Browsing by Author "Beneragama, C. K"

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Embargo
Biomonitoring of HgCl2 with Dracaena sanderiana under Two Different Irradiance Levels: Effects on the Photosynthetic Apparatus
(Faculty of Humanities and Sciences,SLIIT, 2021-09-25) Jayasooriya, L. S. H; Wijethunga, W. M. U. D; Kumarihami, H. M. P. C; Attanayake, U; Beneragama, C. K
Heavy metals such as Hg are phytotoxic. Interference of heavy metals with photosynthesis has been a topic of intensive research during the last few decades. Some plants can be used in biomonitoring and the remediation of such pollutants. It is important to assess the biomonitoring potential in ornamental plants as they do not enter into the food chain. This experiment was conducted to examine the effect of HgCl2 on the photosynthetic apparatus in Dracaena sanderiana to assess its potential to use in biomonitoring. D. sanderiana cuttings were subjected to heavy metal stress (100 μM HgCl2), along with control (distilled water) under two contrasting irradiance levels (High light-: 22,500±2,000 lux and Low light-: 750±200 lux). OJIP chlorophyll fluorescence measurements were conducted using a fluorometer (FluorPen, FP-110). The measurements were recorded four times a day (9 am, 12 noon, 3 and 6 pm) continuously for four days after imposing the treatments. Specific energy fluxes per reaction center, flux ratios and Performance Index (PI) were recorded. There was a significant reduction in PI, maximum quantum yield of primary photochemistry (φPo) and quantum yield of electron transport (φEo) with the time in HgCl2 treatment compared to the control. This indicates the negative effects of Hg+ on the photosystem II. However, the visual rating of the foliage quality was at a satisfactory level. Moreover, there was a significant increase/progress/growth in effective antenna size (ABS/RC) and maximum quantum yield of nonphotochemical de-excitation (φDo) in HgCl2 with time. Except in electron transport efficiency (ψo), a clear unimodal circadian variation was observed in all OJIP parameters under high light condition. Photosynthetic apparatus of D. sanderiana is affected by the Hg+. However, the plant was able to cope up with the heavy metal stress during the experimental period indicating that, it can successfully be employed in short-term biomonitoring of mercury. In the experiment, the temperature effect could not be eliminated, thus future experiments for studying that might be crucial.
Embargo
The effect of different ethylene concentrations on different maturity stages on the postharvest quality of Cavendish banana (Musa acuminate) cultivar, ‘Grande Naine’
(Faculty of Humanities and Sciences,SLIIT, 2021-09-25) Subasinghe, S. M. J. C; Kodithuwakkuge, V. N; Attanayake, U; Wasala, W. M. C. B; Dammullage, I; Beneragama, C. K
Banana is one of the most cultivated fruit crops in Sri Lanka and 5% of total production is exported. Due to a lack of knowledge on harvesting maturity, artificial ripening and other postharvest technologies, 20% of the yield is lost during the post-harvest handling of banana. This study was conducted to examine the effect of application of different ethylene concentrations at different maturity stages on postharvest quality of Cavendish banana (Musa acuminate) cultivar ‘Grande Naine’ under tropical climate conditions. Mature bananas combs (hands) at twelve weeks, thirteen weeks and fourteen weeks after flowering were exposed to 0, 85 and 170 ppb of ethylene gas for 24 hours at 24 ˚C and under 75% RH. Different physicochemical properties were obtained and analyzed statistically. There was a significant interaction effect between the maturity stage and ethylene concentration on weight loss, TSS and pH at the table-ripe stage. The fruits lost weight steadily down to 8.5%, possibly because of the rapid rates of metabolism as well as water loss. Meanwhile, TSS increased from 4% to 20% and pH decreased gradually with the ripening of banana. The results revealed that the best stage of maturity for harvesting Cavendish bananas is at 11-12 weeks after flowering for improved physicochemical and sensory properties at the table ripe stage. Further, it can be concluded that the use of ethylene concentration of 85 ppb for ripening Cavendish banana instead of the higher concentrations that are commercially applied, would be cost-effective without decreasing the fruit quality.
Embargo
Evaluation of the Scenic Beauty of the Existing Landscape of Southern Expressway and Suggestions to Improve the Landscape Using GIS and Remote Sensing
(Faculty of Humanities and Sciences,SLIIT, 2021-09-25) Marasinghe, M.D.U; Gunawardena, A. R; Senevirathne, S. M. P; Dilrukshi, R. P. W. A; Hettiarachci, M. H. S. M; Dissanayaka, D. M. N. S; Attanayake, U; Beneragama, C. K
The occurrence of landslides, frequent accidents and negative impacts on environmentally sensitive areas are some of the issues associated with the Southern Expressway in Sri Lanka. Most of these issues could be resolved through proper landscape designing along the highway. This study was intended to assess the existing landscape and land cover/use types of the Southern Expressway using GIS and remote sensing. Study area boundary of 1 km buffer zone along the expressway was demarcated and existing land cover/ use types and environmental sensitive areas were identified. Using “Landsat 8 imageries”, a map was developed based on Normal Difference Vegetative Index (NDVI) values within the buffer zone. Landscape models were developed and a visual preference survey was conducted using a focus group of 30 people. Results revealed that the expressway is surrounded by environmentally sensitive areas, archaeological reserves, protected ancient monuments, landslide prone areas, hydrological areas, forest and wild life reserves. The greenness varied throughout the buffer zone. The visual preference survey revealed that the respondents preferred more natural landscape designs which fully or partially cover the residential areas and natural designs that fully screen the religious areas along the highway. Respondents mostly preferred to have landscape designs which express the importance of the area with clear interpretative labelling. Visual preference survey suggests that there is a need of area-specific landscape designs for the Southern Expressway and the importance of human perception-based methods in designing landscape.
Embargo
Probing the Effect of Salicylic Acid on the Post-harvest Changes in Cordyline fruticosa Using OJIP Chlorophyll Fluorescence Transient Analysis
(Faculty of Humanities and Sciences,SLIIT, 2021-09-25) Wijethunga, W. M. U. D; Jayasooriya, L. S. H; Kumarihami, H. M. P. C; Dissanayake, U; Beneragama, C. K
Use of proper postharvest treatment is vital to ensure a longer postharvest life in ornamental plant production including cut-foliage. Although Salicylic Acid (SA) is a promising postharvest treatment, to maintain postharvest quality of many cut foliage species, its direct impact on the photosynthetic process has debatable outcomes as reported by various researchers. In this study, we attempted to investigate the effect of SA on the postharvest performance in cut foliage using OJIP analysis. Two concentrations of SA (100 and 300 mg/L) with a watercontrol were tested with cut-leaves of Cordyline fruticosa var Willy’s gold at room temperature (25±2°C). OJIP parameters, i.e., specific energy fluxes (ABS/RC, TR/RC, ET/RC, and DI/RC), flux ratios (maximum quantum yield of primary photochemistry-φPo), electron transport efficiency (ψo), quantum yield of electron transport (φEo), and performance index (PI) were recorded every other day using a fluorometer (FluorPen FP). Leaf chlorophyll, anthocyanin contents were also determined using spectrophotometry. Data were analysed according to completely randomized design (CRD). The PI increased in both SA treatments up to the 7th day of treatment. SA at 300 mg/L had a significant effect on most of the OJIP parameters, specific fluxes in particular. SA treated leaves exhibited higher on the retention of chlorophyll. Except φPo all other flux ratios were significantly affected by the SA treatment indicating its impact on the photosynthetic apparatus but most probably in retarding the ethylene biosynthesis as reported elsewhere. SA extends the vase life of Cordyline fruticosa cut leaves. Moreover, there is an effect of SA on the photosynthetic machinery; net photosynthesis proved the OJIP results. The underlying mechanism warrants further studies.
Open Access
Research and development and innovations in floriculture: lessons from the market giants for developing countries like Sri Lanka
(2015-05-01) Beneragama, C. K; Peiris, S
Floriculture has become one of the growing industries in the present world. In the year 2013, the global floriculture exports reached US$ 21.6 billion while showing a 22% increase over the past five years. Sri Lanka being a small island, has not shown a rapid growth in the floriculture business over the past five years, the country has been a continuous supplier of floriculture produce to the world market, reaching its total floriculture trade value worth Rs. 14.1 million in 2013. Among the floriculture assortment that the country produces for the world market at present, cut foliage/tops (~53%), live plants including rooted cuttings (~44%), cut flowers (~1.5%) and flower seeds (~1%) are the four main items, dried flowers and other decorative floriculture items also in minor quantities. One of the biggest constraints that Sri Lanka faces is the insufficient investments on large scale floriculture ventures, making most of the businesses medium- to small-scale. To thrive in the global business the scale of production matters. Moreover, we have mostly been depending on the available varieties for ages. Therefore, it is high time for the country to think about the competitive novel varieties. Even though the people are knowledgeable with higher literacy rates, until now, the postharvest handling of floricultural produce has not been practiced satisfactorily. Besides, the facilities available for training, research and innovation are insufficient to support the growth of the industry.