79 research outputs found
Characterization of Physiological and Biochemical Attributes of Neem (<i>Azadirachta indica</i> A. Juss) under Salinity Stress
No full textSalinity poses a significant threat to agricultural productivity worldwide, with its detrimental effects on plant growth and physiological processes. Understanding the mechanisms by which plants respond to salt stress is crucial for developing strategies to mitigate its impact on crop yield and sustainability. To address this issue, a pot study was conducted to determine the effect of salt stress on the physiological and biochemical attributes of neem (Azdiarchta indica A. Juss). Plants were grown for 10 months in pots filled with soil having different salinity levels of 3, 6, 9, 12, 15, and 18 dS m−1 and compared with a control of 1.7 dS m−1. The results showed that plant growth and chlorophyll contents declined as salinity levels increased. Due to oxidative stress, the contents of H2O2 increased under higher salt levels. The mitigation of oxidative stress was achieved through the activation of antioxidant enzymes (catalase, ascorbate peroxidase, peroxidase, and superoxide dismutase). Multivariate analysis indicated that Na+ accumulation in plants was positively related to H2O2 production and enzymatic activities, and negatively related to plant biomass, chlorophyll contents, root and shoot K+ concentration, and root K+/Na+. The experimental results suggest that neem plants can be grown in moderate saline soils
Postharvest control of anthracnose lesions and its causative agent, Colletotrichum musae by some oils
No full textAnthracnose of banana is incited by Colletotrichum musae. It is recognized as one the most destructive diseases of mature and immature banana fruits, resulting in huge economic losses all over the world. Present research deals with screening some oils both in vitro and in vivo for their antifungal activity against C.musae. Clove oil (0.1µl/ml) completely arrested the conidial germination and mycelial growth of C. musae. Fenugreek and almond oil exhibited significant inhibition of mycelial growth, 61% and 57% at a concentration of 2µl/ml. However, olive oil was least inhibitory on the test fungi. Clove oil also a showed marked reduction in anthracnose lesions on banana fruits, thereby suggesting disease control. Scanning electron microscopy revealed severely damaged mycelium and conidia. FTIR studies show the presence of important bands representing phenols, terpenes, aldehydes, and ketones. Based on our findings; clove, fenugreek and almond oil demonstrated fungicidal and fungistatic activities against anthracnose pathogen. Hence, these oils can be considered as potential alternatives to chemical treatments.</jats:p
Optimizing callogenesis in five potential medicinal herbs for the bioactive constituents: a sustainable approach to pharmaceutical production
No full textThe search for natural antioxidants to safeguard against several diseases is expanding rapidly. Interestingly, the levels of antioxidants have been discovered to be greater in the in vitro-raised calli than the plant extracts in vivo. The aim of this research was to standardize the protocols for culturing calli of five potential medicinal herbs and determine their antioxidant and polyphenolic compounds. The calli of carnation, goji berry, harmal, bitter cucumber, and datura were developed from young leaves using Murashige and Skoog media with varied forms and concentrations of cytokinin and auxin in combination after their optimization. Goji berry, carnation, and datura initiated callus in 13 days, faster than bitter cucumber (20 days). Datura had a 28.7% higher callus induction rate than bitter cucumber. The callus weight of goji berry was three times higher than harmal, with a 25.4% greater diameter than bitter cucumber. The callus of goji berry had 4.3 times more phenolic and ascorbic content than datura and 1.9x more than harmal. The callus of datura had twice the total antioxidant capacity of harmal. The callus of goji berry exhibited 5.7% increased radical-scavenging activities than datura. The enzyme activities of catalase and superoxide dismutase were 2.6% and 2.4% greater in the callus of goji berry than datura. The callus of goji berry also had 2.1% and 2.4% increased peroxidase and ascorbate peroxidase activities than datura and bitter cucumber, respectively. From the findings, it can be concluded that the callus of goji berry is a highly promising source of natural antioxidants, exhibiting significantly higher levels of antioxidant and polyphenolic compounds compared to other medicinal herbs
Exogenous melatonin mitigates the adverse effects of drought stress in strawberry by upregulating the antioxidant defense system
No full textStrawberry (Fragaria pound ananassa Duch.) is one of the most popular fruits in the world. Environmental stresses have a significant impact on the strawberry's growth and development. The most significant environmental stressor is drought, which has a negative effect on strawberry's production. This present research aimed to examine the protective role of melatonin (MT, 100 mM) on strawberry plants subjected to drought stress. The current results showed that drought stress signifcantly decreased growth, gas exchange parameters, and photosynthetic pigments content in strawberry. In contrast, MT application remarkably improved strawberry growth, gas exchange elements, and pigments concentration in strawberry leaves under drought stress. In addition, MT supplementation significantly reduced the levels of malondialdehyde (MDA), hydrogen peroxide (H2O2) and electrolyte leakage (EL). Further, MT pretreated strawberry plants effectively increased the antioxidant enzyme [Ascorbate peroxidase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX)] activity and non-enzymatic antioxidant [Ascorbate (AsA) and glutathione (GSH)] activity when the plants were exposed to drought stress. In conclusion, our results suggested MT application significantly improved soluble sugar accumulation, and photosynthetic apparatus, which may reduce oxidative stress biomarkers production. Finally, MT application increased the drought stress tolerance of strawberry seedlings.(c) 2023 SAAB. Published by Elsevier B.V. All rights reserved.King Saud University, Riyadh, Saudi Arabia [RSPD2023R1048]The authors extend their appreciation to the Researchers Supporting Project number (RSPD2023R1048) , King Saud University, Riyadh, Saudi Arabia
Synthesization, Characterization and Application of Nano-Particles Ferric Oxide in Sodium Sulfide Oxidation
Get PDFSulfides usually found in the wastewater produced by chemical and petrochemical
industries such as tanneries, refineries, polymer industries. Removing sulfides from the
wastewater is currently a big challenge to the industries because sulfides are soluble in
water and various research and technologies have been studied and developed in order to
remove sulfides content. In this project, the author is focusing on removing sulfides
through oxidation process by using hydrogen peroxide as an oxidizing agent with the
presence of nano-particles ferric oxide as a catalyst. Nano-materials are increasingly
gaining the attention of the scientific community and also public due to their various
applications in the industries for example as a catalyst. In this project, author will
developed the procedure in preparing ferric oxide nano-particle as a catalyst and the
application of it in sodium sulfide oxidation process. Basically three stages are involved,
the synthesization, characterization and application. In application stage, the author will
study two parameters of the oxidation rate that is catalyst loading and sulfide
concentration. The effect of these parameters will be study by varying the variables for
these parameters. The results shows that after the more catalyst added, the oxidation
process increase by time and removal of sulfide can be achieve faster. The objectives
for this project are to successfully produce nano-particle ferric oxide as catalyst and to
apply it in the sulfide oxidation process.
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Chemical Composition, FTIR Studies and Antibacterial Activity of Passiflora edulis f. edulis (Fruit)
No full textBecause of the strong interest in the use of bio-products as alternatives to chemically derived antibiotics or antimicrobial agents, passion fruits extracts were evaluated for their antibacterial activity and chemical composition. Various solvent extracts of P. edulis were screened for their antibacterial activity by Agar well diffusion technique against an array of pathogenic bacteria (Gram positive and negative). Macro dilution technique was used to determine the Minimum inhibitory concentration of the potent extracts. Bacterial strain showing significant inhibition was further subjected to scanning electron microcopy (SEM) and the morphological changes induced by extracts were noted. Chemical composition of extracts showing strong antibacterial activity was determined by GC-MS and FTIR analysis. Extracts of Passion fruit (pulp with seeds) show significant inhibitory effects against test isolates but in a variable manner. Amongst all the test isolates Bacillus subtilis showed maximum inhibition followed by E. coli and P. aeruginosa. Ethyl acetate extracts had the least activity against the tested microorganisms. Gas chromatography-mass spectrometry of ethanol extracts showed the presence of important chemicals, such as Tetracosamethyl-cyclododecasiloxane; Dodecanoic acid, 10-methyl-, methyl ester cyclosiloxane, hexadecamethyl; 3-isopropoxy-1,1,1,7,7,7-hexamethyl-3,5,5-tris (trimethylsiloxy)tetrasil; 9-hexadecenoic acid, 9-octadecenyl ester, (Z,Z)- Fourier transform infrared studies revealed important functional groups which included phenols, esters, flavonoids, aromatic compounds, and alcohols. Significant antibacterial activity of the extracts could be attributed to phenolic compounds, esters and other chemical components identified in ethanolic extracts. Scanning electron micrographs of B. subtilis treated with ethanol extracts showed distorted shapes, rough and corrugated cell margins, and aggregations of cells. Our data depict the significant antimicrobial activity of extracts against Gram positive bacteria while the Gram negative bacteria exhibited weak inhibition by all the extracts. Based on our findings, passion fruits can be used in preparations of antimicrobial formulations against Gram positive microorganisms especially B. subtilis
The formation and enactment of teacher expectations of student achievement in private schooling
No full textThis thesis was scanned from the print manuscript for digital preservation and is copyright the author.
Researchers can access this thesis by asking their local university, institution or public library to
make a request on their behalf. Monash staff and postgraduate students can use the link in the References field
Building a road to nuclear disarmament bridging the gap between competing approaches
No full textIntroduction -- Nuclear disarmament: Tracing lessons from history -- Competing approaches: Identifying the gaps -- Contemporary security environment, new technologies and nuclear disarmament -- Bridging the gap: Creating a new security environment for nuclear disarmament -- Conclusion"This book focuses on comprehending the contemporary global security environment, creating a new roadmap for nuclear disarmament by creating a balance between deterrence supporters and disarmament advocators. The author identifies the divide between competing approaches such as traditional security-centric aspects and humanity-centered disarmament perspectives, tackling the complex question of how to balance some states' requirements for effective nuclear deterrence with other states' long-term desire for a nuclear-free world. The book explores how new technologies such as cyber and AI advances are available to more countries than nuclear technology, and could level the playing field for weaker nuclear weapons states. It also looks into the issues which continue to be obstacles in the way of convincing the nuclear weapon states (NWS) on nuclear disarmament. The author argues that the gap between deterrence supporters and disarmament advocators can be filled by creating a new environment for renewed consensus on achieving a world free of nuclear weapons. This book provides a deeper understanding and critical analysis of how global evolving parallel traditional security and normative trends relating to nuclear weapons can be bridged in order to make the disarmament debate practically achievable. This volume will be of great interest to students and scholars, researchers, policy makers, NGOs and members of the diplomatic community, in the fields of security studies, strategic studies and nuclear polic
TiO2 nanoparticles: Green synthesis and their role in lessening the damage of Colletotrichum graminicola in sorghum
No full textFungal pathogens pose a persistent threat to crop plants, risking global food security. Anthracnose of sorghum caused by Colletotrichum graminicola causes a considerable loss in sorghum production. This study aimed to manage the anthracnose disease in sorghum using green-synthesized TiO2 nanoparticles using pomegranate peel and to assess their impacts on the agroeconomic attributes of sorghum. Synthesized TiO2 nanoparticles showed strong dose-dependent antifungal activity against C. graminicola and significantly reduced mycelial radial growth, comparable to commercial fungicides. Foliar application of TiO2 at concentrations of 150 and 200 ppm reduced the disease index >60% in pot trials. Additionally, the effect of TiO2 NPs on the growth and yield of sorghum plants and the possible mechanism(s) behind the suppression of anthracnose disease were deciphered. TiO2 NPs also improved shoot and root length, biomass accumulation, penile size, number of grains, and grain weight in sorghum plants infected with C. graminicola. Application of TiO2 NPs significantly increased the content of defense-related biochemicals, including total phenolic contents, activities of defense-related enzymes (PO, PPO, and PAL), photosynthetic pigments (total chlorophyll contents and carotenoids), and total protein contents. Collectively, our study verified the potential of green-synthesized titanium dioxide nanoparticles to suppress anthracnose disease by activating a defense system and stimulating growth and yield promotion under pathogen stress
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