Botany
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Item Nutritional quality of Cavendish banana (Musa acuminata, AAA) as affected by basil oil and determination of basil oil residues by GC-MS(Journal of Science of the University of Kelaniya Volume:10, 2019) Siriwardana, H.; Abeywickrama, K.; Kannangara, S.; Jayawardena., B.The effectiveness of basil oil on the nutritional properties of Cavendish banana and chemical composition of basil oil and oil residue levels of treated banana fruits were evaluated in this study. Cavendish banana hands were treated with 1% alum (w/v), 1% alum (w/v) + 0.4% Ocimum basilicum (basil) oil, distilled water (control) and packaged in Low Density Polyethylene (LDPE) bags and stored at a cold room at 12-14ºC. After two weeks of cold storage banana were induced ripened and nutritional contents of treated Cavendish banana were determined. Gas Chromatography - Mass Spectrometry (GC-MS) was instrumental in identifying the chemical constituents of basil oil as well as residues in basil oil treated Cavendish banana peel after two weeks of storage at 12-14ºC.1 Nutritional properties of basil oil treated Cavendish banana showed no adverse changes compared to control. Methyl chavicol (estragole) was the most abundant component (74.44%) of basil oil followed by linalool (15.01%). GC-MS data revealed that negligible amount of residues of basil oil retained in treated Cavendish banana after 14 days. Basil oil treatment and subsequent modified atmosphere packaging of Cavendish banana is recommended as an ecofriendly strategy for air freight or long distance transport over land.Item Nutritional quality of Cavendish banana (Musa acuminata, AAA) as affected by basil oil and determination of basil oil residues by GC-MS.(Journal of Science 2019, Department of Botany, University of Kelaniya, Sri Lanka, 2019) Siriwardana, H.; Abeywickrama, K.; Kannangara, S.; Jayawardena, B.The effectiveness of basil oil on the nutritional properties of Cavendish banana and chemical composition of basil oil and oil residue levels of treated banana fruits were evaluated in this study. Cavendish banana hands were treated with 1% alum (w/v), 1% alum (w/v) + 0.4% Ocimum basilicum (basil) oil, distilled water (control) and packaged in Low Density Polyethylene (LDPE) bags and stored at a cold room at 12-14ºC. After two weeks of cold storage banana were induced ripened and nutritional contents of treated Cavendish banana were determined. Gas Chromatography - Mass Spectrometry (GC-MS) was instrumental in identifying the chemical constituents of basil oil as well as residues in basil oil treated Cavendish banana peel after two weeks of storage at 12-14ºC.1 Nutritional properties of basil oil treated Cavendish banana showed no adverse changes compared to control. Methyl chavicol (estragole) was the most abundant component (74.44%) of basil oil followed by linalool (15.01%). GC-MS data revealed that negligible amount of residues of basil oil retained in treated Cavendish banana after 14 days. Basil oil treatment and subsequent modified atmosphere packaging of Cavendish banana is recommended as an ecofriendly strategy for air freight or long distance transport over land.Item Morphological Characterization and Molecular Identification of Stem-end Rot Associated Fungal Species Isolated from ‘Karutha Colomban’ Mango Fruits in Sri Lanka(The Journal of Agricultural Sciences - Sri Lanka, 2019) Ekanayake, G.; Abeywickrama, K.; Daranagama, A.; Kannangara, S.Purpose: Stem-End Rot (SER) is one of the most frequently found mango postharvest diseases in many countries including Sri Lanka. Availability of a significantly detailed study on morphological and molecular characterization of the SER associated fungal species is comparatively low. The present study has been carried out considering the above fact. Research Method: SER disease associated fungi were isolated and identification was carried out using morphological characteristics. Identification was confirmed by phylogenetic analysis of newly generated ITS sequencing data using Maximum Likelihood (ML) with RAxML software (Ver.8.2.10). Findings: From the morphological studies it was observed that the fungal isolates SER1, SER2, SER3 and SER6 produced conidia on Potato Dextrose Agar. Both morphological and molecular results revealed that the isolates of SER1, SER4, SER5, and SER6 which were isolated from diseased Karutha Colomban mango fruits with SER (in Sri Lanka) belong to Lasiodiplodia sp., Nodulisporium sp., Xylaria feejeensis and Pestalotiopsis sp. respectively. Both SER2 and SER3 were confirmed as Phomopsis sp. During the present study two new fungal species (Xylaria spp. and Nodulisporium spp.) were also identified for the first time from SER of Karutha Colomban mango fruits. Research Limitations: The pathogenicity of these isolates will be tested in near future, since the study was mainly focused on the isolation and identification of the SER associated fungal species. Originality/ Value: Results of the present study will be very valuable for stakeholders in Agricultural sector, before designing control strategies at post-harvest level in order to minimize the loss and extend the storage life of mango.Item Polyaromatic Hydrocarbon Degradation of Moss Endophytic Fungi Isolated from Macromitrium sp. in Sri Lanka(David Publishing, 2016) Kannangara, S.; Ambadeniya, P.; Undugoda, L.; Abeywickrama, K.Polyaromatic hydrocarbons (PAHs), which are the major by-products of fossil fuel burning, are released to the environment with the immense growth of urbanization and industrialization. These pollutants are subsequently deposited on many substrates including plant surfaces. Due to their toxicity, mutagenicity, carcinogenicity and recalcitrant nature, they can result in many hazardous effects on human health. Application of endophytes in bioremediation has shown much promise in removing these PAHs from contaminated substrates. In the present study, an attempt was made to isolate and identify endophytic fungi from the moss plant Macromitrium sp. (frequently available) in Sapugaskanda (highly polluted) and Hettimulla (less polluted) areas in Sri Lanka. Subsequently, their potential in degrading PAHs (naphthalene and phenanthrene) was investigated. Endophytes from the moss were isolated following the surface sterilization method, and their physiological roles in degrading naphthalene and phenanthrene were carried out using plate assays, spectrophotometric and high-performance liquid chromatography (HPLC) analysis. Most of the endophytic fungi isolated from Macromitrium sp. were able to grow in Bacto Bushnell-Haas (BBH) medium incorporated with naphthalene and phenanthrene, separately, displaying colony diameters more than 30 mm. As per the results obtained from spectrophotometric and HPLC analysis, Penicillium oxalicum, Nigrospora oryzae, Aspergillus oryzae, A. aculeatus, Penicillium sp.1, Penicillium sp.5, Eupenicillium sp.2 and Mortierella sp.1 degraded both naphthalene and phenanthrene more than 85%. The findings of the present investigation provide some insight into how these endophytic fungi could be used for bioremediation of PAHs in environmental sites where contamination prevails, and also open avenues for future research in the relevant field.Item Evaluation of antifungal effect of Croton aromaticus on storage life extension of banana(2016) Dilhani, S.; Wimalasiri, S.; Abeywickrama, K.; Kannangara, S.Effect of Croton aromaticus aqueous, hot water and ethanolic leaf extracts alone and in combination with alum against banana crown rot causing fungal pathogens were investigated using 96 well plate bioassay and liquid bioassay in vitro. According to the results of 96 well plate assay, C. aromaticus aqueous extract successfully inhibited conidial germination of C. musae up to 96.9%. Percentage germination inhibition of F. proliferatum is less than that of C. musae. Hot water extract expressed higher conidial germination inhibition of F. proliferatum. Conidial germination of C. musae was 100% inhibited at the concentration of 600 (%w/v) of ethanoic extract and at the same concentration F. proliferatum was inhibited by 90.4 %. Alum was fungicidal against C. musae and L. theobromae. C. aromaticus leaf extract in combination with alum controlled F. proliferatum more effectively compared to leaf extract alone. During liquid bioassay, ethanolic leaf extract totally inhibited the mycelial growth of test pathogens at the concentration of 800 (%w/v). Among three tested extracts, ethanolic extract was most effective in inhibiting both spore germination and mycelial growth of crown rot causing fungal pathogens.Item Efficacy of basil oil and alum in controlling crown rot disease of Cavendish banana (Musa acuminata, AAA) during cold storage(2016) Siriwardana, H.; Abeywickrama, K.; Kannangara, S.; Attanayake, S.Effect of Ocimum basilicum (basil) oil spray treatment, alum in combination with modified atmosphere packaging (MAP) was investigated in extending the shelf life of Cavendish banana (Musa acuminata, AAA - Grand Naine cultivar) at 12-14 0C. Twelve week mature Cavendish banana fruits were treated with 1% (w/v) alum (Potassium aluminium sulphate), 1% (w/v) alum + 0.4% (v/v) basil oil, 0.5 g/L carbendazim and distilled water (control). Treated banana samples were packed in Low Density Polyethylene bags and stored at 12-14 0C. In-package gases were analysed every seven days up to 28 days of storage. Physicochemical properties (pH, firmness, TSS, TA), sensory properties (peel colour, flesh colour, aroma, flavour, taste, overall acceptability) and crown rot disease severity were determined in ripening induced fruits after each storage period. At the end of 28 days of storage O2 in all packages remained between 5.0- 5.4% while CO2 varied from 5.1 to 5.6%. Further, treatment of 1% alum+0.4% basil oil effectively controlled crown rot disease of Cavendish banana completely up to 21 days. Most of physicochemical and sensory properties of treated banana were not adversely affected by the treatment.Item Effect of Ocimum basilicum oil plus modified atmosphere packaging of quality of Embul banana(2016) Abeywickrama, K.; Siriwardana, H.; Kannangara, S.; Jayawardena, B.Item Disease control strategies for extending storage life of papaya (Carica papaya), cultivars ‘Red Lady’ and ‘Rathna’(2012) Abeywickrama, K.P.; Wijerathna, C.; Rajapaksha, N.; Sarananda, K.; Kannangara, S.Anthracnose (Colletotrichum gloeosporioides), stem-end rot (Lasiodiplodia theobromae) and Phomopsis rot (Phomopsis caricae-papayae) are major post-harvest diseases in papaya resulting in relatively high postharvest losses, up to 45%, in Sri Lanka. The current consumer preference is for tropical fruits free of synthetic pesticides. The objectives of the present investigation were to identify major post-harvest pathogens in papaya fruits, test in vitro fungitoxic effect of basil oil (Ocimum basillicum) and alum (sodium aluminium sulphate) on major fungal pathogens of papaya fruit and develop a relatively safe, disease control strategy. Alum (1% w/v) and basil oil (0.12– 0.16% v/v) in a liquid bioassay, indicated fungistatic and fungicidal efficacy on C. gloeosporioides, L. theobromae and P. caricae-papayae isolated from „Red Lady‟ and „Rathna‟ cultivars of papaya. In vivo investigation of fruits of both papaya cultivars harvested from fruit plantations in Sri Lanka („Red Lady‟–Yatawarawatta plantation, Kurunegala, „Rathna‟ – CIC plantation, Kekirawa and the Agricultural farm, Polonnaruwa) at 25% maturity level indicated that papaya washed in 1% (w/v) alum and subsequently sprayed with an emulsion solution of 0.16% (v/v) basil oil and enclosed in styrofoam sleeves could be stored for 14 days at 12–14 oC. The visual quality rating (VQR) was high (11–13), shriveling and „green islands‟ were low on fruits with zero disease severity where results were statistically similar to 500 mg/L Bavistin treatment. Physicochemical properties assessed were unaffected by the treatments and were comparable to the controls washed only in water. The organoleptic properties were slightly low in fruits subjected to cold temperature compared to fruits subjected to ambient temperature. No residues of basil oil could be detected on fruit peel by gas chromatography at the end of the experimental period of 14 days. The treatment strategy developed could be adopted for sea shipment or temperature-regulated supermarket storage of papaya fruits where storage life could be lengthened up to 14 days.Item Effect of alum in combination with vacuum packaging in extending the shelf life of Embul banana(Faculty of Graduate Studies, University of Kelaniya, 2015) Siriwardana, H.L.S.; Abeywickrama, K.P.; Kannangara, S.; Jayawardena, B.Crown rot disease is the major post harvest disease in Embul banana causing severe post harvest loss both in terms of quality and quantity. Due to hazardous effects of fungicides, use of eco-friendly methods of controlling crown rot disease are being investigated throughout the world. In this study, efficacy of alum (sodium aluminium sulphate) in combination with vacuum packaging was investigated in extending the shelf life of Embul banana at cold temperature. Approximately 85-day mature Embul banana hands were washed with 1% alum (w/v) solution and control was washed only in water. Treated and control fruits were packed in Low density polyethylene bags, air inside bags were removed using a vacuum and placed in fibre board cartons and stored in a cold room at 12-14 ºC. Each treatment comprised 8 replicate boxes each with 5 hands. In-package gases were analysed on initial day and every seven days thereafter up to 28 days of storage. Physicochemical and sensory properties and crown rot disease severity (CRS) were determined in ripened fruits after each storage period. Medium (50 kg) and large scale (100 kg) test marketing trials were conducted at fruit outlets in Dambulla and Kiribathgoda, Sri lanka by providing treated Embul banana samples to consumers and staff to obtain feedback on the quality of treated banana. Crown rot disease severity was low (CRS index < 1) in alum treated samples compared to control after 28 days. Physicochemical and sensory properties were unaffected by alum+vacuum packaging treatment. Oxygen within packages was maintained between 3.3 - 4.4 % while CO2 % varied between 3.9 - 4.0 %. In medium and large scale test marketing trials, treatment controlled crown rot disease to a fair extent and obtained higher score values from the customers and staff of fruit outlets for the sensory properties compared to control. Therefore, this eco-friendly treatment method could be adopted for effective control of crown rot disease and to extend shelf life of Embul banana up to one month.Item Isolation of aromatic hydrocarbon degrading phyllosphere bacteria(Sri Lanka Association for the Advancement of Science, 2013) Undugoda, L.J.S.; Kannangara, S.; Sirisena, D.M.