Thumbnail Image

Thesis

Browse

20212
Reset filters
Subject: Chemistry × Author: Jasleen Kaur × Start date: 2018 × Type: Thesis ×
Reset filters

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    ThesisItemRestricted
    Characterization and evaluation of rice straw lignin phenolics on pollen germination in pumpkin
    (Punjab Agricultural University, Ludhiana, 2021) Jasleen Kaur; Ramandeep Kaur
    Rice straw is one of the most abundant, renewable, cost-effective and non-edible agricultural feedstocks. Its burning has led to air pollution, loss of soil fertility and nutrient depletion, therefore valorization of rice straw is important. Straw was found to be chemically composed of 24% hemicellulose, 41% cellulose, 9% lignin, 20% extractives and 6% ash (silica). Lignin was extracted using dilute acid pretreatment (1% H2SO4) followed by alkaline hydrolysis using NaOH. FT-IR, 1H and 13C NMR were used for structural characterization of the lignin obtained from rice straw. The ethyl acetate extract of acid solubilized lignin was found to contain p-coumaric acid, ferulic acid and caffeic acid as the major phenolic acids which were isolated using preparative thin layer chromatography. The phenolic acids were characterized using elemental analyses, FT-IR, 1H and 13C NMR spectroscopy. Amides of p-coumaric acid, ferulic acid and caffeic acid were synthesized by their reaction with propyl and butyl amines using microwave irradiation and analysed using spectral studies. Phenolic acids and their amides were evaluated for their effect on pollen germination and tube growth in pumpkin. It was concluded that at 5 ppm concentration, germination percentage and pollen tube growth of p-coumaric acid, caffeic acid and their amides was enhanced than the control. These results could be utilised in increasing pollen tube length of Cucurbita moschata while making interspecific cross between C. moschata and C. pepo in order to transfer the hull-less and disease and virus resistant character of C. moschata to C. pepo.
  • Thumbnail Image
    ThesisItemRestricted
    Dissipation kinetics of halosulfuron-methyl and its effect on soil enzymes
    (Punjab Agricultural University, Ludhiana, 2021) Jasleen Kaur; Pervinder Kaur
    The present study investigate the degradation dynamics of halosulfuron-methyl in soils under laboratory conditions. Soil samples were treated with halosulfuron-methyl at application rates of 67.5, 135, 202.5 and 270 g ha-1. Soil type, application rate and temperature had a great influence on degradation rate of halosulfuron-methyl. Halosulfuron-methyl residues were extracted by ultrasonic assisted extraction (UAE) and matrix solid phase dispersion (MSPD) and quantified using HPLC-UV. The mean percentage recoveries obtained using UAE and MSPD varied from 88.33±5.44 to 99.43±4.22% and 85.70±4.98 to 97.37±3.50% with limit of detection (LOD) and limit of quantification (LOQ) as 0.0026 µg mL-1 and 0.008 µg mL-1, respectively. Dissipation of halosulfuron-methyl followed first order kinetics with half- lives varying from 9.38 to 33.77 days. Degradation increased with increase in temperature and varied from 14.39 to 33.77, 11.05 to 28.94 and 9.38 to 25.41 days at 5±2, 15±2 and 25±2°C. Halosulfuron-methyl had a transitory effect on dehydrogenase, alkaline phosphatase, acid phosphatase activity and soil microbial biomass (bacteria, fungi, actinomycetes and phosphate solubilizing bacteria population) but urease activity remains unaffected.