Ruhuna Journal of Science最新文献_第6页

Structural and functional responses of xylem in Rhizophora mucronata Lam. seedlings under drought and hypersaline conditions 根霉木质部的结构和功能响应。干旱和高盐条件下的幼苗

Ruhuna Journal of Science Pub Date : 2018-06-30 DOI: 10.4038/RJS.V9I1.38

N. Dissanayake, K. Kodikara, S. Premachandra, L. Jayatissa

{"title":"Structural and functional responses of xylem in Rhizophora mucronata Lam. seedlings under drought and hypersaline conditions","authors":"N. Dissanayake, K. Kodikara, S. Premachandra, L. Jayatissa","doi":"10.4038/RJS.V9I1.38","DOIUrl":"https://doi.org/10.4038/RJS.V9I1.38","url":null,"abstract":"Water translocation in mangrove seedlings is often affected by water stress conditions such as drought, hyper-salinities and their frequent variations. This study was therefore aimed at studying the wood anatomical responses of xylem tissue and hydraulic conductivity of Rhizophora mucronata Lam., a common species in mangrove planting, under different levels of drought [25%, ~50% and ~100% of water holding capacity (WHC)] and soil salinity [high salinity (35 psu), moderate salinity (15 psu) and freshwater (0 psu)]. As wood anatomical responses, significantly higher vessel density, vessel grouping (P<0.001) along with narrow vessel elements (P<0.001) were observed in plants grown in the 25% and 50% WHCs and high salinity treatments. All these anatomical responses are more directed towards avoidance of vessel cavitation which is commonly found under water deficit conditions. The results showed that R. mucronata plants failed to maintain efficient transportation of water when the field capacity was 50% of WHC or lower and the level of salinity was 35 psu or greater, as evident by the reduction of water conductive areas, vessel areas and hydraulic conductivity (P<0.05). Overall, water use efficiency of R. mucronata seedlings under the imposed water stress conditions has remarkably reduced and it further indicated that such imposed stress conditions directly affect the survival of planted seedlings as depicted by the significantly low survival in 25% and 50% of WHCs and high salinity. Therefore, in-depth study on lagoon hydrology including inundation levels, water depth, salinity and the selection of correct tidal positioning is highly recommended as prerequisites in mangrove planting. \u0000 \u0000Keywords. Hydraulic architecture, hydraulic conductivity, mangroves, restoration, water stress.","PeriodicalId":56207,"journal":{"name":"Ruhuna Journal of Science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46557478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Ascorbic acid retention of freshly harvested seven Nigerian green leafy vegetables after soaking in water 七种刚收获的尼日利亚绿叶蔬菜在水中浸泡后的抗坏血酸保留率

Ruhuna Journal of Science Pub Date : 2018-06-30 DOI: 10.4038/rjs.v9i1.36

S. Akande, ME Inana, EE Ugama

{"title":"Ascorbic acid retention of freshly harvested seven Nigerian green leafy vegetables after soaking in water","authors":"S. Akande, ME Inana, EE Ugama","doi":"10.4038/rjs.v9i1.36","DOIUrl":"https://doi.org/10.4038/rjs.v9i1.36","url":null,"abstract":"Vitamins are micronutrients needed in the body for important biologic functions. The current study examined the influence of steeping on vitamin C retention of seven Nigerian vegetable leaves after soaking for 8 h. One kilograme each was purchased and 6 lots of 100 g were sorte out, cleaned and treated as follow; whole leaf 1, whole leaf 2, sliced leaf 1, sliced leaf 2, sliced and salted leaf 1 and sliced and salted leaf 2. Each of the treatments 1 was soaked in 1 litre of distilled water while each of treatments 2 was soaked in 2 litres of distilled water. All treatments were kept for 8 h while monitoring the trend of reduction in vitamin C contents at 2 h intervals. Moisture (%) was determined following AOAC (2002) methods while dry matter content was estimated from moisture by calculating the difference. Ascorbic acid content (mg/100 g) was determined following the method of Ndawula et al. (2004). Result showed that; moisture, dry matter, and ascorbic acid contents of raw leaves ranged from 67.63–86.70%, 13.30–32.37%, and 103.00–1199.23 mg/100g respectively. During soaking, ascorbic acid retained by the seven green vegetables reduced as follows; 73.39–24.26% (Amaranthus viridis), 100.26–19.62% (Gnetum africanum), 129.05–27.72% (Gongronema latifolium), 66.84–7.55% (Ocimum gratissmum), 42.59–4.14% (Piper guinense), 77.38–10.26% (Pterocapus mildbedii) and 120.02–17.97% (Telfaria occidentalis). The study showed that ascorbic acid retention (%) of seven Nigerian green vegetable leaves decreased with increasing soaking duration. \u0000 \u0000Keywords: Nigeria, ascorbic acid, micronutrients, vegetable, soaking","PeriodicalId":56207,"journal":{"name":"Ruhuna Journal of Science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46523996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Optical and structural properties of CdS thin films prepared using electro-deposition technique 电沉积法制备CdS薄膜的光学和结构特性

Ruhuna Journal of Science Pub Date : 2018-06-30 DOI: 10.4038/RJS.V9I1.33

G. Mahanama, D. Madarasinghe, W. G. D. Dharmaratna, D. Jayasundara

{"title":"Optical and structural properties of CdS thin films prepared using electro-deposition technique","authors":"G. Mahanama, D. Madarasinghe, W. G. D. Dharmaratna, D. Jayasundara","doi":"10.4038/RJS.V9I1.33","DOIUrl":"https://doi.org/10.4038/RJS.V9I1.33","url":null,"abstract":"Cadmium Sulfide (CdS) thin films were electrodeposited successfully on to Indium Tin Oxide (ITO) coated glass substrates from an aqueous solution of pH 1.4 containing 0.3M CdCl2 and 0.03M Na2S2O3 or Thiourea with the aim of using in CdS/CdTe solar cells. Properties of CdS thin films prepared at different deposition voltages, deposition time periods, deposition temperatures and annealing temperatures were investigated using the current-voltage (I-V) plots. It was found that good quality CdS layers were formed under the deposition conditions of -1.13V for a period of 45 minutes in a solution of temperature at 46 oC. The performance of the CdS layers was improved significantly after annealing the samples at 400 oC for a period of 20 min. The properties of CdS thin films prepared by two and three electrode configurations and using two different electrolytes were compared using the current-voltage plots. It was found that there is a significant improvement of photocurrent of the samples prepared with two electrodes in Thiourea as the S source in comparison with the samples prepared with Na2S2O3. The analysis of XRD spectra showed the hexagonal crystal structure of CdS films confirming the quality of the films prepared by this method. In addition, absorption spectra showed band gap value of 2.42 eV proving that the samples were of good quality. Atomic Force Microscopy (AFM) analysis showed that the roughness values of CdS samples were in the range of 10-15 nm. Film thicknesses of the samples were in the range of 175-225 nm according to the optical profilometric data. \u0000 \u0000Keywords. Cadmium sulfide, electrodeposition, electrolyte, two-electrode, photocurrent.","PeriodicalId":56207,"journal":{"name":"Ruhuna Journal of Science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44784954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Spatial modelling of the householders' perception and assess the potentiality to improve the urban green coverage in the residential areas: a case study from Issadeen town Matara, Sri Lanka 户主感知的空间建模和评估提高住宅区城市绿化覆盖率的潜力：斯里兰卡马塔拉伊萨登镇的案例研究

Ruhuna Journal of Science Pub Date : 2018-06-30 DOI: 10.4038/RJS.V9I1.32

W. Ranasinghe, G. Hemakumara

{"title":"Spatial modelling of the householders' perception and assess the potentiality to improve the urban green coverage in the residential areas: a case study from Issadeen town Matara, Sri Lanka","authors":"W. Ranasinghe, G. Hemakumara","doi":"10.4038/RJS.V9I1.32","DOIUrl":"https://doi.org/10.4038/RJS.V9I1.32","url":null,"abstract":"Urban forestry has become an important concept in modern city planning for many reasons. Different forms of urban green spaces can be seen in towns as open spaces, tree belts, parks and home gardens. The main objective of this research was to assess the urban green spaces in Issadeen Town, a small residential area in Matara, Sri Lanka. A questionnaire survey was conducted in the study area covering a zone with 200 individual houses. The collected data were entered into a Geographical Information System (GIS) platform, taking one house as the unit of analysis. There was a marked difference between the numbers of trees growing in owner-occupied houses and rental houses. It was also assessed that 11% of the study area had good green cover while 8% of this area had medium level green cover that had the potential to rise to a higher category. The occupants of houses who were living in the high green cover areas stated that they had a positive perception about their environment, especially cooler temperatures. Therefore, they intended to maintain the trees in their housing plots. However, there were other occupants accounting 50.5% of the total, who were not interested or involved in the process of increasing the green cover. This is a matter that the authorities may have to address in future. \u0000 \u0000Keywords: Environmental assessment, geospatial model, green space, urban planning, urban forestry","PeriodicalId":56207,"journal":{"name":"Ruhuna Journal of Science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43766745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Jackfruit (Artocapus heterophyllus Lam.) and teak (Tectona grandis L.) leaves extracts as green corrosion inhibitors 菠萝蜜（Artocapus heterophyllus Lam.）和柚木（Tectona grandis L.）叶提取物作为绿色防腐剂

Ruhuna Journal of Science Pub Date : 2018-06-30 DOI: 10.4038/RJS.V9I1.35

Udari Kodithuwakku, M. Edussuriya

{"title":"Jackfruit (Artocapus heterophyllus Lam.) and teak (Tectona grandis L.) leaves extracts as green corrosion inhibitors","authors":"Udari Kodithuwakku, M. Edussuriya","doi":"10.4038/RJS.V9I1.35","DOIUrl":"https://doi.org/10.4038/RJS.V9I1.35","url":null,"abstract":"In this study, the inhibition effect of water and methanol extracts (WE and ME) of raw and ripe jackfruit leaves (JL) and raw teak leaves (TL) on the corrosion of mild steel (MS) in 1M HCl was studied. Weight loss measurements and potentiodynamic polarization techniques were used to investigate the behavior of the above inhibitors. The percentage of inhibition efficiency (% IE) increased with the increasing concentration of inhibitors in 1 M HCl medium. Water extract of ripe JL was found to be the most effective inhibitor and % IE was 73 at the concentration of 400 ppm. The effectiveness of other inhibitors towards corrosion in the descending order is WE of TL, ME of ripe JL, WE of raw JL, ME of TL and ME of raw JL. With the increase of the temperature, even the adsorption of the most efficient inhibitor, WE of ripe JL, decreased and the rate of corrosion increased. According to the estimated adsorption equilibrium constant, Kads and standard Gibbs free energy change, ∆G0ads, adsorption of WEs of ripe JL and TL on mild steel surface mainly observed to be by chemisorption. Potentiodynamic polarization scans have revealed the possibility of mixed type corrosion inhibition by WEs of ripe JL and TL. \u0000 \u0000Keywords. Adsorption, Langmuir isotherm, corrosion inhibitor, weight loss measurements","PeriodicalId":56207,"journal":{"name":"Ruhuna Journal of Science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46940326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0