Loading...
Thesis
Browse
Search Results
ThesisItem Open Access Dissipation kinetics of imazethapyr and its effect on soil enzymes(Punjab Agricultural University, Ludhiana, 2020) Lovedeep Kaur; Pervinder KaurFate of herbicide in soil is greatly affected by several factors viz. soil properties, temperature, and application rate. The present study assesses the degradation dynamics of imazethapyr in soils of Punjab under laboratory conditions. The dissipation of imazethapyr followed biphasic first order kinetics and soil type, application rate and temperature greatly influenced the dissipation behavior of imazethapyr. The half-life of imazethapyr for the first relatively faster phase was 5.87 to 7.47 days and it ranged from 76.50 to138.68 days in second relatively slower phase in studied soils. The adsorptive potential was probably responsible for the difference in dissipation rate between the studied soils. Degradation rate of imazethapyr increased with temperature and its half life ranged from 76.50 to138.68, 79.44 to 142.92 and 83.31 to 145.09 days at 25, 35 and 45°C. The presence of imazethapyr metabolites was also detected in studied soils using LC-MS/MS. Imazethapyr get degraded into three metabolites which ultimately get mineralized to carbon dioxide as end product. Variation in physicochemical properties of soils and applied herbicide changed the period of appearance and persistence of the metabolites. Imazethapyr application has short lived as well as transitory effect on dehydrogenase activity (DHA), alkaline phosphates activity (APA) and soil microbial biomass at all application levels but urease activity remains unaffected.ThesisItem Restricted Production of modified xylans and xylooligosaccharides for valorization of rice straw(Punjab Agricultural University, Ludhiana, 2020) Puneet Kaur; Ramandeep KaurThe present study attempts to valorise rice straw, one of the most abundant, renewable, economic and environment-friendly agricultural wastes, by the production of modified xylans and xylooligosaccharides (XOS). The chemical composition of rice straw was determined using detergent system method and the percent contents of extractives, cellulose, hemicellulose, lignin and ash (silica) were found to be 20, 41, 24, 9 and 6, respectively. Alkaline extraction procedure employed for extracting hemicellulose was optimized using central composite design of response surface methodology such that maximum yield of hemicellulosic xylan (19.97%) was obtained by carrying out reaction with 11.04% (w/v) NaOH for 3.126 hrs at 80.146 . Hemicellulosic xylan was structurally characterized by FT-IR and NMR spectroscopic studies and subjected to chemical modifications i.e. acetylation, benzylation and carboxymethylation followed by their spectral analysis. Total antioxidant capacity of xylan and modified xylans was evaluated by phosphomolybdenum method using ascorbic acid as standard. Although the ascorbic acid equivalent (AAE) value of xylan was higher than modified products but higher thermal stability of modified xylans may account for their suitability in formation of packaging films. Autohydrolysis of xylan was carried out with dilute sulphuric acid (0.1, 0.25, 0.5 and 1.0M) at 121oC, 15 psi for 10 min to obtain XOS-rich autohydrolysates which were qualitatively analysed using thin layer chromatography. These autohydrolysates were found to exhibit significant concentration dependent antioxidant activity and higher prebiotic potential for growth of Lactobacillus rhamnosus and Lactobacillus casei than established prebiotic fructooligosaccharides.ThesisItem Restricted Derivatization of benzimidazole and their evaluation as antinematic agents(Punjab Agricultural University, Ludhiana, 2020) Lovepreet Kaur; Utreja, Divya2-Substituted benzimidazole derivatives were synthesized by condensation reaction of ophenylenediamine with different aryl aldehyde. N-alkylation of substituted derivatives was carried out by using different alkyl halides in the presence of phase transfer catalyst tetrabutyl ammonium hydrogen sulfate and 30% KOH as base. Characterization of synthesized derivatives was carried out using 1H NMR, 13C NMR and IR spectroscopy. The resulted compounds were also screened for their nematicidal activity against root knot nematode Meloidogyne incognita by egg hatching and mortality test. All the compounds exhibited significant nematicidal potential as compared to control. Maximum egg hatching inhibition potential and maximum mortality potential was exhibited by compound 2-(2-nitrophenyl)1H-benzimidazole (3a).ThesisItem Open Access Hydrogen peroxide and glucose sensing using Magnesium ferrite nanoparticles as peroxidase mimics(Punjab Agricultural University, Ludhiana-, 2020) Ekjot Singh; Manpreet KaurNatural enzymes have been used in the food industry, biosensing and pharmaceuticals because of their high catalytic activity. However, they have some inherent drawbacks as their catalytic activity is affected by environmental conditions such as pH, temperature and inhibitors which lead to their denaturation and thus increasing operation cost. Study pertaining to materials showing properties similar to enzymes is a thrust area of research. Magnesium ferrite (MgFe2O4) NPs have gained focus of researchers because of their good catalytic activity, stability and magnetic properties. Enhanced catalytic activity can be obtained by surface coating by suitable surfactant. In this work, CTAB (cetyl trimethyl ammonium bromide) coated MgFe2O4 NPs were prepared. MgFe2O4 NPs were synthesized using sol-gel methodology and CTAB@MgFe2O4 by sonicating the CTAB with NPs in different w/w ratios. The XRD pattern of MgFe2O4 NPs confirmed single-phase formation of spinel structure with cubic symmetry. FT-IR studies confirmed presence of CTAB. Surface area, Particle size and magnetic character of the NPs were evaluated by BET, TEM and VSM respectively. CTAB@MgFe2O4 (1:1) showed best peroxidase like activity towards odianisidne dihydrochloride and was affected by solution pH, temperature and substrate concentration. Under optimal conditions, the as synthesized CTAB@MgFe2O4 (1:1) based system could be used for colorimetric detection of H2O2 in the linear range of 20-300 µM with a detection limit of 10 µM. Moreover, this system could also be used for the detection for glucose in the range of 10-1000 µM with a detection limit of 5 µM.ThesisItem Restricted Magnesium ferrite and Graphene quantum dots nanocomposite for catalytic application(Punjab Agricultural University, Ludhiana, 2020) Pandey, KomalHerein, a novel strategy has been proposed to fabricate graphene quantum dots (GQDs) deposited magnesium ferrite nanoparticles (MgFe2O4 NPs) nanocomposite for paranitrophenol (PNP) degradation and reduction activity. GQDs are deposited over MgFe2O4 through a cothermolysis method. The structural, morphological, and optical properties of the prepared MgFe2O4 – GQDs nanocomposite were characterized by analytical techniques such as X-ray diffraction, Fourier-transform infrared spectroscopy, transmission electron microscopy, Brunauer Emmit Teller (BET) surface area analysis, Vibrating sample magnetometer, and UV- visible spectrophotometry. The photodegradation and reduction capability of the nanocomposite has been demonstrated by comparison with MgFe2O4 NPs. The catalytic activities of the nanocomposite and MgFe2O4 were evaluated in terms of photodegradation and reduction of PNP in aqueous solution. The greater catalytic activity is attributed to the extended conjugation of GQDs along with the large photo-induced charge separation through the transfer of photo-generated electrons from MgFe2O4 to GQDs. The light upconversion properties of uniformly deposited graphene quantum dots could also be a reason for the higher visible light catalytic activity of the synthesized magnetically recoverable hybrid photocatalyst. Overall, the present approach adheres to green chemistry principles and the nanocomposite holds promise for the development of remarkably efficient catalytic systems.ThesisItem Restricted Magnesium ferrite and Graphene quantum dots nanocomposite for catalytic application(Punjab Agricultural University, Ludhiana, 2020) Pandey, Komal; Manpreet KaurHerein, a novel strategy has been proposed to fabricate graphene quantum dots (GQDs) deposited magnesium ferrite nanoparticles (MgFe2O4 NPs) nanocomposite for paranitrophenol (PNP) degradation and reduction activity. GQDs are deposited over MgFe2O4 through a cothermolysis method. The structural, morphological, and optical properties of the prepared MgFe2O4 – GQDs nanocomposite were characterized by analytical techniques such as X-ray diffraction, Fourier-transform infrared spectroscopy, transmission electron microscopy, Brunauer Emmit Teller (BET) surface area analysis, Vibrating sample magnetometer, and UV- visible spectrophotometry. The photodegradation and reduction capability of the nanocomposite has been demonstrated by comparison with MgFe2O4 NPs. The catalytic activities of the nanocomposite and MgFe2O4 were evaluated in terms of photodegradation and reduction of PNP in aqueous solution. The greater catalytic activity is attributed to the extended conjugation of GQDs along with the large photo-induced charge separation through the transfer of photo-generated electrons from MgFe2O4 to GQDs. The light upconversion properties of uniformly deposited graphene quantum dots could also be a reason for the higher visible light catalytic activity of the synthesized magnetically recoverable hybrid photocatalyst. Overall, the present approach adheres to green chemistry principles and the nanocomposite holds promise for the development of remarkably efficient catalytic systems.ThesisItem Open Access Synthesis of inorganic zinc analogues as antifungal agents against karnal bunt (Neovossia indica) of wheat(Punjab Agricultural University, Ludhiana-, 2020) Priambidha; AnjaliZinc carbonate nanoparticles of three different sizes were prepared in situvia sonochemical approach in aqueous media using different concentrations of zinc ions and carbonate ions used as precursor to achieve aqua formulated nano zinc carbonates (ZC-1 to 3). Complete topomorphological nano parameters were achieved by SEM, TEM, IR, XRD and UV characterization techniques. Prepared samples were screened for their in vitro antifungal potential against Neovossia indica, a seed borne fungal pathogen of wheat by both spore germination inhibition method and poisoned food technique. The results showed that the ED50 value calculated from inhibition of radial fungal growth in Petri plates gave the same corresponding results as depicted by spore germination inhibition method. The results revealed that nano ZC-1 to 3 exhibited better potential in inhibiting the germination of fungal spores, than bulk samples of ZnCO3 prepared by mixing of two precursors. All the three samples ZC-1 to ZC-3 inflicted the ED50≥200µg/ml, the concentration above this was not used for evaluation. This value was much higher than standard fungicide Oxathiin (ED50= 300µg/ml).ThesisItem Open Access Formation and characterization of Foeniculum vulgare oil nanoemulsion and it’s herbicidal potential(Punjab Agricultural University, Ludhiana, 2020) Gupta, Sonali; Pervinder KaurEssential oil (EO) based bioherbicides are topic of interest for the new era agriculture because of their sustainable use in the control of weeds. The present study aims to formulate an oil/water (O/W) nanoemulsion (NEm) of Foeniculum vulgare Mill. (fennel) EO and evaluate its herbicidal activity against Phalaris minor Retz. and Avena ludoviciana Durieu. Twenty-six compounds were detected in the GC-MS analysis of F. vulgare EO of which estragole (43.16%) and anethole (29.34%) were the major compounds. In the laboratory bioassay study, the EO concentration of 0.01, 0.02, 0.05, 0.1, 0.2, 0.3, 0.4 and 0.5 (wt%) significantly inhibited the germination and growth of weeds in dose dependent manner. IC50 value of P. minor and A. ludoviciana was found to be 0.12 and 0.03 (wt%), respectively. Two effective oil concentrations 0.05 and 0.1% (wt%) were formulated into NEms with tween 80 (0.5 wt%) and water. Transmission electron microscopy (TEM) and Z-average diameter data indicated the spherical nature of droplet and confirmed the formation of NEms with average size below 130 nm. Physicochemical properties of NEms indicated their O/W and isotropic nature. NEms were stable to storage, centrifugation and dilution. Formulated NEms completely inhibited the germination of P. minor and A. ludoviciana by adversely affecting the physiological processes like membrane leakage and reactive oxygen species (ROS) mediated cellular damage. The NEms of F. vulgare EO has herbicidal properties as it has high phytotoxic effect and interferes with germination, growth and physiological processes of weeds.ThesisItem Open Access Derivatization of triazines and their evaluation as antifungal agents(Punjab Agricultural University, Ludhiana, 2020) Kiranveer Kaur; Utreja, DivyaSeven mono-, di- and tri-substituted derivatives of s-triazine were synthesized by condensation reaction of s-triazine with different aromatic amines at different temperature conditions. The characterization of synthesized derivatives was done using 1H NMR, D2O exchange, 13C NMR and IR spectroscopy. Among all the synthesized triazine derivatives, 6-chloro-N2,N4-bis(4-bromophenyl)-1,3,5-triazin-2,4- diamine, N2, N4-bis(4-nitrophenyl)-N6-(2,4,6-trichlorophenyl)-1,3,5-triazin-2,4,6- triamine and 6-chloro-N2,N4-bis(4-nitrophenyl)-1,3,5-triazin-2,4-diamine were found to be most effective compound against Helminthosporium oryzae, Rhizoctonia solani and Alternaria brassicae, respectively with 100% mycelial growth inhibition where as compound 4,6-dichloro-N-(2,4-dinitrophenyl)-1,3,5-triazin-2-amine, triazine (1) was found to be least effective with ED50 value 188, 230 and 258 μg/ml.
