Botany

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Antifungal activity of Croton aromatics L. in vitro, against post-harvest fungal pathogens isolated from tropical fruits
(Faculty of Agricultural Sciences, Sabaragamuwa University of Sri Lanka, 2016) Wijesundara, S.A.D.T.L.; Kannangara, B.T.D.S.P.; Abeywickrama, K.
Basil oil plus aluminium sulfate and modified atmosphere packagingcontrols Crown rot disease in Embul banana (Musa acuminata, AAB) during cold storage
(Elsevier, 2017) Siriwardanaa, H.; Abeywickrama, K.; Kannangaraa, S.; Jayawardena, B.; Attanayake, S.
tEffect of basil oil spray treatment in combination with modified atmosphere packaging was investigatedin controlling crown rot and extending the shelf life of Embul banana (Musa acuminata, AAB) at 12–14◦C.Embul banana fruits were treated with 1% aluminium sulfate, 1% aluminium sulfate + 0.4% basil oil and dis-tilled water (control). Treated banana samples were packed in Low Density Polyethylene bags and storedat 12–14◦C. In-package gases were analysed after 14 days of cold storage. Physicochemical properties,nutritional properties, sensory properties and crown rot disease severity as well as residues in treatedbanana peel were determined in ripening induced fruits. Test marketing trials were conducted in fruit out-lets in Dambulla and Kiribathgoda, Sri Lanka where treatments were provided to consumers and staff toobtain feedback on the quality of treated banana. At the end of 14 days, O2in packages remained between3.1–3.7% while CO2varied from 4.2 to 4.7%. 1% aluminium sulfate + oil treatment significantly controlledcrown rot disease compared to others. Most of the physicochemical, sensory properties of aluminiumsulfate + basil oil treated banana were not significantly different compared to control whereas nutritionalproperties of treated samples showed no drastic changes compared to control. Treated samples scoredhigher for peel colour and taste over control samples, by staff and consumers of fruit outlets. Consumerspreferred basil oil treated banana over untreated due to their sweet and pleasant taste. Insignificantamount of residues persisted in treated banana. This current safe, eco-friendly treatment strategy couldbe recommended in preparing Embul as well as other banana varieties belonging to Musa acuminata, AABgroup for commercial scale export to various destinations which require a transit time of two weeks.
Effect of Ocimum basilicum oil plus modified atmosphere packaging of quality of Embul banana
(2016) Abeywickrama, K.; Siriwardana, H.; Kannangara, S.; Jayawardena, B.
The effect of spraying essential oils of Cymbopogon nardus, Cymbopogon flexuosus and Ocimum basilicum on postharvest diseases and storage life of Embul banana
(The Journal of Horticultural Science and Biotechnology, Taylor & Francis., 2003) Anthony, S.; Abeywickrama, K.; Wijeratnam, S.W.
Embul banana hands were sprayed with emulsions of the essential oils of Ceylon citronella (Cymbopogon nardus) (0.4% v/v) lemon grass Cymbopogon flexuosus (0.16% v/v), or Indian sweet basil (Ocimum basilicum) (0.16% v/v) and stored cool (13.5 ± 1°C) or at ambient temperature (28 ± 1°C) at 94% relative humidity. A benomyl spray (0.1% w/v) was included as a standard fungicide control treatment. The effects of the essential oils on post-harvest diseases, and on organoleptic and cosmetic quality and various properties of the fruit (percentage weight loss, changes in fruit firmness, total soluble solids and titratable acidity) were determined. Treatment with Ocimum basilicum oil controlled crown rot and anthracnose, enabling bananas to be stored for up to 21 d at 13.5 ± 1°C without any detrimental effect on their organoleptic properties; results were comparable with treatment with benomyl. Rapid-ripening induced by ethral after cool storage resulted in better quality bananas. The oil of C. nardus affected the texture and flavour of the fruit and that of C. flexuosus did not give complete control of crown rot. Spraying Embul bananas with emulsions of the essential oil of Ocimum basilicum prior to cool storage can be recommended therefore as a safe, cost-effective method, with commercial potential, for controlling post-harvest diseases and extending storage life.
Effects of Fusarium moniliforme culture extracts and fumonisin B1 on DNA, RNA and protein synthesis by baby hamster kidney cells
(Springer Netherlands., 1998) Abeywickrama, K.; Bean, G.A.; Kennedy, K..A.
Baby hamster kidney cells (BHK-21) were exposed to culture filtrates of 4 Fusarium moniliforme isolates containing varying levels of fumonisin B1 (FMB1) and the effects upon RNA, DNA and protein synthesis were monitored. Cells were also grown on medium amended with FMB1 only for comparison. After 24 h incubation FMB1 (100 μg/100 ml medium) reduced protein synthesis by 4% and by 18% after 48 h. Culture filtrates containing the highest levels of FMB1 also caused the greatest inhibition in protein synthesis after 24 h but after 48 h protein synthesis levels were the same as controls even though the FMB1 level was 360 μg/100 ml. Only FMB1 reduced DNA synthesis, by 8% after 24 h but after 48 h DNA levels had increased by 40 % over controls. The culture filtrates containing the highest levels of FMB1 (360 μg/100 ml) reduced DNA synthesis more than 50% after 24 h and 48 h. Culture filtrates containing lesser amounts of FMB1 in some instances stimulated DNA synthesis and inhibited it in others. There was also no correlation in the level of FMB1 with the inhibition of RNA synthesis by BHK cells. It appears that metabolites other than fumonisin produced by F. moniliforme in culture can affect and both stimulate and inhibit RNA, DNA and protein synthesis by BHK cells.
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.
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.
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.
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.
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.
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.