the Kottawa forest with appropriate forest management practices such as assisted natural regeneration.Item An ethnobotanical approach to control Typha angustifolia: A case study from Sri Lanka(Faculty of Science, University of Kelaniya, Sri Lanka., 2021) Madushani, K. P. K.; Amarasinghe, M. D.; Ratnayake, R. M. C. S.; Dahanayaka, D. D.G. L.Typha is a cosmopolitan genus that is infamous globally for having nuisance plant species. In Sri Lanka, Typha angustifolia is distributed in both coastal and inland wetlands, including lagoons, paddy fields, and small reservoirs. Pervasive effects of Typha include hindrance to fishing activities, navigation, agriculture, human health, and ecosystem functions, especially provision of habitats for wading birds in coastal lagoons. The present study attempted to formulate an ethnobotanical strategy to control the distribution of Typha in Embilikala lagoon in Bundala National Park in Hambantota District in Southern Sri Lanka. T. angustifolia edible plant parts were tested for antioxidant activity to promote it as a phytonutrient that boosts the overall health of the body. Hexane, methanol, and aqueous extracts of leaf, leaf base, rhizome, and pollen of Typha were analyzed with DPPH and ABTS bioassays for the presence of antioxidants. Leaves were tested for their quality as raw material for making paper using the mould and deckle pouring method and couching technique. Methanol was found to be superior to hexane and deionized water as a solvent for both the assays. Leaf base (99.5±5.3 μg/mL) and rhizome (65.3±0.6 μg/mL) of T. angustifolia showed higher radical scavenging activity, and in some instances, higher than that of standard butylated hydroxytoluene (BHT) (119.3±4.5 μg/mL), indicating their potential as sources of bioactive compounds that can reduce free radicals. Contents of heavy metals (Arsenic: 0.338±0.040, Cadmium: 0.628±0.146, Chromium: 63.641±1.30, Lead: 15.657±1.70 ppb) in the rhizomes were below the standard permissible level (100.0 ppb). Pulp made with Typha leaves alone and a mixture of Typha (95%) and wastepaper (5%) were used successfully to produce writable paper. Findings suggest that T. angustifolia, which is widely considered as an invasive plant and marginally utilized currently, has a promising potential to be exploited as food and raw material to introduce new livelihoods to rural communities. This ethnobotanical approach may potentially be used to control the distribution of T. angustifolia in wetlands where it is found in invasive proportions.Item Forecasting phenological model for tropical forest species: Monoon coffeoides(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Wellassa, P. W. G. S. R.; Ratnayake, R. M. C. S.; Liyanage, U. P.Monoon coffeoides is a forest plant growing a tropical intermediate forest and pollinated by a native species of weevils in Sri Lanka. The longtime survival of both M. coffeoides and weevils is governed by its flowering and fruiting phenology. Due to a lack of phenological information implementation of proper conservation and management measures are not possible. The main purpose of this study is to analyze phenological parameters, namely, flower buds, open flowers, leaf flushing, leaf dropping, immature fruits and mature fruits of the Monoon coffeoides, to identify their correlation and variation patterns. Further, forecasting of these parameters are important in future forest management. Hence, the study has been extended to investigate the ability to forecast the parameters. Unsupervised learning techniques such as K-means clustering under Data mining are applied to identify similar behaviors among 50 trees of Monoon coffeoides. Silhouette width test was used to validate the cluster accuracy. Further, the Cross-correlation analysis was used to identify the relationships between series of phenological parameters with following delay periods as lag phases. The analysis resulted, the delay between flower buds and open flowers is 2 weeks, the delay between leaf flushing and mature fruits is 17 weeks, the delay between open flowers and immature fruits and between immature fruits and mature fruits is 5 weeks. Additionally, it was identified that the flowering and fruiting periods are varied from January to May and from March to August respectively. As the next step, phenological parameters and climate factors have been forecasted using univariate time series models. The accuracy was tested using standard tests: R-squared, Root Mean Squared Error (RMSE), Mean Absolute Percentage Error (MAPE) and Mean Absolute error (MAE). The best-fitted models for each of these parameters are; flower buds: ARMA(2,3)-GARCH(1,1), open flowers : ARMA(2,3)- GARCH(1,1), mature fruits : ARIMA(1,1,1)-GARCH(1,1), immature fruits : ARMA(1,4)- GARCH(1,1), leaf dropping : ARMA(1,1), leaf flushing : ARMA(1,1)-GARCH(1,1), average temperature : ARIMA(1,2,1) and rainfall : ARMA(3,1) respectively. All the models were significant to forecast the values and thereby, these models can be used to forecast phenological parameters.