Browsing by Author "Senavirathna, A.M.W.K."

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    Effect of Polybag Size on Growth and Physiological Attributes of Rubber (Hevea brasiliensis) Seedlings
    (Uva Wellassa University of Sri Lanka, 2018) Gayashan, N.D.K.; Nayanakantha, N.M.C.; Seneviratne, P.; Senavirathna, A.M.W.K.; Jayasinghe, H.A.S.L.; Panditharathna, B.M.S.S.
    The annual requirement of budded rubber plants [Hevea brasiliensis (Willd. Ex A. Juss.) Mull. Arg.] has increased. Currently, finding top soil for filling polybags has become an issue in raising rubber plants. Therefore, it is essential to find ways to minimize the amount of soil usage. The present study examined the effect of the size of polybag on growth attributes of rubber seedlings for an eight-week period. The experiments were conducted in the government rubber nurseries at Egaloya (Wet Zone, LW) and Monaragala (Intermediate Zone, IL). Six bag sizes with reduced volume (3" x 15",4" x 15", 5" x 15", 4" x 13", 5" x 13" and 6" x 13") as compared to the standard size (6" x 15"-control) were used for LW whereas five bag sizes (6" x 15", 6" x 16", 6" x 17", 7" x 16" and7" x 17") as compared to control (7" x 18") were used for IL. Germinated seeds were transplanted into each polybag filled with top soil and arranged in a nursery according to a randomized complete block design (RCBD). There were 60 replicate plants for each treatment. Growth and physiological attributes of seedling viz., stem height (cm), stem diameter(mm), number of leaves, chlorophyll content (SPAD value), leaf area (cm2), stomatal conductance (gs), tap root length (cm), tap root dry weight (g), total root dry weight (g) and shoot dry weight (g)were recorded after 8 weeks from transplanting. There was no significant (P > 0.05) difference in growth and physiological attributes of seedlings raised in reduced sizes of polybags when compared to those raised in the standard sized polybags in both agro-climatic zones during the experimental period. Therefore, there is a potential to use reduced sizes of polybags to raise rootstocks of rubber while reducing the amount of soil usage.
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    Identification of Retting Enhancing Microbial Strains in Coconut Fibre Extraction
    (Uva Wellassa University of Sri Lanka, 2019-02) Thilakarathna, H.M.N.P.; Fernando, J.A.K.M.; Dharmarathne, T.T.D.; Senavirathna, A.M.W.K.
    Coir fibre is extracted from coconut (Cocos nucifera L.) husk. Natural retting process needs at least 3 months period for obtaining good quality bristle fibre. This study was carried out to reduce the retting time by introducing previously identified pectin and cellulose degrading microbial strains from bio chemical tests. For this experiment, coconut variety of CRIC60 from Bandirippuwa estate in Lunuwila was used. Retting experiments were carried out using five different combinations of microbes namely, Serratia rubidea, Bacillus safensis, Bacillus thuringiensis and Staphylococcus sciuri. The control was water. The experiment was carried out for two months. The coconut husk samples were collected by two week intervals and Ceylon drum machine was used for the fibre extraction. The percentages of bristle fibre and its qualities were analyzed. The ret liquor samples were also analyzed for pH and Electrical Conductivity. Tensile strength (118.39±1.9 N mm-2), breaking load (3.27±0.36 N), average length (127.11±2.39 mm) and fineness (27.26±3.33 g km-1) of initial sample were found to be increased to 145.48±3.97 N mm-2, 4.35±0.28 N, 152.01±2.52 mm and 57.29±1.31 g km-1, respectively with the treatment of coconut husks with Staphylococcus sciuri, Serratia rubidea, Bacillus safensis, Bacillus thuringiensis mixture for 4 to 8 weeks. Further, impurities (%) was reduced from 3.07±0.25 to 1.06±0.20 with this treatment. These values were satisfied with SLS Standards. Fibre percentage and the quality of ret liquor indicated by pH and Electrical Conductivity were also increased. Good quality bristle fibre can be obtained from coconut husks by treating with Staphylococcus sciuri, Serratiarubidea, Bacillus safensis, Bacillus thuringiensis consortium for 4-8 weeks.
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    Surface Modification of Cellulose Micro Fibrils Extracted from Banana Pseudo-Stem Using Bis-[3-(triethoxysilyl) propyl] tetrasulfide
    (Uva Wellassa University of Sri Lanka, 2019-02) Bandara, T.A.R.W.M.M.C.G.; Wijesinghe, H.G.I.M.; Alakolanga, A.G.A.W.; Senavirathna, A.M.W.K.
    Cellulose as the most abundant biomolecule on the earth, it is on investigations to be used in several applications as a remedy for the exploitation of non-renewable resources and mismanagement of agro-industrial wastes. Banana (Musa sapientum) fibre is a promising source of cellulose which can be derived after harvesting while the majority of the pseudostems are used as a low-cost feedstock for the preparation of compost. However, the cellulose itself is not compatible with most of the materials especially, with non-polar matrices. Therefore, the extracted cellulose has to be surface modified. In this study, micro-fibrillated cellulose was prepared following an alkali treatment coupled with highpressure defibrillation and acid treatments on fibre extracted from pseudo-stem. The resulted micro-fibrillated cellulose was characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and cellulose structure was confirmed. XRD studies showed 69% crystallinity of micro-fibrillated cellulose. The particle size shows a bimodal distribution where approximately 21% of the sample has an average size of 110 nm and the rest is in averaged 795 nm. The prepared micro-fibrillated cellulose was surface modified using Bis-[3-(triethoxysilyl) propyl] tetrasulfide (TESPT) following rigorous solvent extractions with ethanol and acetone through cellulose membrane. With the surface modification, the percentage crystallinity has increased up to 77.8%. Moreover, the surface modification was confirmed by the results of FTIR spectroscopy showing the stretching vibration of Si-O-C bond at 1031 cm-1 indicating that the surface modification was successful.