http://ir.lib.ruh.ac.lk/handle/iruor/19197 2026-04-26T18:26:39Z http://ir.lib.ruh.ac.lk/handle/iruor/19412 Decomposition of gliricidia leaves: the effect of particle size of leaves and soil texture on carbon mineralization Walpola, B.C.; Arunakumara, K.K.I.U. Crop residues, as a reliable source of nutrients in many agro-ecosystems could minimize the dependen cy on commercial fertilizers. The particle size of crop residues is a matter of concern as it determines the accessibility of the substrate and nutrients in them to microbial attack. The present laboratory in vestigation was conducted to elucidate the effect of particle size of Gliricidia leaves (S1 ≤ 0.5 mm, S2 = 4 mm) and texture of soil (T1 = Sandy clay loam, T2 = Loamy sand) on decomposition. The highest C min eralization in Sandy clay loam soil and Loamy sand soil treated with the particle size of ≤ 0.5 mm were 134 and 241 mg/kg soil respectively. The corresponding figures for the particle size of 4 mm were 130 and 218 mg/kg soil respectively for Sandy clay loam soil and Loamy sand soil. Finer particles (≤ 0.5 mm) have shown significantly higher C mineralization than that of in coarse particles (4 mm) through out the incubation except at day 2, 7 and 14. Furthermore, C mineralization in Loamy sand soil was significantly higher than that of in Sandy clay loam soil throughout the incubation. It could be conclud ed that C mineralization was significantly influenced by the texture of soil as well as the particle size of the plant residues. 2010-02-05T00:00:00Z http://ir.lib.ruh.ac.lk/handle/iruor/19411 Formulation and quality evaluation of cordial based on kirala (sonneratia caseolaris) fruit Abeywickrama, W.S.S.; Jayasooriya, M.C.N. Kirala (Sonneratia caseolaris) is one of the tropical fruits that has received less attention from the food industry. A large number of ripen fruits are wasted during the fruiting-season. The modern preserva tion technologies can be utilized to prepare cordial from ripened kirala fruits. This study was done to develop fruit cordial from ripen kirala fruits using techniques to prevent browning and astringency taste of final product. Well-ripened fruits were treated with 500ppm Sodium Meta-bisulphide (SMS) solution for 2 minutes at 600C to prevent enzymatic browning; fruit pulp was prepared by applying maximum precaution to prevent damages to seeds while blending as the fruits contain a large number of small seeds embedded in the fleshy part. Three cordial samples were prepared according to the Sri Lanka Standard only by changing the fruit pulp concentration i.e. 250g, 230g and 200g and labeled as 110, 911 and 308 respectively. Each sample contained 350g of sugar, 0.35g of Sodium Meta-bisulphide (SMS), 2g of carboxymethylcellulose (CMC) 1.1g of citric acid and water. Prepared samples were sub jected to sensory evaluation through 35 untrained sensory panelists and best sample was selected by using Minitab software and freedman statistical analysis. The sample labeled as 911 rated as the best, with a pH 3.8, brix 52O and titrable acidity 1.39. No deterioration observed within first 30 days. The product recorded a 6 month expected expiry period. 2010-02-06T00:00:00Z http://ir.lib.ruh.ac.lk/handle/iruor/19407 Separation of tetraploid and diploid plants from chimeras in in vitro cultures of purple coneflower (echinacea purpurea l) Dahanayake, N.; Chen, Xiao-Lu; Zhao, Fu-Cheng; Yang, Yue-Sheng; Wu, Hong Doubling the chromosome number of diploid and haploid Echinacea purpurea plants have high applica ble values for genetic improvements of the crop. Field experiments have shown that the tetraploid plants grow vigorously as compared to diploid plants. Tissue culture methodology provides a useful way to separate plant chimeras into their component genotypes. In general, mutated cells are difficult to monitor but mutations which result in a change in genome chromosome number are an exception, because chromosome number mutation can be identified by chromosome counting. In the present study, chimeric materials were used as explant source, and higher percentages of tetraploid shoots were induced from explants with higher ratio of tetraploid cells to diploid cells; explants possessing 26% tet raploid cells regenerated 10% tetraploid plants, explants possessing 15% tetraploid cells regenerated 4% tetraploid plants, and explants possessing 11% tetraploid cells regenerated 2% tetraploid plants. The reliability of the tetraploid nature of the regenerated plants, directly from colchicine treated cul ture and from chimeric materials was confirmed by regenerating buds again from explants of these plants, and amongst the six plants tested, five were confirmed to be true tetraploids that regenerated 100% tetraploid plants, and the rest one to be a chimera which regenerated 93% tetraploid plants. Re sults of the experiments indicate that in vitro culture method could provide a useful way to separate chi meras into individuals with one of the component cell genome numbers, and by this it could produce 100% pure tetraploids from chimera plants for further genetic studies of Echinacea purpurea L and for direct agricultural application 2010-02-09T00:00:00Z http://ir.lib.ruh.ac.lk/handle/iruor/19406 Changes in soil water content with ambient relative humidity in relation to the organic matter and clay Leelamanie, D.A.L. Changes in soil water content with increasing ambient relative humidity was examined using model soils prepared by mixing silica sand with different types of organic matter and different types and con tents of clays. In this study, we used commercially available hydrophobic and hydrophilic organic mat ter, and kaolinite and montmorillonite under four levels of relative humidities. Soil water content of all the soils increased with increasing relative humidity. Hydrophilic organic matter, which is reported to decrease the wettability of soils, was found to increase the absorption of water into soils in the vapor form. In model soils without clay, hydrophobic organic matter, which is reported to impede water entry in liquid form (water repellent), was found to have little or no effect on water vapor absorption. In con trast, when the model soils containing 1–2% clays, hydrophobic organic matter slightly decreased the water vapor absorption. Montmorillonite containing samples showed higher water vapor absorption, and therefore, higher water contents compared with those containing kaolinite. The difference in water content between samples containing montmorillonite and kaolinite increased with increasing clay con tent. Increase in clays with high water absorption capacity was found to make the clay effects on water vapor absorption prominent and to hinder the effects of hydrophobic or hydrophilic organic matter on water vapor absorption. The absorption of water into soils in vapor form was found not to be compara 2010-02-11T00:00:00Z