http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/686 2026-04-17T09:33:45Z http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/1064 Involvement of Non-enzymatic Antioxidants in Circadian Rhythm Amplitudes of UV-C Resistance in Euglena gracilis Klebs Beneragama, C.K; Goto, K; Kumara, G.D.K Purpose : Circadian rhythms of resistance to ultraviolet (UV) irradiation help prevent UV-induced damage during daytime hours in the photosynthetic organisms. The present study was performed to identify the primary causes of these rhythms using unicellular microalgal flagellate Euglena gracilis as a model. Research Method : We examined the dose-response effects of the exogenous supplementation of 25 different antioxidants on enhancing resistance in E. gracilis to UV-C irradiation based on its immediate survival. We also compared radical scavenging and singlet-molecular-oxygen (1 O2 )-quenching activities of each antioxidant in homogeneous ethanol solutions. Findings : Several antioxidants enhanced UV-C resistance at the least resistant phase to levels greater than or equal to levels achieved physiologically at the most resistant phase, suggesting that the antioxidants (or their physiological counterparts) may be under circadian control and may be responsible for generating amplitudes of the circadian UV-resistance rhythms. We also found that the antioxidants involved were different for UV-C resistance rhythms. However, no evident relationship between the effects of antioxidants on UV resistance and their antioxidative potential was observed. Originality / Value : The study shows that the chemical properties of the antioxidants, rather than their general potencies, are responsible for generating the amplitudes of circadian UV-resistance rhythms. 2020-09-03T00:00:00Z http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/1052 Compliance of small-scale Organic Tea Farmers with Organic Standards: A Study in Sri Lanka Karalliyadda, S. M. C. B; Kazunari, T Purpose: Authenticity of organic tea has been questioned recently due to some evidence of contaminated organic tea in the market. Although producers’ compliance with organic standards (OS) is a necessity to ensure the safety of organic tea and consumers’ trust, the lack of empirical studies has become a timely need to understand the authenticity of organic tea production systems. Therefore, this study attempts to investigate the certifi ed organic tea (COT) farmers’ compliance behaviour with OS using a study in Sri Lanka. Research Method: A cross-sectional fi eld survey was conducted among 77 small-scale COT farmers in the Central and Uva provinces. These farmers were accessed through two coordinating organizations. Data was collected using interviews, structured questionnaires and observations and analyzed using descriptive statistics. Findings: Results show that higher profi ts and benefi ts from certifi cate holders are the main reasons to select COT farming than conventional tea farming. Generally, farmers perceive high discouragement violating OS and have mixed attitudes on diff erent aspects of organic farming. Farmers’ compliance behaviour towards OS is not perfect and vary among OS due to various reasons, i.e. expected loss by being noncompliant, group farming, availability of support services, fi nancial ability and awareness about hazardous contaminants. Eff ective quality assurance system and hazardous free neighbourhood potentially facilitate the farmers’ compliance behaviour. However, the unavailability of support services, lack of fi nancial capacities, and farmers’ unawareness of contaminants during handling seem to hinder the compliance. Originality: Understanding the fi rst step of COT production is novel and provide insights to implement needful actions by those who are concerned and responsible for the authenticity of COT production. 2019-01-01T00:00:00Z http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/1046 Pathogenicity of Stem-end Rot Associated Fungi Isolated from Karthakolomban Mango and Their Control by Spray and Fumigation Treatments with Selected Essential Oils Kodituwakku, T. D; Abeywickrama, K; Karunanayake, K. O. L. C Purpose: Stem-end rot (SER) is a major disease of mango that causes serious postharvest losses. Application of fungicides is environmentally unsound and is being practiced currently in its control. This study was conducted to develop essential oil treatment systems as eco-friendly strategies to control SER of Karthakolomban mango and to determine the pathogenicity of several SER associated fungi. Research Method: Pathogenicity of four fungal isolates in SER was assessed by inoculating them on Karthakolomban mango fruits. Karthakolomban mango fruits were subjected to spray and fumigation treatments using four essential oils and their pathological, physicochemical and sensory properties were evaluated after a 8-day storage at 12 – 14 ºC. Findings: Lasiodiplodia theobromae, Pestalotiopsis sp., Phomopsis sp. and Xylaria feejeensis were the major SER pathogens of mango. X. feejeensis was identifi ed as a SER pathogen for the fi rst time in Sri Lanka. Spray and fumigation treatments conducted using basil, clove, cinnamon leaf and cinnamon bark oils eff ectively controlled SER of Karthakolomban mango stored at 12 – 14 ºC for 8 days. Mango sprayed with 1.6 µL/mL cinnamon bark oil has displayed no SER after induced ripening. None of the treatments caused drastic alterations in physicochemical and sensory properties of mango. Research Limitations: Storage period of mango was restricted to 8 days due to the initiation of natural ripening which was the major limitation to achieving a further enhanced shelf life. Originality/value: The treatment strategies developed by this research could be commercialized as biosafe SER control strategies in reducing postharvest losses of mango in the local and international trade 2019-01-01T00:00:00Z http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/1041 Does Contract Farming Enhance Income of Farmers? Evidence in Tea Production of Vietnam Nguyen, Anh Tru Purpose: The theme of eff ects of contract farming on income of farmers has been strongly debated by scholars in recent years, especially in developing countries. This article attempts to investigate the infl uence of contract farming on the income of farmers in tea production in Phu Tho province of Vietnam. Research Method: Primary data for the study is gathered by a cross-sectional survey on 358 tea farmers in fi ve districts of Phu Tho province between March and June 2016. Propensity score matching is employed to assess eff ects of contract participation on income of tea farmers in Phu Tho province, Vietnam. Findings: Our results suggest that contract farming can have a minor positive impact on farmers’ incomes. The average income of contracted farmers is found to be higher than that of their counterparts by about US$720 per year. Due to this small diff erence of income, contract farming plays an important role in procuring leaf tea, stabilising prices of leaf tea and generating employment rather than enhancing income for tea farmers. Originality/value: The research contributes to the empirical work by providing an evidence on infl uences of contract farming on income of tea farmers as well as re-examining the importance of contract farming to improving livelihood of tea farmers in Phu Tho province, Vietnam. 2019-01-01T00:00:00Z