Plant and Molecular Biology

Permanent URI for this collectionhttp://repository.kln.ac.lk/handle/123456789/22641

Browse

Now showing 1 - 20 of 63

An analysis of regional variations in the physicochemical properties of Cocos nucifera L. var. nana across Sri Lanka
(2024) Pavalakumar, Dayani; Undugoda, Lanka Jeewanie Samarakoon; Thambugala, Kasun Madhusanka; Manage, Pathmalal Marakkale; Ruwani, Nilushi Nugara; Kannangara, Sagarika Dilpushpi; Rajapaksha, Suranga M.
This study explores the intriguing regional disparities in the characteristics of green dwarf tender coconut water (Cocos nucifera L. var. nana) in Sri Lanka. Physicochemical parameters of coconut water subjected to a comprehensive analysis following standard AOAC methods. The prevalent sugar types in the samples were identifed as fructose and glucose, with a minute amount of sucrose using High-Performance Liquid Chromatography (HPLC). Notably, regional diferences in sugar profles were observed during the analysis. Kurunegala samples exhibited signifcantly higher levels of total soluble solids (5.98±0.12°Brix), along with elevated total sugar (70.13±5.06 mg mL−1), total reducing sugar (68.53±5.57 mg mL−1), glucose (39.65±6.10 mg mL−1), and fructose (37.65±7.12 mg mL−1), while Colombo samples demonstrated the least values. Regarding pH values, Colombo samples exhibited a signifcantly lower value (4.87±0.10). Furthermore, a significant quantity of macro minerals such as calcium, sodium, potassium, and magnesium, along with trace minerals like iron and zinc, were identifed. Fourier-transform infrared spectroscopy analysis indicated the presence of functional groups from simple sugars and phenolic compounds as major chemical bonds for all regions. Principal Component Analysis was performed considering the Electronic Nose (E-nose) data, revealing distinctive volatile profle clusters for Kurunegala and Colombo samples. Moreover, sensory evaluations confrmed Kurunegala as the most preferred, while Colombo was ranked as the least preferred in terms of organoleptic characteristics. These fndings underscore the critical importance of regional variations in the nutritional content and sensory attributes of coconut water, which play a pivotal role in infuencing customer preferences.
Anammox bacteria in treating ammonium rich wastewater: Recent perspective and appraisal
(Bioresource Technology, 2021) Weralupitiya, C.; Wanigatunge, R.; Joseph, S.; Athapattu, B. C.; Lee, T. H.; Kumar Biswas, J.; Ginige, M. P.; Shiung Lam, S.; Senthil Kumar, P.; Vithanage, M.
The discovery of anammox process has provided eco-friendly and low-cost means of treating ammonia rich wastewater with remarkable efficiency. Furthermore, recent studies have shown that the possibility of operating the anammox process under low temperatures and high organic matter contents broadening the application of the anammox process. However, short doubling time and extensive levels of sensitivity towards nutrients and environmental alterations such as salinity and temperature are the limitations in practical applications of the anammox process. This review article provides the recent yet comprehensive viewpoint on anammox bacteria and the key perspectives in applying them as an efficient strategy for wastewater treatment.
Assessing the antioxidative potential of lactic acid bacteria inhabiting tender coconut water
(Faculty of Graduate Studies - University of Kelaniya, Sri Lanka, 2023) Pavalakumar, D.; Undugoda, L.J.S.; Manage, P.M.; Nugara, R.N.; Kannangara, S.
Probiotics are renowned for their beneficial impact on human health, including their antioxidative properties. Lactic acid bacteria (LAB), which constitute a major group within probiotics, have been recognized for their ability to act as potent antioxidants, providing relief from oxidative stress in the host. This study aims to evaluate the antioxidative activity of probiotic LAB inhabiting the tender coconut water samples collected from different regions of Sri Lanka. In a previous study, analysis of the collected tender coconut samples resulted in the identification of four potential probiotic strains at the species level: Lactiplantibacillus plantarum CWJ3, Lacticaseibacillus rhamnosus CWKu12, Lacticaseibacillus paracasei CWKu14, and Lacticaseibacillus casei CWM15. The antioxidative activities of these strains were evaluated using four different chemical antioxidant assays: the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay at 517 nm, the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay at 734 nm, the ferric reducing antioxidant power (FRAP) assay at 593 nm, and the total phenolic content (TPC) assay at 765 nm through spectrophotometric method. Three different concentrations of each bacterial strain (107, 108, and 109 CFU mL-1) were prepared using overnight grown cultures in deMan, Rogosa, and Sharpe broth at 37 °C, included in the study. The results indicate a significant increase (p < 0.05) in antioxidative activity for all four strains across all analyzed methods with an increase in cell concentration. Lactiplantibacillus plantarum CWJ3 exhibited the highest antioxidative potential at 109 CFU mL-1, with 88.85±0.84% radical scavenging activity in the DPPH assay, 84.0±0.14% radical scavenging activity in the ABTS assay, 0.029±0.004 mg mL-1 ascorbic acid equivalent in the FRAP assay, and 0.0052±0.0006 mg mL-1 gallic acid equivalent in the TPC assay. Conversely, Lacticaseibacillus paracasei CWKu14 demonstrated the lowest values for all antioxidative activities. Continued research on the antioxidative properties of probiotic LAB derived from tender coconut water holds promising prospects for the development of functional beverages.
Biocontrol potential of endophytic fungi in tea (Camellia sinensis (L.) Kuntze) leaves against selected fungal phytopathogens
(Malaysian Journal of Microbiology, 2022) Thambugala, K.; Daranagama, D.; Kannangara, S.
Aims: Endophytic fungi are a diverse group of microorganisms that stay asymptomatically in the healthy tissues of the host. Many fungal endophytes are associated with the tea plant (Camellia sinensis) and the pathogens of the tea plant have the potential to grow as endophytes or act as latent pathogens during the initial growth of the plant. The present study aimed at screening tea endophytic fungi with the potential for control of a few critical phytopathogens, Fusarium sp., Lasiodiplodia theobromae, Pestalotiopsis sp. and Sclerotinia sclerotiorum while evaluating the efficiency of growth inhibition of these phytopathogens by the endophytic fungal isolates using in vitro assays. Methodology and results: Five endophytic fungal strains; Colletotrichum gloeosporioides, C. siamense, Daldinia eschscholtzii, Pseudopestalotiopsis chinensis and Phyllosticta capitalensis isolated from leaves of C. sinensis in Sri Lanka were evaluated for growth inhibition against plant pathogens; Fusarium sp., L. theobromae, Pestalotiopsis sp. and S. sclerotiorum using the dual culture assay and volatile compound-mediated inhibition assay. All the fungal endophytes used in this study exhibited antifungal activity against Fusarium sp., Pestalotiopsis sp. and S. sclerotiorum in the dual culture assay on PDA. Daldinia eschscholtzii (67.30%) and C. gloeosporioides (61.54%) showed strong antagonistic activity against S. sclerotiorum, while P. capitalensis (42.30%) demonstrated moderate activity. All the endophytic fungal strains showed moderate antifungal activities against Fusarium sp. The percentage growth inhibitions of Pestalotiopsis sp. by all the endophytic isolates tested were below 25.00%. In the volatile compound-mediated inhibition assay, none of the endophytic isolates showed visible inhibition against the phytopathogens used. Conclusion, significance and impact of study: In this study, the fungal endophytes which showed potential antagonistic activity against the tested phytopathogens can be used to develop commercialized products of fungal biocontrol agents (BCAs) for controlling plant fungal diseases.
Bioremediation and sustainable mushroom cultivation: harnessing the lignocellulolytic power of Pleurotus species on waste substrates
(2024) Nawarathne, Irani Yasora; Daranagama, Dinushani Anupama
Mushrooms, a diverse group of fungi, has captivated human interest for centuries due to their intriguing characteristics and versatile application. The nutritional profile, coupled with unique organoleptic qualities, renders mushrooms not only a culinary delight, but also a valuable component of a balanced diet. In addition, mushrooms have gained recognition for their medicinal properties due to certain compounds found within them that exhibit promising pharmacological activities. Among the edible mushrooms, the Oyster mushroom (Pleurotus spp.) is commercially important in the global mushroom market and is widely cultivated and consumed in various parts of the world. Beyond the culinary appeal and medicinal properties of Pleurotus species, their cultivation holds an important environmental significance. These mushrooms are efficient decomposers of lignocellulosic biomass, contributing to agricultural and forestry waste recycling. Many researchers have demonstrated how their cultivation can serve as a sustainable practice, reducing the environmental impact of organic waste while generating a valuable food resource. In Sri Lanka, oyster mushroom cultivation is practiced on a small scale as a self-employed cottage industry. Four main species of oyster mushrooms, namely P. djamor, P. eous, P. ostreatus, and P. cystidiosus, are commercially cultivated in Sri Lanka. Obtaining an efficient, cost-effective, and sustainable substrate is a key factor in promoting the mushroom industry within the country, ensuring export-quality mushroom production. Recently, there have been some attempts to use unconventional substrate materials, such as used diapers, as an innovative and eco-friendly approach, where the high cellulose content of diapers serves as a substrate for fungal growth, while, repurposing problematic non-biodegradable waste streams for agricultural practices. a.
Can Anaerobic Soil Disinfestation (ASD) be a Game Changer in Tropical Agriculture?
(Pathogens, 2021) Priyashantha, A.K.H.; Attanayake, R.N.
Anaerobic soil disinfection (ASD) has been identified as an alternative soil-borne pathogen control strategy to chemical fumigation. ASD involves the application of an easily liable carbon source followed by irrigation to field capacity and maintenance of an anaerobic condition for a certain period. A literature search undertaken on ASD found that more than 50 comprehensive research projects have been conducted since its first discovery in 2000. Most of these studies were conducted in the USA and in the Netherlands. Though the exact mechanism of ASD in pathogen control is unknown, promising results have been reported against a wide range of pathogens such as fungi, nematodes, protists, and oomycetes. However, it is interesting to note that, except for a few studies, ASD research in the developing world and in the tropical countries has lagged behind. Nevertheless, with soil quality depletion, reduction in arable lands, and exponential population growth, a drastic change to the current agricultural practices should be adapted since yield gain has reached a plateau for major staple crops. Under such circumstances, we identified the gaps and the potentials of ASD in tropical agricultural systems and proposed promising biodegradable materials.
Can infectious modeling be applicable globally: Lessons from COVID-19
(Current Opinion in Environmental Science & Health, 2022) Magana-Arachchi, D.; Wanigatunge, R.; Vithanage, M. S.
Contagious diseases are needed to be monitored to prevent spreading within communities. Timely advice and predictions are necessary to overcome the consequences of those epidemics. Currently, emphasis has been placed on computer modeling to achieve the needed forecasts, the best example being the COVID-19 pandemic. Scientists used various models to determine how diverse sociodemographic factors correlated and influenced COVID-19 Global transmission and demonstrated the utility of computer models as tools in disease management. However, as modeling is done with assumptions with set rules, calculating uncertainty quantification is essential in infectious modelling when reporting the results and trustfully describing the limitations. This article summarizes the infectious disease modeling strategies, challenges, and global applicability by focusing on the COVID-19 pandemic.
Carbon stocks in mangrove ecosystems of Sri Lanka: Average contributions and determinants of sequestration potential
(Elsevier, 2024) Perera, K.A. Roshan S.; de silva, Wasana; Amaransinghe, Mala D.
Mangroves are crucial in carbon sequestration despite covering only a small percentage of the Earth's surface. Latitudinal gradient primarily determines the distribution of climatic zones of distinct sunlight, temperature, and precipitation patterns, which influence the community structure of the mangrove ecosystem. The tropical climate of Sri Lanka contributes to the island's lush mangrove forests. The present study estimated that the average island's carbon sequestration capacity of Sri Lankan mangrove ecosystems is 524.25 t/ha representing a substantial volume of carbon storage that contributes to offset greenhouse effect due to increasing atmospheric CO2. Our results substantiated that rainfall positively influences total carbon sequestration capacity of mangrove ecosystems. It was also revealed that a positive relationship exists between vegetation structural complexity and sediment organic carbon, highlighting the influence of vegetation structure, that is primarily dependent on climatic conditions, on production of organic matter and sediment carbon sequestration. Globally, the carbon sink function of mangrove ecosystems is reported to be highest in the tropical areas and it declines towards sub-tropical higher latitudes while those in the southern hemisphere perform better carbon sinks than those in the northern hemisphere. The vertical distribution of total organic matter content in mangrove sediments was revealed to be in a descending order, manifesting the weak tidal removal of surface organic matter under the microtidal conditions in Sri Lankan marine waters, thus qualifying mangrove ecosystems in microtidal coasts as effective carbon sinks.
Carbon stocks in mangrove ecosystems of Sri Lanka: Average contributions and determinants of sequestration potential
(Ocean & Coastal Management, 2024-09) Roshan, K. A.; Wasana, de silva; Amaransinghe, M. D.
Mangroves are crucial in carbon sequestration despite covering only a small percentage of the Earth's surface. Latitudinal gradient primarily determines the distribution of climatic zones of distinct sunlight, temperature, and precipitation patterns, which influence the community structure of the mangrove ecosystem. The tropical climate of Sri Lanka contributes to the island's lush mangrove forests. The present study estimated that the average island's carbon sequestration capacity of Sri Lankan mangrove ecosystems is 524.25 t/ha representing a substantial volume of carbon storage that contributes to offset greenhouse effect due to increasing atmospheric CO2. Our results substantiated that rainfall positively influences total carbon sequestration capacity of mangrove ecosystems. It was also revealed that a positive relationship exists between vegetation structural complexity and sediment organic carbon, highlighting the influence of vegetation structure, that is primarily dependent on climatic conditions, on production of organic matter and sediment carbon sequestration. Globally, the carbon sink function of mangrove ecosystems is reported to be highest in the tropical areas and it declines towards sub-tropical higher latitudes while those in the southern hemisphere perform better carbon sinks than those in the northern hemisphere. The vertical distribution of total organic matter content in mangrove sediments was revealed to be in a descending order, manifesting the weak tidal removal of surface organic matter under the microtidal conditions in Sri Lankan marine waters, thus qualifying mangrove ecosystems in microtidal coasts as effective carbon sinks.
Co-occurrence of Geogenic, Microbial, and Anthropogenic Emerging Contaminants: Ecotoxicity and Relative Environmental Risks
(Springer, 2022) Magana-Arachchi, D.N.; Wanigatunge, R.P.
Heavy metals, 1,4-dioxane, cyanotoxins, bacteria with antibiotic-resistant genes, pharmaceuticals, nanoparticles, and many more are listed as emerging contaminants due to their toxicity whether their origin is geogenic, microbial, or anthropogenic. These specific types of environmental impurities, at present, are excluded from regular scrutinizing programs but are potential nominees for future supervision and management subjected to their hazardous nature, community awareness, incidence, and depending on the amount present in distinct environments. A chemical or an organism does not need to be novel to be groped as an emerging contaminant. Primarily, these impurities had been in nature for decades, but their impact is being assessed only now. When these three types of pollutants coexist together the adverse impact they create on Mother Nature is enormous. With increasing population growth and with rapid urbanization, release of these contaminants gets accelerated and considered as a global issue. Due to their perseverance, in aquatic environments, they get accumulated in biota thereby contaminating the food web and humans and animals mostly get exposed through the food chain or by drinking the contaminated waters. This chapter focuses on emerging contaminants of geogenic, anthropogenic and microbial origin, their coexistence in the environment, ecotoxicity, and relative environmental risks.
Coastal protection function of mangrove ecosystems: a case study from Sri Lanka
(2023) De Silva, Wasana; Amarasinghe, Mala Damayanthi
The Indian Ocean tsunami in 2004 revealed the inferiority of hard engineering solutions in coastal protection and provided sound evidence over the potential of coastal vegetation, particularly mangroves in protecting the coast against erosion, tropical storm surges, and occasional natural calamities like tsunamis. The present study was initiated therefore to determine the extent to which mangroves could be used to protect the coasts against damage by tsunamis. The structure of mangrove vegetation at Kirinda, Kalametiya, and Rekawa in Sri Lanka that resisted tsunami waves for varying extents in 2004 was studied in detail to discern the wave attenuation function of mangrove vegetation. Vegetation structure is a salient factor that contributes to reduction of the impact of natural disturbances to which mangrove ecosystems are vulnerable. The current study highlights that mangrove parameters such as canopy, trunk, and complex root system and wave parameters such incident wave height and inundation distance play vital role in mangroves-induced wave attenuation. The study found that tsunami run-up height and tsunami inundation distance were negatively correlated with tree volume, forest width and tree height whereas that was positively correlated with porosity of the mangrove vegetation. Depth of sedimentation caused by tsunami waves decreased across the mangrove vegetation from the proximal end (in relation to the advancing wave) to the distal end at all mangrove study sites indicating the progressive dissipation of energy of the wave. The mangrove plant communities comprised of Avicennia marina, Ceriops tagal, Excoecaria agallocha and, Rhizophora mucronata evidently, have served as natural coastal barriers and contribute to mitigate impacts of natural disturbances such as tsunamis and tropical storms. As such our study revealed that the effectiveness of coastal bio-shields is based on the make-up of the coastal forests.
Common methods and outcomes of employee engagement: a systematic literature review towards identifying gaps in research
(National Science Foundation of Sri Lanka, 2023) Priyashantha, K. G.; De Alwis, A. Chamaru; Welmilla, I.
As global surveys reported, employee engagement is currently in crisis. Hence, this study aimed to discover (1) common methods and outcomes of employee engagement and (2) researchgaps relating to employee engagement. The study employed the Systematic Literature Review (SLR) methodology. Publications selected for this review were based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, as it is recommended for SLRs. The review included two 260 studies published in Scopus from 2008 to 2021. The studies were analysed through bibliometric analysis for reviewing purposes and achieving the two objectives. Findings indicate different methods and outcomes of employee engagement.
Cyanotoxins uptake and accumulation in crops: Phytotoxicity and implications on human health
(Toxicon, 2022) Weralupitiya, C.; Wanigatunge, R. P.; Gunawardana, D.; Vithanage, M.; Magana-Arachchi, D.
The invasive nature of cyanotoxin-producing cyanobacteria and the adverse effects concerning their toxic impacts have gained heightened scientific attention of late. The persistence of cyanotoxins in irrigation water leads to bioaccumulation in plants, the development of phytotoxic effects, and the threat of groundwater contamination. The accumulation of cyanotoxins in plants is caused by several factors leading to severe toxic effects, including reduced plant growth and seed germination, enhanced oxidative stress, lowered rate of mineral uptake, decreased photosynthetic efficiency, and loss of chlorophyll content. The uptake and accumulation of cyanotoxins in plants can be concentration-dependent, as reported in a myriad of studies. Even though several studies have reported phytotoxic effects of cyanotoxin contamination, field-related studies reporting phytotoxic effects are particularly inadequate. Paradoxically, at realistic conditions, some plants are reported to be tolerant of cyanotoxins. Furthermore, the breadth of adverse impacts of cyanotoxins on human health is significant. Cyanotoxins cause major health effects including cancer, oxidative stress, organelle dysfunction, DNA damage, and enzyme inhibition. This review intends to present compelling arguments on microcystins (MCs), cylindrospermopsins (CYN), β-N-methylamino-L-alanine (BMAA), and anatoxin-a (ANTX-a), their uptake and accumulation in crop plants, phytotoxic effects on plants, and potential health implications to humans. The accumulation of cyanotoxins implants cultivated as food crops, resulting in phytotoxic effects and adverse impacts on human health are serious issues that require scientific inputs to be addressed.
Depolymerization of polyaromatic hydrocarbons by Penicillium spp. inhabit the phyllosphere of urban ornamental plants
(Environmental Quality Management, 2022) Dharmasiri, R. B. N.; Undugoda, L. J. S.; Nilmini, A. H. L.; Pathmalal, M. M.; Nugara, N. N. R. N.; Udayanga, D.; Kannangara, S.
A variety of anthropogenic sources release hazardous polyaromatic hydrocarbons (PAHs) into the phyllosphere which is an excellent niche for diverse fungi, and some of them have PAHs degradation capabilities. Therefore, this research attempted to determine the PAHs (phenanthrene, anthracene, naphthalene, and pyrene) degradation capability of phyllosphere inhabited Penicillium species. The leaf samples were collected from highly polluted urban areas (Panchikawatta, Pettah, Orugodawatta, Maradana, Sapugaskanda, and Colombo Fort) in Sri Lanka to isolate fungal species inhabiting the phyllosphere. Furthermore, their distribution patterns among the leaf tissue layers were studied using bright-field microscopic observations. Moreover, the best PAHdegraders were screened out using plate assays and confirmed throughHigh Performance Liquid Chromatography (HPLC) analysis. Further, their enzymatic activities during the PAHs degradation were analyzed. As per the microscopic observations, the highest fungal distribution was in the upper epidermis of the leaves followed by the fungal distribution in the interspaces of palisade mesophyll layers. Out of isolated fungal species, two Penicillium spp. (Penicillium citrinum P23B-91 and Penicillium griseofulvum P9B - 30) showed the highest PAHs (phenanthrene, anthracene, naphthalene, and pyrene) degradation capabilities. Manganese peroxidase (MnP) enzyme dominated phenanthrene degradation in P. griseofulvum P9B - 30, which showed the highest phenanthrene degradation ability (61%). In addition, P. citrinum P23B-91 was good at degrading anthracene (88%) and also displayed a higher MnP activity during the anthracene degradation than laccase and lignin peroxidase activities. The discoveries from the toxicity assay during the PAHs degradation processes revealed that the produced byproducts had no toxic effects on the fungal growth cycle and the phyllosphere. Therefore this phyllosphere Penicillium spp. are ideal for the bioremediation of polluted air in urbanized areas.
Detection of earnings manipulation; evidence From Sri Lanka
(International Journal of Accounting & Business Finance, 2022) Wijesinghe, M.R.P.; Perera, W.T.N.M.; Yashodha, K.A.D.H.
Stream of literature on earnings management highlighted managers' opportunistic behavior to manipulate financial information with the view of extracting numerous unethical benefits. The purpose of this study is to investigate whether earnings manipulation exists in Sri Lanka as fabricating earnings which adversely triggers to the economy as a whole. We utilized Beneish model in our study as this model is a widely accepted, successful and important fraud sensitive indicator in detecting earnings manipulation under specific accruals method. As the sample, we considered twenty listed firms from Colombo Stock Exchange (CSE) for the period of 2013 to 2017 on quarterly basis. Days Receivable Index (DSRI), Gross Margin Index (GMI), Asset Quality Index (AQI), Sales Growth Index (SGI), Depreciation Index (DEPI), Sales General and Admin Expense Index (SGAI), Leverage Index (LVGI) and Total Accruals to Total Asset Index (TATA) were used to calculate the M-Score of the model which determines the susceptible companies where earnings manipulation could exist. Results, reveals that earnings manipulation exists in the entities listed on CSE at different degrees based on financial structure of such companies operating in different sectors. Our findings facilitate regulatory authorities to enhance effectiveness of standard-setting and monitoring to eliminate dodges where earnings could be manipulated. In addition, the study contributes to the knowledge base of academics and policymakers to make effective economic decisions.
Dip treatment of Aloe vera gel and Aloe vera in combination with cinnamon essential oils on stem-end rot of mango cv. ‘Karthakolomban’
(2022) Karunarathna, N. S. N.; Abeywickrama, K.; Kodituwakku, T. D.
This study was conducted to investigate the applicability of Aloe vera gel alone and mixed with cinnamon leaf and bark oil in controlling stem-end rot (SER) and extending the shelf life of mango cv. ‘Karthakolomban’. Mangoes were subjected to dip treatments of Aloe vera gel and Aloe vera gel in combination with cinnamon bark oil (2.0 μL/mL) and cinnamon leaf oil (2.0 μL/mL) and their pathological, physicochemical, sensory properties, and percentage shriveling were evaluated after a 10 d storage period at 12-14℃. Dip treatment of Aloe vera gel + cinnamon oils and Aloe vera gel reduced SER by 3.0 - 6.0%. Physicochemical and sensory properties did not show drastic alterations among all treatments and controls. Mangoes subjected to Aloe vera gel + cinnamon oil treatments demonstrated 0% shriveling. Uncoated fruits showed the highest shriveling. The findings highlight that Aloe vera gel may have a better prospect in the preservation and quality maintenance of mango in combination with cinnamon oils.
Effect of pre-treatments with natural compounds for controlling anthracnose in papaya variety Red Lady
(Journal of Horticulture and Postharvest Research, 2023) Kahawattage, A.; Hansini, N.; Daranagama, D.; Ranasinghe, C.
Purpose: Papaya (Carica papaya L.) is an economically important fruit crop affected by anthracnose caused by Colletotrichum gloeosporioides. The study was carried out to test two essential oils; Citronella oil and Cinnamon oil and two leaf extracts; Lantana camara and Ocimum tenuiflorum on four occasions of fruit development as pre-treatment assay in the field condition. Research Method: Essential oils were prepared as an emulsifier and leaf saps were extracted from dried leaves and both were set to 10% concentration. The experiment was conducted in a two-factor factorial experiment with Randomized Complete Block Design. Five treatments including the control were applied for four blocks representing stages of fruit development. Disease severity (0–5 scale) and disease severity index were calculated and statistically analyzed using ANOVA, MINITAB and Tukey’s pairwise analysis. Findings: According to the obtained results, four occasions of application of the selected treatment were highly significant with a minimum level of DSI (34.67 ± 4.62). L. camera leaf extract was highly effective as a pre-treatment with the least values for disease severity percentages (5.78 ± 0.43), disease severity score (0.3 ± 0.17) and disease severity index (26.67 ± 6.36). Research limitations: Flower bud initiation was delayed than the date expected due to the unpredicted heavy rainy condition. Originality/Value: The most effective block treatment interaction was shown on three occasions of application of L. camera leaf extract. This study facilitated the development of the most promising pre-harvest management strategy to control anthracnose disease which causes by the fungal pathogen C. gloeosporioides.
Effect of Trichoderma virens on vegetative and reproductive growth of Capsicum annuum cv. MI2 (green chilli)
(International Conference on Applied and Pure Sciences, 2020 Faculty of Science, University of Kelaniya, Sri Lanka, 2020) Sakalasooriya, S. M. C. P.; Kannangara, B. T. S. D. P.; Jayasekara, L. R.
Plant Growth Promoting Fungi (PGPF) facilitate a favorable interaction with plants in the rhizosphere through several biological processes. PGPF play a significant role in phytostimulation, phytoremediation and biofertilization. The use of PGPF as a biofertilizer has steadily increased in sustainable agriculture to reduce the use of chemical fertilizers. The objective of the present study is to investigate the effect of Trichoderma virens on vegetative and reproductive growth of Capsicum annuum cv. MI2 (green chilli). The trials were conducted in a greenhouse in the botanical garden, University of Kelaniya. Six weeks-old seedlings of C. annuum cv. MI2 were transplanted in solarized potting medium prepared by mixing topsoil and compost (3:1), filled into grow bags. Four treatments (103, 105, 107 conidia/ mL) including control (treated with Urea, Triple superphostphate and Muriate of Potash) were carried out along with five replications. Potting medium was inoculated with the conidial suspensions at the time of transplanting, followed by four inoculations until the time of uprooting. At the completion of 10 weeks after transplanting, the plants were uprooted, measured and represented as a percentage increment compared to the control; for the vegetative (shoot height, number of leaves, leaf area, average leaf length, girth of tap root, total leaf chlorophyll, fresh and dry weights of shoot and root mass) and reproductive parameters (number of buds, flowers and pods) of C. annuum cv. MI2. The plants treated with 107 conidia of T. virens per mL showed a significant increase in growth parameters of shoot height (18.55%), leaf number (79.78%), fresh weight of shoot (122.4%), fresh weight of root (14.17 %) and a significant increase in reproductive parameters of, number of buds (18.18%), and number of pods (143.75%) compared to the control was observed. Moreover, the plants treated with 105 conidia of T. virens per mL showed a significant enhancement in the growth parameters, leaf area (17.63%), total chlorophyll content (8.87%) and dry weight of root (54.16%) compared to the control. Present study clearly indicated that C. annuum cv. MI2 show better vegetative, as well as reproductive growth performance, when treated with conidial suspensions of T. virens. Therefore, T. virens can be suggested as a potential biofertilizer for C. annuum cv. MI2.
Effectiveness of protected areas in preventing rubber expansion and deforestation in Xishuangbanna, Southwest China
(Land Degradation & Development, 2018) Sarathchandra, C.; Dossa, G.G.; Ranjitkar, N.B.; Chen, H.; Deli, Z.; Ranjitkar, S.; De Silva, K.H.W.L.; Wickramasinghe, S.; Xu, J.; Harrison, R.D.
Protected areas (PAs) are supposedly key refuges for the world's remaining biodiversity. Our study site, Xishuangbanna, harbors a high proportion of China's biodiversity but is threatened by rapid deforestation and expansion of monoculture rubber. We quantified the success of Xishuangbanna's PAs in preventing deforestation.Most previous analyses of PA effectiveness have insufficiently accounted for biases arising from PA location and establishment, because they overlooked the importance of site‐matching in accounting for landscape change.We used matching methods to minimize such biases in comparing land use conversion rates inside and outside‐PAs. By 2010, Xishuangbanna had 3,455.5 km2 (~18%) designated as PAs. However, rubber occupied 22% of its land area and was expanding at a rate of 153.4 km2/year. Between 1988 and 2010, conventional analysis showed a deforestation rate of 9.3 km2/year. However, matching analysis showed a significantly higher rate of deforestation, 10.7 km2/year, which resulted in the deforestation of ~11% of PA's land. We argue that PAs were less effective than had previously been thought. The situation worsened from 2002 to 2010, when the deforestation rate within PAs was actually higher than that of outside PAs, although this difference was not significant. The designated higher levels of protection in ‘core’ zones were also unsuccessful in preventing deforestation. At current rates, within the next 50 years, a further 16% of PAs would be deforested in Xishuangbanna. This could even be an underestimate, as without intervention, drivers of deforestation tend to accelerate. Therefore, reviewing and strengthening current PA management policies is essential.
Effects of foliar and soil-applied liquid organic fertilizers on the growth of Basella alba L. and Centella asiatica L.
(The Journal of Agricultural Sciences - Sri Lanka, 2021) Ranasinghe, R.H.A.A.,; Ratnayake, R.M.C.S.; Kannangara, B.T.S.D.P.
Purpose: Environmental-friendly organic fertilizers reduce the adverse impacts of chemical fertilizers. This study was conducted to formulate organic liquid fertilizers using selected plant materials i.e., Tithonia diversifolia, Mikania scandens, Chromolaena odorata and Gliricidia sepium with selected organic wastes to compare the efficacies of foliar and soil-applications over the growth of leafy vegetables; Basella alba and Centella asiatica. Research Method: Selected plant materials were allowed to decompose for two months and thereafter fish waste was hydrolyzed separately with fruit wastes of Carica papaya, Ananas comosus and (1:1 w/w) mixture of both were mixed and nutrients analyzed. Fertilizers were foliar and soil-applied separately on C. asiatica and B. alba in RCBD in pot trials. Findings: Fertilizer formulated with decomposed plants + fish waste hydrolyzed with C. papaya significantly recorded the highest N (0.57%), P (0.06%) and highest growth of C. asiatica and B. alba over both soil and foliar applications followed by the fertilizer formulated with decomposed plants + fish waste hydrolyzed with C. papaya + A. comosus. Foliar-application of B. alba significantly showed the highest growth than the soil-application [shoot height (36.6±3.4 cm vs 30.0±1.5 cm), number of leaves per plant (21.7±1.4 vs 17.5±0.8) and plant fresh-weight (61.5±1.8 vs 55.6±0.9 g)] whereas, C. asiatica indicated no significant difference considering both fertilizer application methods. Research limitation: Pot experiments were carried out to provide uniform soil conditions for the experiment which was the main limitation compared to field trials. Originality/value: The formulated novel fertilizers could be utilized effectively in organic farming for safe and healthy leafy vegetables which reduce the adverse impacts of chemical fertilizers.