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ThesisItem Open Access A Study of the Toxicity of Nitrosamines under hypercholesterolemic Conditions and Role of Dietary Fibre(Department of Biochemistry College of Basic Sciecnes & Humanities, PAU-Ludhiana, 2001) Mittal, GauravThesisItem Open Access Effect of fibre digesting enzymes on in vitro and in sacco degradation of various feedstuffs in buffalo calves(Department of Biochemsitry, College of Basic Sciences and Humanities PAU, Ludhiana, 2001) Chopra, Smily; Sareen, V. KThesisItem Restricted Identification of drought tolerance related biochemical indices in a wheat recombinant population(Punjab Agricultural University, Ludhiana, 2009) Gulati, Ankit; Asthir, BavitaThe present research was aimed at evaluation of biochemical indices of drought tolerance in wheat. Root and shoot tissue of six wheat genotypes viz.C306, C273, PBW550, PBW534, PBW175 and PBW343 were evaluated at 6 day post germination for growth parameters, relative water content (RWC), membrane stability related parameters, enzyme of carbohydrate metabolism, carbohydrate content and osmolytes accumulation under drought stress (simulated using 8% polyethylene glycol). Stress causes short stature in shoot and elongated roots in all genotypes. C306, C273, PBW534 and PBW175 were found to have longest roots under drought stress. C273, C306 and PBW343 maintained higher RWC under stress. Lowest membrane injury index (MII) and thiobarbituric acid reactive substances (TBARS) were found in C273 and PBW343. Lowest decrease in chlorophyll content (about 21%) was found in PBW175 and PBW343 under stress. The activity of sucrolytic enzymes (acid and neutral invertase) and sucrose synthase (cleavage) decreased whereas sucrose synthesizing enzymes (sucrose phosphate synthase and sucrose synthase synthesis) increased under stress in all the genotypes. Lowest sufficient sucrolytic activity was found in C273 and PBW343 whereas C306 and PBW343 maintained higher activity of sucrose synthesizing enzymes. Amylase activity decreased under stress in endosperm to have lower mobilization of starch. PBW175 and C273 were found to have highest sucrose content showing greater osmotic adjustment. Protein content decreased in contrast to amino acid under stress. C273 was found to have highest proline and amino acid content under stress. To establish cause and effect relationship between biochemical traits and drought tolerance a large randomly derived backcross recombinant inbred line (BCRIL) population derived from (C273/PBW343//PBW343) was studied at vegetative stage. Recombinant lines showing drought tolerance in the field showed an average lower proline content compared to sensitive lines. BCRIL population with low MII were drought sensitive. Drought tolerance however, showed a positive association with membrane stability. The other indices (TBARS, RWC and chlorophyll content) were not related to drought tolerance in field.ThesisItem Open Access Microwave and chemical assisted pretreatment of rice straw for bioethanol production(Punjab Agricultural University, Ludhiana, 2016) Jaspreet Kaur; Taggar, Monica SachdevaThe present study was carried out to develop a process for bioethanol production using microwave chemical pretreatment of rice straw. The comparative studies on different pre-treatment methods of rice straw viz. microwave acid and microwave alkali (at 480 W for 10 min), acid autoclave (for 30 and 90 min) and alkali autoclave (for 30 and 90 min), revealed that acid autoclave pre-treatment (90 min) recorded significantly lowest mean hemicellulose content of 7.53 per cent and microwave alkali pre-treatment (480 W-10 min) recorded significantly lowest mean lignin content of 4.36 per cent. Significantly highest mean cellulose content of 44.56 per cent was recorded in acid autoclave pre-treatment for 90 min. Based on these studies, a two step pre-treatment process involving acid autoclave pre-treatment, followed by microwave alkali pre-treatment for the removal of hemicellulose and lignin, respectively was selected for further studies. The reaction conditions were optimized by using Response Surface Methodology. The optimized conditions for acid autoclave pre-treatment were observed to be 1.90 per cent acid concentration; 51.85 min time and 17.51 soild:liquid ratio. The maximum release of reducing sugars i.e., 16.94 g per 100 g straw and minimum release of furfurals i.e., 0.93 g per 100 g straw was observed under these conditions. The optimized conditions for microwave alkali pre-treatment were observed to be 3.75 per cent alkali concentration; 9.16 min time and 475W microwave power. The lignin content of 2.96 per cent was observed in treated straw under these conditions. Scanning electron microscopy revealed extensive damage of silicified waxy surface and the disruption of the cell wall structure of rice straw after two step pre-treatment process. The cellulase from A. niger was used for enzymatic saccharification of pre-treated rice straw and the reducing sugar content was recorded to be maximum (63.66%) at 72 h after incubation. The maximum ethanol content of 1.16 g and 0.48 g was produced by the fermentation of hydrolysate obtained from enzymatically saccharified and acid autoclave pre-treated rice straw at 120 h after incubation, respectively. A two-step pre-treatment process was thus, an efficient pre-treatment method for bioethanol production.ThesisItem Open Access Identification of biochemical traits for aphid resistance in barley (Hordeum vulgare L.)(Punjab Agricultural University, Ludhiana, 2016) Batra, Nivesh; Kamaljit KaurThe present investigation was carried out to identify the biochemical traits responsible for aphid resistance in barley (Hordeum vulgare L.). For this study, genotypes resistant to aphid attack viz. EC-492253, EC-492255, EC-492350 and BCU-423 and susceptible towards it i.e. PL-426 were taken. The activities of defensive and antioxidative enzymes viz. polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), superoxide dismutase (SOD), β-1, 3-glucanase and chitinase were determined in flag leaves and grains of barley genotypes during different stages of development. Various biochemical constituents i.e. total phenols, total soluble proteins, free amino acids, sugars and tannins were also estimated. The higher activities of PAL, SOD, PPO, β-1, 3-glucanase and chitinase in the flag leaves and grains of resistant genotypes showed their important role against aphid attack. The higher content of total phenols and tannins in the flag leaves and grains of resistant genotypes might attribute towards pest resistance. The higher contents of total soluble proteins, free amino acids and sugars in the flag leaves of susceptible genotype could be responsible for making it a better host for the aphids.ThesisItem Restricted Biochemical traits of microalgal isolates from water logged area of South-west Punjab(Punjab Agricultural University, Ludhiana, 2016) Dalveer Kaur; Taggar, Monica SachdevaFive microalgae designated as MA-1, MA-2, MA-3, MA-4 and MA-5 were isolated from the waterlogged areas of district Muktsar to identify the most potent strain(s) for biofuel production. On the basis of morphological characterization, these microalgal isolates were found to be round, green coloured and unicellular in structure and were tentatively identified as Chlorella. The studies on the effect of salt concentrations, viz. 0.03, 0.05, 0.1, 0.2 and 0.3 M NaCl on the growth of microalgal isolates and C. sorokiniana (standard) revealed that the growth and viable cell count of all the isolates decreased with an increase in salt concentrations. The isolate MA-1 showed maximum growth (A600nm) and viable cell count of 3.26 and 175.2×105 cfu ml-1 at 0.03 M salt concentration. The mean total carbohydrate and lipid content of all microalgal isolates increased up to 0.1 M salt concentration and declined thereafter. The maximum total carbohydrate and lipid content of 20.34 and 18.41 per cent at 5th and 7th day after culturing was observed in isolate MA-1 at 0.1 M NaCl concentration, respectively. The total soluble protein and total chlorophyll content in all the microalgal isolates decreased with an increase in salt concentrations. In isolate MA-1, the maximum total soluble protein content of 10.22 per cent was observed at 0.03 M salt concentration and 7 DAC, while the maximum total chlorophyll content of 21.06 mg g-1 dw was observed at 0.03 M salt concentration and 5 DAC. Hence, higher accumulation of total carbohydrate and lipid content in isolate MA-1 under salt stress suggests that this isolate can be potentially used for biofuel production.ThesisItem Restricted Effect of exogenous phenolic acids on antioxidative defense system of wheat seedlings under salt stress(Punjab Agricultural University, Ludhiana, 2016) Harsimran Kaur; Bhardwaj, Rachana D.In the present study, effect of exogenous phenolic acids on antioxidative defense system of salt stressed wheat seedlings was investigated at 7th day of growth. Electrical conductivity of 10 dS/m was used for imposing salt stress. For observing stress mitigating effects of various phenolic acids, 20 ppm of ferulic, 10 ppm of caffeic, 10 ppm of p-coumaric, 5 ppm of salicylic and 15 ppm of sinapic acids were selected for biochemical studies. Catalase and POX activities were upregulated in the stressed shoots of salt tolerant cultivar by the exogenous use of caffeic and sinapic acids. In comparison to stress, APX activity was also upregulated in stressed seedlings of both cultivars by exogenous use of caffeic and sinapic acids. In stressed seedlings of salt sensitive cultivar, MDHAR activity increased by exogenous use of caffeic, p-coumaric, salicylic and sinapic acids. In roots of Kharchia Local, use of ferulic, para-coumaric and caffeic acids resulted into upregulation of GR activity, whereas in salt sensitive cultivar only caffeic acid caused upregulation of this enzyme. Total phenols also increased in salt stressed seedlings of both the cultivars on application of ferulic, caffeic and salicylic acids which was partially attributed to the downregulation of PPO activity. Proline content increased in HD 2329 by use of different exogenous phenolic acids whereas, in Kharchia Local use of sinapic acid led to enhanced proline content. Glycine betaine content was increased by use of different phenolic acids in the stressed roots of Kharchia Local. On the other hand, exogenous application of sinapic acid led to enhanced glycine betaine content in salt sensitive cultivar. In the shoots of both cultivars, MDA content either decreased or remained unaffected whereas H2O2 decreased in both cultivars by exogenous use of different phenolic acids.ThesisItem Open Access Antioxidant response to salt stress in rice cultivars(Punjab Agricultural University, Ludhiana, 2016) Sukhmanjot; Sharma, NeerjaThe present study was carried out to identify the key components involved in the amelioration of osmotic and oxidative stress caused by salinity in rice. Three salt tolerant genotypes: CSR 27, CSR 30 and GSR 113 and three salt sensitive genotypes: IR 8, IR 64 and Pusa 44 were grown hydroponically and 21 day-old seedlings were exposed to 6 and 12 dSm-1 salt stress. The decrease in the length and dry weight of shoot, root, total chlorophyll and chlorophyll a in tolerant genotypes was significantly higher than sensitive genotypes with increase in salinity after 7 days after salinity treatment (DAS). Chlorophyll b was found to be higher in sensitive genotypes at12 dSm-1. The activity of antioxidant enzymes viz. peroxidase, catalase, ascorbate peroxidase and glutathione reductase was found to be higher in tolerant as compared to sensitive genotypes on exposure to salt stress from 0 to12 dSm-1 after 7 DAS. Activity of superoxide dismutase remained unchanged in tolerant while it was found to be decrease in sensitive genotypes with increase in salinity. H2O2 content was maintained at steady state in tolerant while higher content was observed in sensitive genotypes. The compatible solutes viz. total phenols, flavonoids, total sugars and reducing sugars increased in tolerant as compared to sensitive genotypes under salt stress. Proline and starch content were higher in sensitive as compared to tolerant genotypes. Amino acid content was unaffected in tolerant while it was higher in sensitive genotypes. The ascorbate and total glutathione content increased in tolerant as compared to sensitive genotypes. Malondialdehyde content and electrolyte leakage were higher in sensitive as compared to tolerant genotypes. The increase in Na+/K+ ratio in response to salinity in tolerant was lower as compared to that in sensitive genotypes. Thus, it was concluded that higher activity of antioxidants and compatible solutes led to co-ordinated and regulated response of tolerant genotypes to overcome salt stress.ThesisItem Open Access Effect of nitric oxide on antioxidant defence system of spring maize (Zea mays L.) under high temperature stress(Punjab Agricultural University, Ludhiana, 2016) Khushdeep Kaur; Kamaljit KaurThe present investigation was undertaken to study the effect of nitric oxide on antioxidant defence system of spring maize (Zea mays L.) under high temperature stress (40˚C). For this study, two genotypes of maize viz., LM-11 (relatively susceptible to heat stress) and CML-32 (relatively tolerant to heat stress) were taken into consideration. High temperature stress reduced lengths and dry biomass of roots and shoots of seedlings of both the genotypes. However, priming of seeds with 75µM sodium nitroprusside (SNP) improved seedling growth in terms of their lengths and biomass, under stress conditions. 75µM SNP specifically enhanced CAT activity in seedlings of both the genotypes under high temperature stress. It also increased POX activity in the roots of CML-32 seedlings. This showed that SNP treatment increased the H2O2 scavanging efficiency of CML-32 genotype by enhancing the cumulative activation of CAT and POX in its roots. An increase in SOD activity was observed in roots and shoots of SNP treated LM-11 seedlings that might protect the seedlings against superoxide radicals. SNP decreased the contents of H2O2 and MDA in seedlings of both the genotypes indicating reduced membrane damage and lipid peroxidation. Proline content was also improved by SNP treatment in seedlings of both the genotypes. Thus, exogenous application of nitric oxide (by priming) improved seedling growth and antioxidant potential of maize seedlings exposed to high temperature stress.