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ThesisItem Open Access Study on nitrogen metabolism under the influence of different planting dates in oat (Avena sativa L.)(Punjab Agricultural University, Ludhiana, 2020) Aanchaldeep Kaur; Goyal, MeenakshiThe current investigation was carried out to evaluate the effect of staggered planting dates (Oct 9, Oct 24, Nov 13, Nov 26, Dec 11 and Dec 26) and growth stages (40, 50 and 60 DAS) in oat through field experiment during Rabi season using two genotypes. The OL-10 is a fast growing genotype with high regeneration potential and OL-11 is relatively slow growing single cut variety. The activities of nitrate reductase and nitrite reductase were observed high during optimum (Oct 24) and sub-optimum (Oct 9 and Nov 13) planting dates but low during late planting dates (Nov 26, Dec 11 and Dec 26). The activities of glutamine synthetase, glutamate synthase, glutamate dehydrogenase, glutamate oxaloacetate transaminase and glutamate pyruvate transaminase were observed high during late planting dates but were stable or slightly low at optimum and sub-optimum ones. The optimum and sub-optimum planting dates were also characterized by higher total chlorophyll, dry matter (DM), ash, crude fat, acid detergent fibre (ADF) and neutral detergent fibre (NDF) content in comparison with late planting dates. Crude protein, non-protein crude protein, in vitro dry matter digestibility, nitrate-N, nitrite-N and free amino acids increased with delay in planting dates. Meanwhile, the quality attributes of the oat except DM, ADF, NDF and free amino acids got declined with advancing maturity of vegetative fractions of plant. Furthermore, yield and yield attributes got declined with delay in planting time. Overall, OL-10 had higher nitrogen assimilation potential, nutritive value and yield potential as compared to OL-11 genotype.ThesisItem Restricted Evaluation of biochemical properties of selected Indian vegetable oils and their blends(2020) Jassal, AditiThe present investigation was designed to formulate the healthy oil blends with balanced ω-6: ω-3 ratio and rich antioxidant profile. A total of 231 oil blends were formulated by mixing oils of five different oilseed crops viz., canola oilseed rape cv. GSC7, sunflower cv. PSH 1962, sesamum cv. Punjab Til No.2, Indian mustard cv. Giriraj, and groundnut cv. SG99 in different proportions. Of these 231 blends, 26 blends derived by mixing canola, sunflower and sesame were selected on the basis of (i) saturated fatty acid content less than 10%; (ii) ideal ω-6: ω-3 ratio (3.5-10:1) and (iii) proportion of oleic acid >50%. These selected blends were further evaluated for their antioxidative profile such as total phenols, DPPH-RSC and tocopherols which varied from 3.02-6.81 mg/100g, 59.63-62.10% and 63.81-71.76 mg/100g respectively. The chemical properties such as acid value, saponification value, iodine value, peroxide value, p-anisidine value and totox value of these blends ranged between 2.01-3.40 mg KOH/g, 182.93-190.4 mg KOH/g, 82.23-89.49 g I2/100g, 6.33-10.83 meq/kg, 1.12-2.41 and 14.29-23.74, respectively. A significant negative correlation was noticed between DPPHRSC and three oxidation indices such as peroxide, p-anisidine and totox value indicating that high value of RSC protects the oil from oxidation. Out of twenty-six oil blends, three blends of canola with sunflower and sesame (40:30:30, 30:30:40, 35:30:35) and three blends of canola with sesame (50:50, 40:60, 45:55) were shown to possess higher antioxidative profile. These six oil combinations also possessed lower oxidative indices and higher smoke point (241.30-244.77°C) indicating their suitability for frying purpose.ThesisItem Open Access Effect of plant growth promoting Rhizobacteria on germination, antioxidant enzymes and bulb quality in onion (Allium cepa)(Punjab Agricultural University, Ludhiana, 2020) Gaganjit KaurIn the present study, ten different PGPR treatments were given to the onion seeds (PRO-6 and ADR). In the first experiment, seeds were sown in the petri-dishes and then analysed for various parameters. The germination percentage (100%) was observed maximum in PRO-6 and ADR. After 7 DAG shoot length (0.53 cm) was same in both varieties and after 14 DAG, it showed maximum in PGPR 7 (2.87 cm) in PRO-6 and ADR (2.97 cm) in PGPR 3. In PRO-6, dry weight of roots and shoots was same 0.08 g and in ADR it was 0.08g in roots and 0.09g in shoots. For peroxidase, PGPR 7 showed maximum activity in roots (0.064-0.028 change in absorbance/min/g FW) in PRO-6 and ADR, respectively. In shoots, PGPR 3 showed maximum activities (0.033-0.14 A OD) in PRO-6 and ADR, respectively. PGPR 3 and PGPR 7 showed maximum activity for catalase in both roots and shoots of PRO-6 and ADR, respectively. PGPR 3 showed maximum activity for superoxide dismutase in both varieties while for ascorbate peroxidase, PGPR 7 showed maximum activity in PRO-6 and ADR. The antioxidant capacity in roots and shoots was observed to be (95.45% and 55.49%) for PRO-6 and (84.38 and 79.65%) for ADR, respectively. On the basis of first experiment, it was observed that the Bacillus cereus (PGPR 7) and Pseudomonas fluoroscens (PGPR 3) were the best plant growth promoters among all the treatments. So, in the second experiment, treatments of PGPR 3 and PGPR 7 were selected and seeds were sown in the field. Shoot length (13.4- 90.3 cm) in PRO-6 and ADR (17.6- 92.0 cm), no. of leaves (1.5-4.5) in PRO-6 and ADR (1.5-4.8) and yield per plot in PRO-6 (0.27 gm/m2) and ADR (0.32 gm/m2) were observed maximum in PGPR 7. The antioxidant enzymes: peroxidase, catalase and superoxide dismutase showed maximum activity in PGPR 7 in roots, leaves and bulb during different intervals of time (45, 90, 135 DAS and at maturity) in PRO-6 and ADR. Total phenol (52.79 and 57.87 mg/100g), anthocyanins (56.10 and 59.23 mg/100g), quercetin (4.6¬6.9 1.1g/100g), pyruvic acid (0.05- 0.07 mmol/g FW) and lachrymatory factor (0.66- 0.53 wnol/100g FW) were observed maximum in PGPR 7 of both PRO-6 and ADR. It was concluded that the treatment given with PGPR 7 led to higher activities of antioxidant enzymes and other biochemical parametersof onion (PRO-6 and ADR).ThesisItem Restricted Role of metal oxides / nanoparticles in improving growth and antioxidant status under heat stress in wheat (Triticum aestivum L.)(Punjab Agricultural University, Ludhiana, 2020) Thakur, Shivali; Asthir, BavitaThe present study was conducted to evaluate the growth, antioxidant potential, free radical scavenging and membrane stability parameters in root and shoot of two wheat (Triticum aestivam L.) genotypes (Unnat PBW 343 and HD 296) treated with 1.5ppm and 10 ppm ZnO and TiO2 nanoparticles (NP) under normal and high temperature (32oC) on the 12th day of germination. For characterization of ZnO NP, present study employed scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX) technique and the results demonstrated different shape and size of NPs such as bunch of irregular particles, round shaped and small particles. Physiological parameters, viz., shoot and root length, biomass, germination percentage and biochemical parameters such as activities of antioxidant enzymes, viz., catalase (CAT), superoxide dismutase (SOD), guaicol peroxidise (GPX) and natural antioxidants, viz., phenols and flavonols also increased with application of ZnO and TiO2 NPs in parallel with higher free radical scavenging as measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant potential (FRAP). Both ZnO and TiO2 NPs had promoting effect at lower concentration (1.5 ppm) compared with higher concentration (10 ppm). Though, TiO2NPs improved seedling performance slightly better than ZnO NPs, antioxidant defence response was higher with ZnO NPs. Nonetheless, compared to the HD 2961 cultivar, the Unnat PBW 343 cultivar had lower malondialdehyde (MDA), hydrogen peroxide (H2O2) contents and higher upregulation of antioxidative enzymes under heat stress conditions treated with NP owing to the better expression of antioxidants. Therefore, pretreatment by ZnO and TiO2NPs at 1.5 ppm, no doubt, improved resistance against heat stress substantially through increase in GPX and SOD activities, and thereby stabilizing membrane as evidenced by lower MDA and H2O2 content.ThesisItem Open Access Genetic variability for the efficiency of nitrogen metabolism among natural and derived Brassica rapa accessions(Punjab Agricultural University, Ludhiana, 2020) Goyal, Sakshi; Sharma, SanjulaThe present situation urgently demands the crop plants with increased nitrogen (N) uptake and assimilation efficiencies in order to reduce damage caused to the ecosystem due to nitrate leaching. With this objective, the variation and correlation of N uptake and assimilatory enzymes with non-enzymatic metabolites and yield parameters was studied at three developmental stages viz., pre-anthesis, anthesis and post-anthesis in a DArT-genotyped association panel of 195 Brassica rapa diversity set grown at a recommended dose of 100 kg N/ha. Among all the growth stages, N-metabolism enzymes were maximally active during anthesis stage. Correlation study depicted a significant positive relationship between all the N-metabolism enzymes and biochemical parameters. Out of 195 genotypes, seven promising genotypes viz., DRBS-56-A5, DRP-31-A5-P5, DRT-80-A5, DRT-59-A1, DRT-66-A2, LTE- 16 and CN107774 recorded highest enzyme activities and nitrogen use efficiency (NUE). Of these, DRT-59-A1, LTE-16, CN107774 and DRP-31-A5-P5 were higher yielding as well. The genome wide association study (GWAS) revealed 21 significant SNP’s associated with N metabolism traits on all the chromosome from A01-A10 except chromosome 4. SNPs that include A02_1906734 and A03_20450126 individually co-localized with two functional gene groups that were associated with QTLs for glutamate dehydrogenase, glutamine synthetase and glutamate synthase. The study helped in identification of genotypes with favorable combination of traits that could be of interest in Brassica breeding programs. Also, the identified significant SNPs on further validation could be used for marker assisted selection and trait introgression in Brassica for raising N uptake and assimilation rates.ThesisItem Open Access Enhancing carbohydrate and starch accumulation in microalgae for bioethanol production(Punjab Agricultural University, Ludhiana, 2019) Amanpreet Kaur; Taggar, Monica SachdevaThe present study was carried out to optimize the culture conditions for enhancing carbohydrate and starch accumulation in Chlorella sorokiniana for the bioethanol production. The growth and biomass of microalgae was studied with the sparging of carbon dioxide into the culture medium. The mean growth (0.70), fresh biomass (7983.33 mg l-1), dry biomass (1516.67 mg l-1) and biomass productivity (163.33 mg l-1 day-1) of microalgae was higher with the sparging of carbon dioxide into the culture medium. The effect of different concentrations of potassium nitrate, i.e. 4, 2 and 1 g l-1 in the culture medium revealed high growth (0.98), fresh (8053.33 mg l-1) and dry biomass (1556.67 mg l-1) of microalgae at 4 g l-1 potassium nitrate in the culture medium. The maximum accumulation of total carbohydrate (50.28%) and starch (34.06%) in the microalgae was observed at 1 g l-1 potassium nitrate concentration in the culture medium at 2 days after culturing (DAC) while the total soluble protein content (18.24%) was observed to be maximum at 4 g l-1 potassium nitrate concentration in the culture medium at 8 DAC. The maximum chlorophyll a, b and total chlorophyll content of 403.22 μg g-1 fw, 346.66 μg g-1 fw and 749.88 μg g-1 fw of microalgae was observed at 4 g l-1 potassium nitrate level in the culture medium, respectively. Morphological characterization of C. sorokiniana revealed dense starch granules in the cells under nitrogen limiting conditions. Chitosan, at a concentration of 200 ppm, showed maximum flocculation (90.94%) of microalgal suspension after 60 min. Pre-treatment of microalgal biomass with 1 N sulphuric acid revealed maximum production of total (487.41 mg g-1) and reducing sugars (277.56 mg g-1). The fermentation of microalgal hydrolysate by Saccharomyces cerevisiae resulted in maximum ethanol content and yield of 0.52 g and 0.052 g g-1 biomass at 96 h of fermentation.ThesisItem Restricted Evaluation of magnetic nanoparticle immobilized cellulases for enzymatic saccharification of rice straw(Punjab Agricultural University, Ludhiana, 2019) Prabhpreet Kaur; Taggar, Monica SachdevaThe present study was conducted to evaluate the efficiency of magnetic nanoparticle immobilized cellulases for enzymatic saccharification of rice straw. The optimization studies for cellulase production by A. fumigatus under solid state fermentation conditions revealed that the maximum cellulase production (filter paper activity of 486.09 nmol min-1g-1ds, CMCase activity of 2482.33 nmol min-1g-1ds, cellobiase activity of 1911.13 nmol min-1g-1ds and xylanase activity of 8.90 μmol min-1g-1ds) was recorded with mixture of rice straw and soybean pod husk as carbon source and urea as nitrogen source with optimum inoculum concentration of 107 spores ml-1 after 96 h of incubation. The temperature of 40°C and pH of production media at 5.5 was optimum for maximum cellulase production. The cellulase was, then, immobilized onto magnetic nanoparticles with binding efficiency of 65.55 per cent. The characterization studies using SEM showed rough surface topography and agglomeration of nanoparticles upon cellulase immobilization. SEM-EDS studies depicted increase in carbon and oxygen elemental composition and TEM micrographs showed an increase in mean diameter of cellulase immobilized nanoparticles. FTIR spectra showed a characteristic peak at 1390 cm-1 after immobilization of cellulase onto magnetic nanoparticles. Characterization studies revealed that the optimum temperature and pH of immobilized enzyme was 60°C and 5.0, respectively and it retained 56.87 per cent of its maximal activity after 6 h of preincubation at 60°C. The Km value for immobilized enzyme (11.76 mM) was slightly higher than that of free enzyme (10.52 mM). The saccharification of sequential acid autoclave-alkali pre-treated rice straw using free and immobilized cellulase resulted in 462.27 and 456.75 mg g-1 reducing sugars, respectively at 72h of incubation. The saccharification efficiency of 53.30 and 52.67 per cent was achieved with free and immobilized cellulase, respectively.ThesisItem Open Access Relating tuber dormancy length with antioxidants and low-temperature sweetening (LTS) in potato cultivars(Punjab Agricultural University, Ludhiana, 2019) Gupta, Himani; Zhawar, Vikramjit KaurWork of relating tuber dormancy with low temperature sweetening (LTS)-resistance and tuber antioxidant content was done in eleven potato cultivars varying in LTS-resistance during cold storage. This work showed that dormancy can be positively related to LTS-resistance where LTS resistance could involve sucrose/starch metabolism oriented more towards anabolism than catabolism, thus beneficial for both dormancy and LTS-resistance. This was seen the best in Lady Rosetta followed by Kufri Frysona and MP/04 578. However vacuolar invertase activity was positively related to hexogenesis in LTS-susceptible cultivars only as LTSresistant cultivars also increased activity of this enzyme upon cold storage, thus enzyme may also be playing other important role during tuber storage. Lady Rosetta was found more dormant at room temperature as well as under cold storage but MP/04 578 and Kufri Frysona were less dormant at room temperature but became more dormant during cold storage. For antioxidant content, Lady Rosetta was found to increase antioxidant content specially catalase with increasing pace of ROS specially H2O2 but other cultivars were poor in this response, thus end up with increasing oxidative toxicity during cold storage. Tubers of Lady Rosetta were found more uniform for size, dormancy related parameters and less effected by seasonal environmental changes during crop growth and storage compared to other cultivars which showed wide variations. This study showed that tuber dormancy can be positively related to LTS-resistance and antioxidant content.ThesisItem Open Access Evaluation of elicitor treatment on biochemical changes in cotton seedlings subjected to high temperature stress(Punjab Agricultural University, Ludhiana, 2019) Hunjan, Harsimran; Sangha, Manjeet KaurIn the present study effect of elicitors; salicylic acid (SA, 50 ppm), calcium chloride (CaCl2, 50ppm), gibberellic acid (GA3, 5ppm) and succinic acid (100ppm recommended by PAU) on heat stress amelioration in seven day old cotton seedlings (Gossypium hirsutum - LH 2298 and LH 2076; Gossypium arboreum - LD 949 and LD 1019) was evaluated in terms of changes in morphophysiological, carbohydrate and protein status and oxidative and antioxidant parameters. High temperature (HT) stresswas given for 1 hr at 40, 45, 50 and 55°C to seven day old cotton seedlings. Seedlings of LH2298, LD949 depicted 50% survival at 55°C followed by LH 2076 (43%) and LD 1019 (41%). HT stress decreased the root and shoot length in seedling which got revived after recovery. Loss of moisture increased with increase in stress temperature. The chlorophyll content decreased from 26-37% with maximum decrease in LD 949. LH 2298 control had highest total carbohydrates, which were negatively affected by HT. The soluble sugars and soluble proteins registered increase. HT stress inceased electrolyte leakage, H2O2 as well as MDA content to minimum in LH 2298 and LD 949. Maximum increase in SOD, POD, APX and GR activity was seen in LH 2298 and LD949 whereas CAT activity declined after HT exposure. Proline, phenolics, ascorbic acid, tocopherols and carotenoids also depicted increase. Seed priming treatment with SA@50ppm was most effective in decreasing the negative effect of HT in terms of improving various estimated parameters in seven day old cotton seedlings, followed by treatment with CaCl2, succinic acid and GA. SA effect was demonstrated maximum in LH 2298 and LD 949. Priming treatment was more effective than seedling spray. In conclusion the given cotton genotypes showed heat tolerance with the order of tolerance as LH 2298>LD 949>LH 2076>LD 1019 and among the elicitors used, SA priming ameliorated the heat stress to maximum. The various parameters in cotton genotypes showed differential response towards heat stress.
