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1
Lindeque, Michelle Irene. "Diversity of root nodule bacteria associated with Phaseolus coccineus and Phaseolus vulgaris species in South Africa." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-02162007-170945.
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Crosswhite, F. S., and C. D. Crosswhite. "Nitrogen Fixation in Desert Legumes." University of Arizona (Tucson, AZ), 1988. http://hdl.handle.net/10150/609108.
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Pozo, Alejandro del. "Carbon/nitrogen relations in cereals and legumes." Thesis, University of Reading, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317269.
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Alvarado, Adriana Delgado. "Interactions between carbon and nitrogen metabolism in legumes." Thesis, University of Sheffield, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274992.
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Fajri, Abolhassan. "Nitrogen fixation by pasture legumes : effects of herbicides and defoliation." Title page, table of contents and abstract only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phf1755.pdf.
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Bibliography: leaves 209-254. Experiments detailed in this thesis, evaluate the impact of various herbicides and herbicide mixtures on the growth, nodulation and nitrogen fixation of annual pasture legumes, the efficacy of the herbicides for weed control, and the potential role of mechanical defoliation to replace herbicides, leading to lower cost and more sustainable farming systems.
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Sangtarash, Mohammad Hossein. "Genetic aspects of growth and nitrogen redistribution in pulse legumes." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/46537.
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Metcalf, Sarah Jean. "Symbiotic nitrogen fixation and establishment of six Montana native legumes species." Thesis, Montana State University, 2005. http://etd.lib.montana.edu/etd/2005/metcalf/MetcalfS0805.pdf.
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Devkota, Dibya. "Habitat, isolation, identification and nitrogen fixation of Rhizobiaceae associated with rangeland legumes from Wyoming, USA." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1313917311&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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Ng, Ying-sim. "Symbiotic nitrogen fixation by native woody legumes (leguminosae) in Hong Kong, China." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B41897122.
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Yates, Ronald John. "Symbiotic interactions of geographically diverse annual and perennial Trifolium spp. with Rhizobium leguminosarum bv. trifolii /." Murdoch University Digital Theses Program, 2008. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20100330.93305.
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Munyinda, Kalaluka. "Efficiency of water and nitrogen use by wheat and legumes in Zambia." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=75446.
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Maximum wheat (Triticum aestivum L.) yields in Zambia were obtained with weekly irrigation at 85% of class A pan evaporation during the whole irrigation interval and split application of urea N of which the initial portion of the fertilizer was either broadcast and incorporated or broadcast after the crop had established itself. This corresponded with maximum utilization of fertilizer N. The proportion of N derived from fertilizer was independent of fertilizer placement at various water regimes and N utilization was primarily a function of water availability.Two nonnodulating soybean (Glycine max L.) cultivars, Clark RJ1 and N77, or in their absence Pearl millet (Panicum glaucum L.) were judged to be appropriate reference crops for estimating N$ sb2$ fixation by soybeans using $ sp{15}{ rm N}$ isotope dilution techniques. A local soybean cultivar, Magoye, was rated highest among three cultivars tested for its ability to support N$ sb2$ fixation by Bradyrhizobium japonicum and contributed biologically fixed N$ sb2$ to a subsequent wheat crop.
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Cathey, Sarah Elizabeth. "Growth and nitrogen fixation of legumes native to the longleaf-wiregrass ecosystem." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0013280.
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Ng, Ying-sim, and 吳英嬋. "Symbiotic nitrogen fixation by native woody legumes (leguminosae) in Hong Kong, China." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B41897122.
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Rial, Lovera K. E. "Evaluation of cultivation, legume undersowing and nitrogen interventions on wheat development." Thesis, Coventry University, 2015. http://curve.coventry.ac.uk/open/items/164277f7-8c38-47e4-aaf8-9959494dc390/1.
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Agriculture is facing increasing pressures to produce food that meets specific market and/or nutrition requirements, while using inputs in such a way that can ensure economic and environmental goals more efficiently. Two field experiments were conducted in 2013 and 2014 at the Royal Agricultural University’s Harnhill’ Manor Farm, Cirencester, UK to evaluate the influence of selected cultivation techniques, N fertilisation and undersowing legumes on spring wheat growth and development. To explore, in particular, the yield components contributing to grain yield and quality, as well as weed pressure influences together with changes in soil mineral N (SMN) content. Cultivation techniques included conventional tillage (CT), high intensity non-inversion tillage (HINiT) and low intensity non-inversion tillage (LINiT); mineral N fertilisation rates of 0, 70, 140 and 210 kg N ha-1 and two undersown legume species, black medic and white clover, plus no undersowing treatment. The performance of the management practices was strongly influenced by the weather. In 2013, under dry weather conditions, LINiT seems to be a suitable alternative to CT, while N fertilisation did not encourage greater grain yield. In 2014, CT appears to be a more reliable practice, while the application of up to 140 kg N ha-1 seemed to be enough to increase grain yield. Dry weather conditions at the time of broadcasting did not allow the undersowing species to be fully established, resulting in no effects on weed control and crop growth. In 2013, the initial poor plant establishment and slow crop growth under LINiT was compensated for by the soils ability to retain moisture, and thereby reducing crop water stress during the dry periods. This finally resulted in statistically similar grain yield to CT. In 2014 when water was not a limiting factor, poor plant establishment and crop growth, low SMN content and high weed pressure under LINiT resulted in lower grain yield than CT. In both years, HINiT resulted in low SMN content and high weed pressure resulting in poor grain yield. Across experiments, HINiT and LINiT saved energy-use and production costs, but CT could be more energy-use efficient and have high economic return if higher grain yield is assured. N fertilisation significantly promoted wheat growth, although under dry conditions with higher residual soil N, the N fertilisation did not increase yield. Under low SMN level applying up to 140 kg N ha-1 increased grain yield produced, but N fertilisation is energy consuming and its use does not always ensure a higher economic return.
15
Peoples, MB, J. Brockwell, DF Herridge, IJ Rochester, BJR Alves, S. Urquiaga, RM Boddey, et al. "The contributions of nitrogen-fixing crop legumes to the productivity of agricultural systems." Symbiosis, 2009. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1001480.
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Data collated from around the world indicate that, for every tonne of shoot dry matter produced by crop legumes, the
symbiotic relationship with rhizobia is responsible for fixing, on average on a whole plant basis (shoots and nodulated
roots), the equivalent of 30-40 kg of nitrogen (N). Consequently, factors that directly influence legume growth (e.g. water
and nutrient availability, disease incidence and pests) tend to be the main determinants of the amounts of N2 fixed.
However, practices that either limit the presence of effective rhizobia in the soil (no inoculation, poor inoculant quality),
increase soil concentrations of nitrate (excessive tillage, extended fallows, fertilizer N), or enhance competition for soil
mineralN (intercropping legumes with cereals) can also be critical. Much of the N2 fixed by the legume is usually removed
at harvest in high-protein seed so that the net residual contributions of fixed N to agricultural soils after the harvest of
legume grain may be relatively small. Nonetheless, the inclusion of legumes in a cropping sequence generally improves the
productivity of following crops. Whilesome of these rotational effects may be associated with improvements in availability
ofN in soils, factors unrelated to N also play an important role. Recent results suggest that one such non-N benefit may be
due to the impact on soil biology of hydrogen emitted from nodules as a by-product of'N, fixation.
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Peoples, MB, IJ Rochester, BJR Alves, S. Urquiaga, RM Boddey, FD Dakora, S. Bhattarai, et al. "The contributions of nitrogen-fixing crop legumes to the productivity of agricultural systems." Balaban, 2009. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1001675.
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Data collated from around the world indicate that, for every tonne of shoot dry matter produced by crop legumes, the
symbiotic relationship with rhizobia is responsible for fixing, on average on a whole plant basis (shoots and nodulated
roots), the equivalent of 30-40 kg of nitrogen (N). Consequently, factors that directly influence legume growth (e.g. water
and nutrient availability, disease incidence and pests) tend to be the main determinants of the amounts of N2 fixed.
However, practices that either limit the presence of effective rhizobia in the soil (no inoculation, poor inoculant quality),
increase soil concentrations of nitrate (excessive tillage, extended fallows, fertilizer N), or enhance competition for soil
mineralN (intercropping legumes with cereals) can also be critical. Much of the N2 fixed by the legume is usually removed
at harvest in high-protein seed so that the net residual contributions of fixed N to agricultural soils after the harvest of
legume grain may be relatively small. Nonetheless, the inclusion of legumes in a cropping sequence generally improves the
productivity of following crops. Whilesome of these rotational effects may be associated with improvements in availability
ofN in soils, factors unrelated to N also play an important role. Recent results suggest that one such non-N benefit may be
due to the impact on soil biology of hydrogen emitted from nodules as a by-product of'N, fixation.
17
Habaunga, Sem Simon. "Characterization of transgenic Lotus japonicus containing the Arabidopsis thaliana ethylene receptor (ETR1-1) gene /." [St. Lucia, Qld.], 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18170.pdf.
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Abi-Ghanem, Rita. "Optimizing biological nitrogen fixation and evaluating Iraqi extension education." Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Dissertations/Summer2009/R_Abi-Ghanem_070909.pdf.
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Holmberg, Mitchell Blake. "Alternative nitrogen for subsequent southern switchgrass (Panicum virgatum L.) production using cool-season legumes." Thesis, Mississippi State University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1554945.
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Switchgrass (Panicum virgatum L.) has become an important bioenergy crop. Warm, winter temperatures in the southeastern USA allow for fall establishment and winter growth of cool-season legumes that may provide nitrogen to the spring perenniating crop of switchgrass. Data indicates variation due to year and location, but hairy vetch plots provided a greater nitrogen percentage in the subsequent biomass production of switchgrass. In 2011, switchgrass fertilized with 56 kg ha−1 N was greater than the control and in 2012 it was greater than the 28 kg ha−1 N treatment. Variation around the means prevented clear separation among other treatments. The data also showed that hairy vetch had the greatest volunteer frequency and cover percentage throughout the year. Data from the Dairy Farm showed no differences in yields due to a lack of field management the previous years and only ball clover increased its coverage over time.
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Landrum, Jason Paul. "Movement of new nitrogen through oceanic food webs." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28151.
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Thesis (M. S.)--Biology, Georgia Institute of Technology, 2009.Committee Chair: Joseph Montoya; Committee Member: Ellery Ingall; Committee Member: Emanuele DiLorenzo; Committee Member: Marc Weissburg; Committee Member: Mark Hay.
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Tsiadi, Alexandra. "Nitrogen bubble refining of sunflower oil." Thesis, University of Surrey, 1998. http://epubs.surrey.ac.uk/804355/.
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Nyalemegbe, Kenneth K. "Growth, nodulation and nitrogen fixation of the faba bean (Vicia faba L.) under contrasting soil moisture conditions and under varied crop density and shading." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240164.
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23
Nandasena, Kemanthi Gayathri. "Rapid evolution of diversity in the root nodule bacteria Biserrula plecinus L." Nandasena, Kemanthi Gayathri (2004) Rapid evolution of diversity in the root nodule bacteria Biserrula plecinus L. PhD thesis, Murdoch University, 2004. http://researchrepository.murdoch.edu.au/221/.
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Biserrula pelecinus L. has been introduced to Australia from the Mediterranean region, in the last decade due to many attractive agronomic features. This deep rooted, hard seeded, acid tolerant and insect resistant legume species provides high quality food for cattle and sheep, and grows well under the harsh edaphic and environmental conditions of Australia. In 1994, B. pelecinus was introduced to a site in Northam, Western Australia where there were no native rhizobia capable of nodulating this legume. The introduced plants were inoculated with a single inoculant strain of Mesorhizobium sp., WSM1271. This study investigated whether a diversity of rhizobia emerged over time. A second objective was to investigate the possible mechanisms involved in the diversification of rhizobia able to nodulate B. pelecinus.
Eighty eight isolates of rhizobia were obtained from nodules on B. pelecinus growing at the Northam site in August 2000, six years after introduction. These plants were self-regenerating offspring from the original seeds sown. Molecular fingerprinting PCR with RPO1 and ERIC primers revealed that seven strains (novel isolates) had banding patterns distinct from WSM1271 while 81 strains had similar banding patterns to WSM1271. A 1400 bp internal fragment of the 16S rRNA gene was amplified and sequenced for four of the novel isolates (N17, N18, N45 and N87) and WSM1271. The phylogenetic tree developed using these sequences clustered the novel isolates in Mesorhizobium. There were >6 nucleotide mismatches between three of the novel isolates (N17, N18, N87) and WSM1271 while there were 23 nucleotide mismatches between N45 and WSM1271.
When B. pelecinus cv. Casbah was inoculated with the novel isolates, five (N17, N18, N39, N46 and N87) yielded <40% of the shoot dry weight of the plants inoculated with the original inoculant (WSM1271). Novel isolates N15 and N45 were completely ineffective on B. pelecinus cv. Casbah.
Physiological experiments to test the ability of the novel isolates and WSM1271 to grow on 14 different carbon sources (N acetyl glucosamine, arabinose, arbutine, dulcitol, beta-gentiobiose, lactose, maltose, melibiose, D-raffinose, saccharose, L-sorbose, D-tagatose, trehalose and D-turanose) as the sole source of carbon, intrinsic resistance to eight different antibiotics (ampicillin, chloramphenicol, gentamicin, kanamycin, nalidixic acid, spectinomycin, streptomycin and tetracycline) and pH tolerance (pH 4.5, 5.0, 7.0, 9.0) revealed that the novel isolates had significantly different carbon source utilization patterns to WSM1271. However, pH tolerance and intrinsic resistance to antibiotics were similar between the novel isolates and WSM1271 except for streptomycin (100 mcg/ml). Novel isolates N17, N18, N46 and N87 were susceptible for this antibiotic while the other novel isolates and WSM1271 were resistant.
Host range experiments were performed for the novel isolates N17, N18, N45, N87, WSM1271 and two other root nodule bacteria (RNB) previously isolated from B. pelecinus growing in the Mediterranean region (WSM1284 and WSM1497) for twenty one legumes (Amorpha fruticosa, Astragalus adsurgens, Astragalus membranaceus, Astragalus sinicus, Biserrula pelecinus cv Casbah, Dorycnium hirsutum, Dorycnium rectum, Glycyrrhiza uralensis, Hedysarum spinosissimum, Leucaena leucocephala, Lotus corniculatus, Lotus edulis, Lotus glaber, Lotus maroccanus, Lotus ornithopodioides, Lotus parviflorus, Lotus pedunculatus, Lotus peregrinus, Lotus subbiflorus, Macroptilium atropurpureum, and Ornithopus sativus). Only isolate N17 have the same host range as WSM1271 in that they both nodulated B. pelecinus and A. membranaceus, while the other three novel isolates, WSM1284 and WSM1497 had a broader host range than WSM1271. Three isolates N18, N45 and N87 formed small white nodules on M. atropurpureum, in addition to nodulating the above hosts. Isolates N18 and N45 also nodulated A. adsurgens while N45 was the only isolate to nodulate L. edulis. Isolate N87 was the only isolate to nodulate A. fruticosa. WSM1497 nodulated A. adsurgens, A. membranaceus, B. pelecinus and L. corniculatus while WSM1284 was a promiscuous strain that nodulated 16 host species out of the 21 tested. A 710 bp internal region of nifH, a 567 bp internal region of nodA and a 1044 bp internal region of intS were sequenced for N17, N18, N45, N87 and WSM1271. The sequence comparison showed that the sequences of the above three genes of the four novel isolates were identical to that of WSM1271.
Eckhardt gel electrophoresis revealed that WSM1271, three other RNB isolates from B. pelecinus from the Mediterranean region and isolate N18 each have a plasmid of approximately 500 kb while N17, N45 and N87 are plasmid free. Probing of the plasmid DNA from the Eckhardt gel with nifH and nodA probes indicated that these two genes were not located on the plasmid.
Furthermore, the results of this study demonstrated that 92% of the nodules on B. pelecinus growing in the Northam site six years after the introduction of this plant were occupied by the inoculant strain and the N2 fixation efficiency of the progeny strains of WSM1271 remain similar to the mother culture. This study also showed that the carbon source utilization pattern, intrinsic antibiotic resistance and pH range of the progeny strains of WSM1271 remain relatively similar, except for few variations in carbon source utilization patterns.
This thesis clearly demonstrated that phenotypicaly, genetically and phylogenetically diverse strains capable nodulating B. pelecinus evolved through symbiotic gene transfer from the inoculant strain to other soil bacteria within six years. The presence of intS, and the evidence of gene transfer between these Mesorhizobium strains indicates that transfer of symbiotic genes may have occurred via a symbiosis island present in WSM1271.
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Kabbara, Salam. "EFFECT OF COOKING TIME AND TEMPERATURE ON HARDNESS AND ANTI-NUTRITIONAL FACTORS OF TEPARY BEAN." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275284.
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Hardy, Zolelwa. "Functional and nutritional characteristics of Bambara groundnut milk powder as an ingredient in yoghurt." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2340.
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Thesis (MTech (Food Technology))--Cape Peninsula University of Technology, 2016.The aim of this study was to evaluate Bambara groundnut (BGN) milk subjected to spray drying with a view to establish functional, nutritional and physical properties as an ingredient in BGN yoghurt production. BGN milk powder (BGNMP) was successfully produced employing the spray drying technology. Maltodextrin was used as the drying carrier to elevate total solids of BGNM prior to spray drying. There were three levels of maltodextrin (5, 10 and 15%) employed and 10% was ideal. The optimum spray drying parameters were estimated to be the following; inlet temperature (150oC), outlet temperature (74oC), air pressure (3 bars), flow rate (10% or 16mL/min), and air flow (42.9 m3/h). The functional properties evaluated revealed high water solubility capabilities, making BGNMP readily soluble in water, which is one of the most crucial aspects of milk powders. The water solubility index of BGNMP at all maltodextrin levels ranged from 85.15 to 90.25%. There was a significant (p < 0.05) difference amongst BGNMP (5, 10, and 15%) in colour parameters (lightness, yellowness, redness, chroma and hue angle). BGNMP indicated to have a red and yellow colour, but yellow was more dominant. The particle size and particle size distribution of BGNMP ranged from 86.13 to 162.35 μm and 84.04 to 157.0 μm, respectively and did not differ significantly (p > 0.05).
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Gathumbi, Stanley Mwangi. "Nitrogen sourcing by fast-growing legumes in pure and mixed species fallows in western Kenya." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322531.
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Doel, J. M. "Accumulation and recovery of nitrogen in mixed farming systems using legumes and other fertility building crops." Thesis, Coventry University, 2012. http://curve.coventry.ac.uk/open/items/9dd4b790-1672-4b0e-9104-09439ddde7a2/1.
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Fertility-building crops (FBCs) offer the opportunity to alleviate the costs of inorganic fertiliser by providing an alternative supply of available nitrogen (N) in soils. A survey of relevant literature reviewed the types of FBCs, their nitrogen accumulation potentials, residue characteristics, and subsequent release patterns. It also identified a paucity of data concerning the response of different species to UK climatic, soil, and management conditions. In order to investigate these relationships further pot and field trials were established in 2007 at the Royal Agricultural College, Cirencester (SP 00481 01382) and at Coates Manor Farm (SO 98473 00402) on Sherborne series (typical Cotswold) soils, to investigate the biology and morphology of FBCs potentially suitable for short term fertility-building, their accumulation of N under field conditions, and its subsequent recovery within test crops. Data so obtained was used as a verification and refinement tool for the FBC model (Cuttle et al, 2003), a simple, commercially applicable, rotation-based model which can be applied to both organic and conventional production systems. Nine leguminous and two non-leguminous FBC treatments were established in April 2007 by straight sowing, followed by mulching at the conclusion of the nitrogen accumulation phase and by undersowing in spring barley (Hordeum sativum). The recovery test crops (winter and spring wheat Triticum aestivum L.) were established in September 2007 and March 2008. All FBCs established successfully. Above-ground dry matter (DM) yield and residue quality (C:N ratio) of FBCs varied significantly (P<0.05) between crops and cropping regimes with a significant correlation (r2=0.418) between DM yields and C:N ratios. FBCs and cropping regimes had significant effects (P<0.001 and P<0.05 respectively) on potential mineralisable nitrogen (PMN) levels in the soil and on the grain yields of winter and spring wheat test crops. Straight sown Lupinus albus, Trifolium pratense, Trifolium repens and a legume mixture resulted in higher winter wheat grain yields. However, the opportunity cost associated with straight sowing (i.e. the gross margin foregone from a spring barley crop) meant that the rotation would probably not be viable economically. Undersown Medicago lupulina, Vicia villosa, T. pratense, T. repens and the legume mixture gave worthwhile yield increases in spring wheat without incurring a yield penalty in the spring barley cover crop. Following enhancement and using actual data from the trials, the FBC model (Cuttle et al, 2003) provided encouraging predictions (R>0.6) for soil mineral nitrogen (SMN) and key parameters were identified for future use. It was concluded that FBCs established for short term soil fertility building could provide a worthwhile enhancement of soil N levels and grain yields in a conventional arable rotation, particularly in spring wheat following FBCs undersown in spring barley. It was also concluded that the FBC model (Cuttle et al, 2003), following further enhancement, and using additional data from these and other similar trials, could provide reasonably accurate estimates of SMN to aid more precise applications of N fertiliser in the future.
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Idouraine, Ahmed 1948. "NUTRITIONAL QUALITY AND ORGANOLEPTIC ACCEPTABILITY OF AKARA PREPARED FROM GERMINATED TEPARY BEANS." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276498.
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Tepary bean (Phaseolus acutifolius G.), was germinated for 48 hours and used for akara preparation. Raw and germinated teparies and uncooked and cooked akara were analyzed for proximate and amino acid composition, vitamin A and ascorbic acid contents, trypsin inhibitor activity (TIA), and compared to that obtained using cowpeas. Protein and amino acid composition of cowpeas and raw teparies were similar. Vitamin A and ascorbic acid contents were low. Germination increased vitamin A and ascorbic acid contents but had little effect on protein content, amino acid composition, and TIA. In cooked akara, protein content dropped from 21.03-23.77% to 12.05-14.36%, ascorbic acid from 5.76-8.88% to 1.22-1.60%, and TIA from 12.41-12.98% to 9.15-11.25%. For sensory evaluation, no significant difference in color, texture, and flavor was found but for the overall acceptability, akara prepared from raw teparies was significantly (P ≤ 0.05) preferred to akara prepared using cowpeas and germinated teparies.
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Motta, Eder Alexandre Minski da. "Agronomic performance in Paspalum interspecific hybrids subjected to nitrogen application rates or in mixture with temperate legumes." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/180617.
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Plicatula is a taxonomic group within of the genus Paspalum that contains interesting species considering their phenotypic diversity for forage traits, and some of these species have been improved through artificial interspecific hybridization. Nitrogen (N) is an important limiting factor to produce biomass. Forage legumes contribute with symbiotic N2 fixation and can increase biomass yield and the nutritive value of the pastures. The objectives of this thesis were: (i) evaluate dry matter yield (DMY), N use efficiency (NUE), nutritive value, cold tolerance and plant persistence in hybrids of Paspalum plicatulum x P. guenoarum subjected to N application rates, (ii) compare biomass yield and nutritive value of the grass–legume system to a grass–N fertilizer system, and (iii) select the best hybrids for new steps within the breeding program. The study was conducted from September 2015 to May 2017. The experimental design was a randomized complete block in split-plot arrangement with three replicates. Treatments were five N rates (0, 60, 120, 240, and 480 kg N ha-1 N), and one grass-legumes mixture (Trifolium repens + Lotus corniculatus) as whole plots, and six genotypes (1020133, 102069, 103084, 103061, P. guenoarum ecotype Azulão and Megathyrsus maximus cv. Aruana used as a control) as subplots. Nitrogen rates of 240 and 480 kg N ha-1 increased Total-DMY, Leaf-DMY, cold tolerance and persistence but decreased NUE. Higher NUE was obtained with N rates between 60 and 120 kg N ha-1. Total-DMY for grass-legume mixture was similar to the N rates of 60 and 120 kg N ha-1. Hybrid 1020133 had Total-DMY similar to Azulão and Aruana, as well as Leaf-DMY greater than Aruana. Hybrid 1020133 showed greater cold tolerance and exhibited greater NUE at 60 kg N ha-1 than the other genotypes. At the N rate of 480 kg N ha-1 increased crude protein (27%) and digestibility (4%) and decreased neutral (6%) and acid (7%) detergent fiber compared to the 0 kg N ha-1. Grass-legume mixture showed greater nutritive value compared to N-fertilized grass. Hybrid 103061 had greater crude protein and digestibility and lower neutral and acid detergent fiber than Azulão and Aruana. Therefore, there is opportunity to increase DMY, NUE, cold tolerance and plant persistence, and improve the nutritive value through genotype selection and N management. In addition, grass-legume mixture showed greater nutritive value than N-fertilized grass and can be an alternative practice to replace to the application of N fertilizer up to the rate of 120 kg N ha-1. Hybrids 1020133 and 103061 should be indicated for new studies, such as seed production and animal performance.
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Maistry, Pravin Mark. "Aspalathus and Podalyria legumes balance acquisition of phosphorus and nitrogen for growth in nutrient poor fynbos soils." Doctoral thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/15705.
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Legume species nodulate and grow successfully in the Core Cape Subregion, a Mediterranean-climate ecosystem with fynbos vegetation found on infertile soils. The physiological mechanisms enabling tolerance of low availability of phosphorus (P) are yet to be reported in Cape legume species such as Aspalathus linearis and Podalyria calyptrata; species that demonstrated traits typical of plants from nutrient poor soils. In the three research chapters of the thesis, it was anticipated that low P supply would limit plant growth and increase expression of traits for P acquisition.
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Tiveron, Ana Paula. "Atividade antioxidante e composição fenólica de legumes e verduras consumidos no Brasil." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/11/11141/tde-20102010-101541/.
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As hortaliças são alimentos amplamente consumidos na dieta dos brasileiros. Há alguns anos, estudos sobre compostos presentes em vegetais, como os carotenóides, vitaminas, fibras e compostos fenólicos vem sendo bastante explorados devido aos seus possíveis efeitos biológicos e benefícios à saúde humana. Os compostos fenólicos são produtos do metabolismo secundário das plantas e se destacam principalmente por seu poder antioxidante. O objetivo deste trabalho foi avaliar os compostos fenólicos e a atividade antioxidante em algumas hortaliças consumidas no Brasil. Os métodos utilizados foram o do radical livre DPPH e ABTS, auto-oxidação do sistema -caroteno/ácido linoléico, redução do ferro, estabilidade oxidativa em Rancimat e identificação química por meio da técnica de cromatografia gasosa acoplada a espectrômetro de massas. Extratos etanólicos foram utilizados em todas as análises. O teor de compostos fenólicos variou entre 1,2 a 16,9 mg/g, sendo que a cenoura apresentou a menor quantidade e a alface a maior. As hortaliças que apresentaram a maior atividade antioxidante foram a alface (54,9% e 0,45 µmol Fe2+/mg), nos métodos do DPPH e FRAP , respectivamente, o açafrão (111,8µM trolox/g e 92,8%), nos métodos ABTS+ e -caroteno, o agrião e o brócolis no método do Rancimat (fator de proteção 1,29). Além dessas, a alcachofra, espinafre, e aspargo também apresentaram atividade antioxidante considerável. Os compostos fenólicos mais frequentemente encontrados nas amostras pela técnica de CG-EM foram os ácidos ferúlico, caféico e p-cumárico. O ácido ascórbico presente também contribuiu para a atividade antioxidante de alguns vegetais. Desta forma, pode-se verificar boa atividade antioxidante de várias hortaliças, ressaltando assim a importância em uma dieta equilibrada destes vegetais.Vegetables are widely consumed foods in the diet of Brazilians. A few years ago, studies on compounds present in vegetables such as carotenoids, vitamins, fibers and phenolic compounds have been conducted due to their biological effects and benefits to human health. Phenolic compounds are distinguished mainly by their antioxidant power. The aim of this study was to evaluate the phenolic compounds and antioxidant activity in some vegetables consumed in Brazil. The methods for evaluating the antioxidant activity used were the DPPH free radical and ABTS, -carotene bleaching, reduction of Fe3+, oxidative stability in Rancimat, while the chemical composition used the gas chromatography - mass spectrometry technique (GC-MS). Ethanol extracts were used in all analysis. The content of phenolic compounds ranged from 1.2 to 16.9 mg / g, with carrots presenting the lowest amount and lettuce the highest. The vegetables with the highest antioxidant activity were lettuce (54.9% and 0.45 mmol Fe2+/ mg), through DPPH and FRAP methods, respectively, saffron (111.8 mM trolox / g and 92.8%) through the ABTS+ and -carotene methods, watercress and broccoli through the Rancimat method (protective factor 1.29). Besides these, the artichoke, spinach, and asparagus also showed considerable antioxidant activity. Phenolic compounds most frequently found through the GCMS technique were ferulic acid, caffeic acid and p-coumaric acid. Ascorbic acid also contributed to the antioxidant activity of some vegetables. Generally, it is confirmed the good antioxidant activity of some vegetables, emphasizing its importance in a balanced diet.
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Kadel, Khem L. "Forward Genetic Characterization of Medicago truncatula Tnt1 Insertion Mutants Defective in Nodule Development and Symbiotic Nitrogen Fixation." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc801877/.
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Legumes are unique plants because they form special structures “nodules”, via symbiotic relationships with rhizobial bacteria present in the soil. Once rhizobia mature inside nodules, they fix atmospheric nitrogen providing a source of bioavailable nitrogen to the plant. To discover novel genetic components involved in the legume-rhizobia symbiosis by using forward genetic screening, we have isolated Medicago truncatula Tnt1 insertion mutants in the R108 ecotype, which are defective in nodule development and symbiotic nitrogen fixation in response to Sinorhizobium meliloti. Out of three mutants NF11044, NF11217 and NF8324, one of the mutants showed brown nodules and Fix- phenotype that is defective in symbiotic nitrogen fixation. The other two mutants showed white nodules and Fix- phenotype, also indicator of defects in symbiotic nitrogen fixation. To identify the underlying mutation causing the phenotype, we have developed molecular genetic markers by obtaining genomic sequences flanking the Tnt1 insertions by TAIL-PCR and Illumina sequencing. To carry out co-segregation analysis, back-crossed BC1F2 segregating populations were obtained. These are being phenotyped, genotyped and analyzed for co-segregation of the phenotype with the Tnt1 genetic markers. Back-crossing also has the effect of reducing the Tnt1 insertions, which are not linked to the nodulation defective phenotypes. Out of the three mutants, NF8324 harbors exactly the same insertion as in the rsd-1 Tnt1 mutant NF11265. The defect in NF11217 is caused by a Tnt1 insertion in the previously described PLC gene; the site of this insertion is close to that found in a different mutant, NF0217. For mutant NF11044, we developed linkage markers that place the defective locus on chromosome 7. To further characterize co-segregation in NF11044, a mapping population has been created by crossing the mutant with other ecotypes: A17 and A20. We tested mutants and wild type plants with linkage marker A20 X NF11044 BC1F2 that segregates 3:1(wild type: mutant). The recombination frequency ratio is similar as compared to back-crosses to ecotype R108. However, we did not observe mutant phenotypes in the A17 X NF11044 BC1F2 population. Future identification of the defective gene and functional characterization of it once it is identified will be carried out to better understand the mechanism of nodule organogenesis and symbiotic nitrogen fixation.
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Mansur, Irdika. "Diversity of rhizobia nodulating the tree legumes Acacia mangium and Paraserianthes falcataria and their interaction with arbuscular mycorrhizal fungi in young seedlings." Thesis, University of Kent, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310199.
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Huang, Ying-Sheng. "Evidence for Multiple Functions of a Medicago Truncatula Transporter." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc699903/.
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Legumes play an important role in agriculture as major food sources for humans and as feed for animals. Bioavailable nitrogen is a limiting nutrient for crop growth. Legumes are important because they can form a symbiotic relationship with soil bacteria called rhizobia that results in nitrogen-fixing root nodules. In this symbiosis, rhizobia provide nitrogen to the legumes and the legumes provide carbon sources to the rhizobia. The Medicago truncatula NPF1.7/NIP/LATD gene is essential for root nodule development and also for proper development of root architecture. Work in our lab on the MtNPF1.7/MtNIP/LATD gene has established that it encodes a nitrate transporter and strongly suggests it has another function. Mtnip-1/latd mutants have pleiotropic defects, which are only partially explained by defects in nitrate transport. MtNPF1.7/NIP/LATD is a member of the large and diverse NPF/NRT1(PTR) transporter family. NPF/NRT1(PTR) members have been shown to transport other compounds in addition to nitrate: nitrite, amino acids, di- and tri-peptides, dicarboxylates, auxin, abscisic acid and glucosinolates. In Arabidopsis thaliana, the AtNPF6.3/NRT1.1( CHL1) transporter was shown to transport auxin as well as nitrate. Atchl1 mutants have defects in root architecture, which may be explained by defects in auxin transport and/or nitrate sensing. Considering the pleiotropic phenotypes observed in Mtnip-1/latd mutant plants, it is possible that MtNPF1.7/NIP/LATD could have similar activity as AtNPF6.3/NRT1.1(CHL1). Experimental evidence shows that the MtNPF1.7/NIP/LATD gene is able to restore nitrate-absent responsiveness defects of the Atchl1-5 mutant. The constitutive expression of MtNPF1.7/NIP/LATD gene was able to partially, but not fully restore the wild-type phenotype in the Atchl1-5 mutant line in response to auxin and cytokinin. The constitutive expression of MtNPF1.7/NIP/LATD gene affects the lateral root density of wild-type Col-0 plants differently in response to IAA in the presence of high (1mM) or low (0.1 mM) nitrate. MtNPF1.7/NIP/LATD gene expression is not regulated by nitrate at the concentrations tested and MtNPF1.7/NIP/LATD does not regulate the nitrate-responsive MtNRT2.1 gene. Mtnip-1 plants have an abnormal gravitropic root response implicating an auxin defect. Together with these results, MtNPF1.7/NIP/LATD is associated with nitrate and auxin; however, it does not act in a homologous fashion as AtNPF6.3/NRT1.1(CHL1) does in A. thaliana.
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Hamel, Chantal. "Mycorrhizal effects on 15N-transfer from legume to grass intercrops, plant growth and interspecific competition." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74601.
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N-transfer from legume to grass when the two were intercropped in the field and the mechanisms of this transfer were studied. Studies involving either alfalfa-grasses or soybean-corn intercrops, were undertaken. Mycorrhizal and P-supplemented (to compensate for the lack of mycorrhizae) intercrops were compared. In these studies, the legume component of intercrops was labelled with $ sp{15}$N and any excess of the label was looked for in the associated grass plants.There was no reversal of N transport at the legume-fungus interface. N-transfer from legume to grass must therefore, proceed via excretion of N by legume roots and subsequent uptake by grass roots. Soil microorganisms and proximity of plant root systems are important factors affecting N-transfer. Mycorrhizae enhance the transfer by increasing the absorptive efficiency of the receiver plants.
Mycorrhizal fungi enhance the competitiveness of the most mycotrophic component of the mixtures by either improving P uptake or the general nutrient balance of the plant. Mycorrhizal inoculation can decrease the level of P competition between corn and soybean by increasing the availability of P.
The observation that mycorrhizal plants differ in many regards from P-supplemented plants, emphasize the generally poor comprehension of the mycorrhizal symbiosis.
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Mendonça, Marco Antonio de Freitas. "Crescimento de plantas jovens de leguminosas arbóreas em resposta à adubação nitrogenada e inoculação de Rizóbios em Argissolo Vermelho Amarelo e Latossolo Amarelo na Amazônia Central." Universidade Federal do Amazonas, 2012. http://tede.ufam.edu.br/handle/tede/3044.
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Previous issue date: 2012-06-21Little one knows on the efficiency of the answer of N2 fixation in legume tree native of the Amazonian when inoculated with specific or homolog rhizobia to demonstrate the use potential of microbial inoculants to stimulate biological technologies in the agricultural production and recovery of soils. The objective of this work was to evaluate the effect of the inoculation with Rhizobia about the growth and biomass distribution in three native legume trees. The selected species were: Inga thibaudiana var. thibaudiana, I. nobilis and Erythrina fusca. Two soils acid of the firm earth they were appraised: yellow oxisol collected under pasture and yellow red ultisol collected in agroforestry systems. The species were sowed in sand and transplanted for bags with 2 soil kg and led in the nursery. In the two soils three forms of supply of N were tested: control treatment (plants not inoculated and without mineral N); plants supplied with 80 kg of N hectare-1; and, plants inoculated with a cocktail of strains of Rhizobia of the INPA collection. Monthly the length of the stem of the plants was evaluated. The crop was made to the 93 days for E. fusca and 165 and 151 days for I. thibaudiana and I. nobilis, being determined the distribution of dry biomass in the leaves, roots, stem and nodules of the plant. The number of nodules was counted and made determinations of leave-N and total-N of the plants. The experimental design was it entirely random, in factorial arrangement 2 x 3 (soils x forms of supply of N), with 9 repetitions. The inoculation with Rhizobia influences the growth, biomass partition, nodulation indicators and absorption of N, having differences in the answer depending on the appraised species. The specificity character or of promiscuity in the selected legume tree is decisive in the answer of the species the inoculation. All the species of legume tree researched adapted better to the soil ultisol compared to the oxisol. It was demonstrated that the employed strains as inoculants in I. thibaudiana var. thibaudiana formed processes of fixation of more efficient N2 than when inoculated in I. nobilis. For E. fusca, considered of behavior non specific as the compatibility with native Rhizobia the practice of the inoculation favored the symbiotic processes in soil oxisol compared to ultisol. It was evidenced that the inoculation technique with Rhizobia has alternative potentiality for supply of nitrogen for the plants, compared the nitrogen fertilization.
Pouco se conhece sobre a eficiência da resposta fixadora de N2 de leguminosas arbóreas nativas da Amazônia quando inoculadas com rizóbios específicos ou homólogos, havendo a necessidade de demonstrar o potencial de uso deste inoculante microbiano para estimular tecnologias biológicas na produção agrícola e recuperação de solos. O objetivo deste trabalho foi avaliar o efeito da inoculação com rizóbios sobre o crescimento e distribuição de biomassa em três leguminosas arbóreas nativas. As espécies selecionadas foram: Inga thibaudiana var. thibaudiana, I. nobilis e Erythrina fusca. Dois solos ácidos da terra firme foram avaliados: Latossolo Amarelo coletado sob pastagem e Argissolo Vermelho Amarelo coletado em sistemas agroflorestais. As espécies foram semeadas em areia e transplantadas para sacos com 2 kg de solo e conduzidas no viveiro. Nos dois solos, três formas de suprimento de N foram testadas: testemunha (plantas não inoculadas e sem N-mineral); plantas supridas com 80 kg de N ha-1; e, plantas inoculadas com um coquetel de estirpes de rizóbios da coleção do INPA. Mensalmente avaliou-se o comprimento do caule das plantas. A colheita foi efetuada aos 93 dias para E. fusca e 165 e 151 dias para I. thibaudiana e I. nobilis, determinando-se a distribuição de biomassa seca nas folhas, raízes, caule e nódulos das plantas. O número de nódulos foi contado e efetuado determinações do N-foliar e N-total das plantas. O delineamento experimental foi o inteiramente casualizado, em arranjo fatorial 2 x 3 (solos x formas de suprimento de N), com 9 repetições. A inoculação com rizóbios influenciou o crescimento, partição de biomassa, indicadores de nodulação e absorção de N, havendo diferenças na resposta dependendo da espécie avaliada. O caráter de especificidade ou de promiscuidade na leguminosa arbórea selecionada é determinante na resposta da espécie a inoculação. Todas as espécies de leguminosas arbóreas pesquisadas adaptaram-se melhor ao solo Argissolo comparado ao Latossolo. Demonstrou-se que as estirpes empregadas como inoculante em I. thibaudiana var. thibaudiana formaram processos de fixação de N2 mais eficientes que quando inoculadas em I. nobilis. Para E fusca, considerada de comportamento não específico quanto a compatibilidade com rizóbios nativos a prática da inoculação favoreceu os processos simbióticos em solo Latossolo comparado ao Argissolo. Evidenciou-se que a técnica de inoculação com rizóbios tem potencialidade alternativa para suprimento de nitrogênio para as plantas, comparado a fertilização nitrogenada.
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Drexel, Jan Peter. "Contribution of Nitrogen Fixation to Planktonic Food Webs North of Australia." Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19733.
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Nitrogen fixation is no longer considered to be a minor factor of the nitrogen cycle in oceanic ecosystems. Recent geochemical and biological efforts have led to a significant increase in the estimated input of nitrogen to marine ecosystems by biological fixation, while molecular studies have increased our knowledge of the number and diversity of nitrogen fixers known to be active in the ocean. Although Trichodesmium spp. have long been viewed as the primary marine nitrogen fixers, recent efforts have shown that various members of the picoplankton community are also actively involved in nitrogen fixation. The relative abundance of different nitrogen fixers is an important ecosystem parameter since nitrogen fixers may differ significantly in their physiology, life history and ecology. Here we combine rate measurements and stable isotope natural abundance measurements to constrain the impact of N2 fixation in the waters north of Australia. Samples were collected in the Coral, Arafura, and East Timor Seas, thus spanning three distinct hydrographic regions. Our data show that Trichodesmium has a significant influence on the stable nitrogen isotope ratios of particulate and zooplankton biomass and suggest that Trichodesmium is a significant source of nitrogen for the pelagic ecosystem. Based on stable carbon isotope ratios, it is also likely that the pathways are indirect and nitrogen fixed by Trichodesmium enters the higher trophic levels via decomposition as dissolved organic and inorganic nitrogen. Picocyanobacteria showed high diazotrophic activity at some stations, but unlike Trichodesmium, their N2 fixation rate was not reflected in the stable N isotope ratios of particulate and zooplankton biomass. Our results suggest an important N contribution to biomass by diazotrophs in the Coral Sea, Arafura Sea and East Timor Sea.
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Anderson, Annette. "The effects of acetolactate synthase (ALS) inhibiting herbicides on the growth, yield, nodulation and nitrogen fixation of selected legumes." Title page, contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09pha545.pdf.
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Bibliography: leaves 251-268. The main aim of this thesis is to determine the effects of sulfonylurea residues and in-crop usage of selected ALS-inhibiting herbicides on the growth, yield, nodulation and nitrogen fixation of legumes under alkaline conditions. Reviews literature concerning ALS-inhibiting herbicides, nitrogen fixation and the effects of herbicides on legumes, rhizobia, nodulation and nitrogen fixation; Glasshouse trial investigating the effects of flumetsulam on biomass and nodulation of chickpea; Field trail investigating the effects of sulfonylurea residues and 'in crop' usage of flumetsulam on medic shoot biomass and seed yield and the effects of chlorsulfuron residues and 'in crop' usage of flumetsulam and imazethapyr on chickpea shoot biomass, grain yield and nitrogen fixation; develops methodologies for experiments investigating the effects of ALS-inhibiting herbicides on nodulation of chickpea.
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Cruz, Gielli Vieira. "O quadro de contaminação de frutas, legumes e verduras (FLVs) com resíduos de agrotóxicos no Brasil e as oportunidades emergentes." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/101490.
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A divulgação sobre a existência de resíduos de agrotóxicos em alimentos vem tomando espaço no Brasil, incrementando a parcela de consumidores que procura alimentos mais seguros no mercado. Nesse contexto, os objetivos desta pesquisa foram identificar os segmentos de consumidores mais suscetíveis ao consumo de frutas, legumes e verduras (FLVs) com resíduos de agrotóxicos no Brasil e avaliar como os gestores do setor varejista vêm explorando as oportunidades emergentes relacionadas à dinâmica dessa demanda. Inicialmente, um estudo quantitativo explorou dados de 18 FLVs e de seis categorias de rendimentos familiares, com o objetivo de verificar o consumo de alimentos potencialmente contaminados por resíduos de agrotóxicos, conforme as classes socioeconômicas brasileiras no ano de 2009. Isso se deu a partir de dados de consumo de produtos alimentícios fornecidos pelo IBGE e de resíduos de pesticidas em alimentos publicados pela Anvisa. Aos resultados preliminares, foram acrescentados dados das estratégias do mercado varejista na oferta de FLVs mais inócuos. Para essa etapa, foi utilizada uma metodologia de pesquisa do tipo qualitativa, na qual 10 especialistas no tema de pesquisa foram questionados sobre como esse setor explora o mercado de frutas e hortaliças seguras em relação a essa contaminação. Os resultados encontrados na primeira fase do trabalho indicaram que os brasileiros de classes econômicas mais elevadas estão mais expostos ao consumo de resíduos de agrotóxicos presentes em FLVs. Muitas dessas substâncias são potencialmente danosas à saúde, incluindo características carcinogênicas em seus efeitos crônicos. Na segunda etapa, os agentes consultados evidenciaram a predominância da oferta de FLVs orgânicos pelo varejo brasileiro como uma alternativa pertinente, com menor risco de contaminação com resíduos de agrotóxicos. Porém, a ênfase no baixo preço dos alimentos ofertados pode restringir a oferta de FLVs orgânicos. Além disso, houve pouca e nenhuma referência dos especialistas, respectivamente, à certificação de FLVs pelo sistema de produção integrada e ao sistema de agricultura de precisão como alternativas viáveis para a oferta de FLVs seguros em relação a resíduos de agrotóxicos. Esses resultados são contrastantes com o contexto fiscalizador que vem se desenvolvendo sobre o varejo por parte das autoridades, em vista de oferta de alimentos seguros, o que oportunizaria um ambiente favorável à expansão do varejo de FLVs seguros do ponto de vista dos contaminantes agroquímicos.The disclosure of the existence of pesticide residues in food has gained space in Brazil, thus increasing the number of consumers who seek for safer food in the market. In such context, this research aimed at identifying the segments of consumers who are more likely to consume fruits and vegetables with pesticide residues in Brazil, and assessing the way that retail managers have explored the opportunities emerging from such demand. A quantitative study initially surveyed data about 18 fruits and vegetables and six categories of family income, aiming at verifying the consumption of food partially contaminated with pesticide residues, according to the Brazilian socioeconomic classification in 2009. This was based on both IBGE data about food consumption and Anvisa data about pesticide residues found in food. Data about retail strategies to offer more innocuous fruits and vegetables were then added to those preliminary results. At this stage, a qualitative methodology was adopted, and 10 experts were questioned about the ways that this sector has explored the market of safe fruits and vegetables considering such contamination. The results found in the first phase of this work pointed out that upper class Brazilians have been more exposed to the consumption of pesticide residues in fruits and vegetables. A number of such chemicals are potentially harmful to health, including carcinogenic characteristics among their chronic effects. At the second stage, the agents consulted evidenced the prevalence of the offer of organic fruits and vegetables by the Brazilian retail industry as a pertinent alternative, with lower risk of contamination with pesticide residues. However, the emphasis on the low price of food may limit the offer of organic fruits and vegetables. Furthermore, there was little and none reference by the experts concerning fruit and vegetable certification provided, respectively, by the integrated production system and the precision agriculture system as viable alternatives to offering safe fruits and vegetables in terms of pesticides residues. Such results are in contrast to the control that has been developed by authorities over retail to offer safe food, which would favor the expansion of safe fruit and vegetable retail regarding chemical contaminants.
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Couedel, Antoine. "Analysis of performances of crucifers-legumes cover crop mixtures to provide multiple-ecosystem services." Thesis, Toulouse, INPT, 2018. http://www.theses.fr/2018INPT0097/document.
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Les cultures intermédiaires multi-services (CIMS) implantées en interculture entre deux cultures de rente permettent de produire de nombreux services écosystémiques. Parmi les familles d’espèces utilisées comme CIMS, les crucifères réduisent efficacement la lixiviation de nitrate et de sulfate en captant l’azote (N) et le soufre (S) minéral du sol (services de piège à N et à S). Les crucifères ont aussi la capacité de contrôler les pathogènes via des composés biocides issus de l’hydrolyse de métabolites secondaires appelés glucosinolates (GSL). L’objectif de nos travaux de recherche est d’évaluer les performances en termes de services écosystémiques liés à l’azote, au soufre et au potentiel de bio-contrôle d’une grande diversité de mélanges bispécifiques de crucifères et de légumineuses en comparaison aux CIMS pures. Nous avons réalisé des expérimentations sur 2 sites contrastés (région de Toulouse et Orléans, France) et sur 2 années pour tester les performances de mélanges crucifère-légumineuse en comparaison aux espèces pures. Les espèces testées sont i) pour les crucifères : colza, moutarde blanche, moutarde brune, moutarde éthiopienne, navet, navette, radis, roquette, et ii) pour les légumineuses : trèfle Egyptien, trèfle incarnat, vesce commune, vesce pourpre, vesce velue, pois, soja, féverole et lupin blanc. Nos travaux de recherche montrent que les mélanges crucifère-légumineuse peuvent produire simultanément divers services écosystémiques avec un haut niveau d’expression, allant de 2/3 (production de GSL, engrais vert à N et S), à quasiment 100% (piège à N et S) du service produit par la famille d’espèce pure la plus performante. La concentration et les types de GSL ne changeant pas en mélanges, les interactions des crucifères avec leurs pathogènes restent identiques. Via une revue de littérature nous concluons également que le service de bio-contrôle des cultures pures de crucifères peut être maintenu en mélanges crucifère-légumineuse sur une grande diversité de pathogènes et adventices tout en réduisant les potentiels dis-services sur les auxiliaires et sur le cycle de l’azoteMulti-services cover crops (MSCC) grown during fallow period between two cash crops provide various ecosystem services. Among species used as MSCC, crucifers can efficiently prevent nitrate and sulphate leaching by catching residual soil mineral nitrogen (N) and sulphur (S) afterthe preceding cash crop (N and S catch crop services). Crucifers also have a unique capacity to suppress pathogens due to the biocidal hydrolysis products of endogenous secondary metabolites called glucosinolates (GSL). The aim of our study was to assess the provision of various ecosystem services linked to N, S cycles and biocontrol potential for a wide range of bispecific crucifer-legume mixtures in comparison to sole cover crops of legume and crucifer. We carried out experiments in 2 contrasted sites (Toulouse and Orléans regions, France) during 2 years in order to assess these services and the compatibility of various bi-specific crucifer-legume mixtures. We tested a great diversity of species, such as i) crucifers : rape, white mustard, Indian mustard, Ethiopian mustard, turnip, turnip rape, radish and rocket, and ii) legumes: Egyptian clover, crimson clover, common vetch, purple vetch, hairy vetch, pea, soya bean, faba bean, and white lupin. Our study demonstrated that crucifer-legume mixtures can provide and mutualize various ecosystem services by reaching from 2 thirds (GSL production, S and N green manure) to the same level ofservice (N and S catch crop) than the best sole family of species. GSL profile and concentration did not change in mixtures meaning that crucifer-pests interactions were identical. Through a literature review we also illustrated that biocontrol services of crucifers could be largely maintained in crucifer-legume mixtures for a wide range of pathogens and weeds while reducing potential disservices on beneficials and increasing N related service
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Duernberger, Kimberley. "Tracing nitrogen through the food chain in an urbanized tidal creek." View electronic thesis (PDF), 2009. http://dl.uncw.edu/etd/2009-1/r3/duernbergerk/kimberleyduernberger.pdf.
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Wang, Xuan. "Nitrogen conservation by struvite formation during composting process with food wastes." HKBU Institutional Repository, 2015. https://repository.hkbu.edu.hk/etd_oa/201.
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Food waste as a dominant fraction of municipal solid waste was in most of cases buried in landfills creating a burden on big cities with large populations such as Hong Kong. Composting provided an environmentally viable technology to divert food waste to resource utilization for the production of valuable organic fertilizer. The main problem associated with food waste composting was the intensive acidification prior the commencement of the composting process, which is commonly adjusted by the addition of alkaline materials such as lime. However, more than 50% of the initial nitrogen will be lost as ammonia, which not just reduces the nutrient value of the compost but also leads to serious odour generation. Therefore the objective of this study was to develop means to reduce the nitrogen loss through struvite formation. The first experiment of this research investigated the feasibility of controlling the nitrogen loss through struvite formation during food waste composting. Struvite forms when magnesium (Mg), phosphorus (P) and nitrogen (N) salts exist in equimolar ratio at a slightly alkaline pH. Thus to fix the ammonia, MgO and K2HPO4 were added to food waste indifferent molar ratios (P1, 0.05M/kg MgO and 0.05M/kg K2HPO4; P2, 0.05M/kg MgO and 0.1M/kg K2HPO4) to induce struvite formation that can fix the compost-borne ammonia during composting. The pH of the composting mass of P1 was below 5 for more than one. However, the pH of P2 was controlled in a narrow range from 6.8 to 8.7. This slightly alkaline pH ensured a good microbial activity and improved the degradation rate as well as the precipitation of struvite. In treatment P2, the formation of struvite effectively reduced the nitrogen loss from 40.8% to 23.3% when compared to treatment with lime amendment. However, electrical conductivity (EC) of the compost increased to 6.4 mS/cm due to the addition of Mg and P salts. High salinity of the compost retarded seed germination which required further investigation to reduce the salinity while maintaining good nitrogen removal. To overcome this issue, lime as the more effective alkaline amendment, was supplemented in different concentrations along with struvite salts (to P1 treatment having less Mg salt that could reduce the salinity) to alleviate the low pH and struvite formation. The pH of the composting masses were effectively increased with increasing lime dosages and 2.25% lime was sufficient to maintain the pH in alkaline condition that significantly improved the degradation of active organic compounds resulting in increased dissolved organic carbon (DOC) and soluble organic nitrogen (SON) contents. With 2.25% lime and struvite salts, ammonia emission was significantly reduced from 44.3 to 27.4% through struvite formation compared with lime alone treatment. Furthermore, the EC were also decreased from 5.21to 3.40 mS/cm when lime amendment rate increased from 0.75% to 3%. However, the ammonia emission increased with an increase in lime dosage. Interfering ions such as calcium and potassium were reported to affect the struvite formation and pH control. Therefore, in the subsequent experiment, the influence of different types of P salts was investigated to reduce the salinity as well as N loss. When K2HPO4, Na2HPO4 and H3PO4 were used as the supplementary P salts, there were no significant differences on nitrogen conservation. In addition, the results indicated that K+ and Na+ were attached on the surface of struvite rather than constituted the crystal structure. Compared with other P salts, the presence of K+ in K2HPO4 also made a contribution to total nutrient content that benefited the final product. When CaO was gradually substituted with MgO as pH amendment, ammonia emission was significantly reduced implying that Ca2+ ions would influence the struvite formation, either by competing for phosphate ions or by interfering with the crystallization. However, this negative effect could be ignored when the Ca2+/Mg2+ ratio was below 1:2. Considering the cost of MgO, supplementation of Ca2+/Mg2+ ratio at 1:2 (0.15M CaO and 0.3M MgO) with 0.05M K2HPO4 was identified as the optimum conditions (Treatment M0.3) that effectively reduced the nitrogen loss to 28% in contrast to 46% with lime addition. The significant reduction of ammonia emission through struvite formation was observed with the optimum condition that the odour unit (OU) of ammonia emission was reduced to 1.8×104 when compared with lime treatment (3.0×104) indicating a significant reduction of OIMAX (maximum odour index). Meanwhile, the well-controlled pH of this technology ensured the effective decomposition of organic matter that significantly reduced the emission of volatile fatty acids (VFAs) also. The population of total bacteria was also improved due to the addition of phosphate salts. The total nutrient content of struvite composts of treatment with optimum condition (M0.3) was 4.14% (1.5% N, 0.44% P and 2.2% K) that was higher than normal lime treated compost 2.92% (1.3% N, 0.34% P and 1.28% K). In pot experiment, soil was amended with composts at 0, 2.5%, 5% or 10% (w/w dry wt. basis). At the same application rate, the biomass yields of Chinese cabbage and cherry tomato plants were improved by struvite compost when compared tonormal compost. Considering the increasing salinity of soil with high application rate, the optimum dosage of 5% struvite compost is recommended. To conclude, a food waste composting technology was developed to achieve good nitrogen conservation and decomposition that alleviated odour issue and produced compost with higher nutrient contents, which increased its application value
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Carlsson, Georg. "Input of nitrogen from N2 fixation to northern grasslands /." Umeå : Dept. of Agricultural Research for Northern Sweden, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/200576.pdf.
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Mmonatau, Yvonne. "Flour from the Morama bean : composition and sensory properties in a Botswana perspective." Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/1692.
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Thesis (Msc Food Sc (Food Science))--University of Stellenbosch, 2005.This study was undertaken in view of the high incidence of malnutrition problems such as protein-energy malnutrition and diabetes type 2 in countries like Botswana, and due to worldwide interest in underutilised and underdeveloped crops. Morama bean, the seed of Tylosema esculentum (family Fabacae), occurs naturally in the drier areas of Southern Africa, including Botswana, where it is, to a small extent, harvested as wild plant for human consumption. Due to the potential of this crop there is increasing interest in its cultivation. Despite its traditional use as food source in Botswana, little is known about its nutritional value, benefits and disadvantages, and its use as food was therefore the reason for this research. A specific aim was to improve the school feeding programme with this readily available indigenous product.
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Melim, Ema Margarida Gonçalves. "Achieving a planetary health diet: red meat and legumes availability in Portugal." Bachelor's thesis, [s.n.], 2019. http://hdl.handle.net/10284/8520.
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Trabalho Complementar apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Licenciada em Ciências da NutriçãoAims: The global food system has strong implications in the depletion of natural resources, biodiversity loss, greenhouse gas emissions and climate change. To face the current challenges, a planetary health diet was recently proposed by the EAT-Lancet Commission, serving as a guide to the implementation of diets aligned with the environmental boundaries of the planet. The aim of this paper is to compare the planetary health diet recommendations with the current consumption of legumes and red meat in Portugal, exploring different policy strategies that promote healthy and environmentally sustainable eating patterns in the country. Methods: Data from the Food and Agriculture Organization’s Food Balance Sheets regarding legumes and red meat supply was used, as well as Statistics Portugal data for production and consumption of red meat, and National Food, Nutrition and Physical Activity Survey concerning consumption of both legumes and red meat. Results: The national consumption of red meat is four times above (68g/day) the recommendations for a healthy and sustainable diet while legumes consumption is three times below (24g/day) what is recommended, reflecting a nutritional transition to a westernized food pattern, both unhealthy and unsustainable. Conclusions: Integrated policies that promote increased information and awareness regarding sustainable diets and effective changes in the food environment that facilitate sustainable food choices by consumers are essential to support a dietary shift in the country towards plant-based diets aligned with the planetary boundaries and sustainable development goals.
Objetivos: O sistema alimentar global tem fortes implicações na degradação ambiental do planeta e alterações climáticas. Recentemente, foi proposta uma dieta de saúde planetária pela EAT-Lancet Commission que serve de referência para a promoção de padrões alimentares alinhados com os limites ambientais do planeta. O objetivo deste estudo é analisar o consumo de leguminosas e de carne vermelha em Portugal no âmbito da recente referência planetária, explorando possíveis estratégias políticas que promovam a transição para uma alimentação ambientalmente mais sustentável no país. Metodologias: Foram utilizados dados das Balanças Alimentares da Food and Agriculture Organization relativos à disponibilidade de leguminosas e carne vermelha, dados estatísticos do Instituto Nacional de Estatística sobre produção e consumo de carne vermelha, e dados do Inquérito Alimentar Nacional e de Atividade Física relativamente ao consumo de leguminosas e carne vermelha. Resultados: O consumo nacional de carne vermelha encontra-se aproximadamente quatro vezes acima (68g/d) das recomendações para uma dieta de saúde planetária enquanto que o consumo de leguminosas se encontra três vezes abaixo (24g/d) do recomendado, refletindo uma transição nutricional para um padrão alimentar mais ocidentalizado, pouco saudável e insustentável. Conclusões: Políticas integradas que promovam a informação e a sensibilização para uma alimentação sustentável e a modificação do ambiente alimentar que facilite escolhas mais sustentáveis pelos consumidores são essenciais para que o padrão alimentar em Portugal se aproxime da dieta planetária, contribuindo ainda para os objetivos de desenvolvimento sustentável e alterações climáticas.
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Lima, Ana Lucia da Silva. "Relação entre longevidade foliar, nitrogenio e compostos secundarios em folhas de leguminosas arboreas." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/315373.
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Orientadores: Marlene Aparecida Schiavinato, Claudia Baptista HaddadTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-09-11T21:06:20Z (GMT). No. of bitstreams: 1 Lima_AnaLuciadaSilva_D.pdf: 355483 bytes, checksum: 9ce9e116731fc53ab23c70ac20c5cf48 (MD5) Previous issue date: 2005
Resumo: A duração do ciclo de vida foliar determina características distintas nas folhas, que são relevantes para a sobrevivência da planta em diferentes habitats. Tem sido verificado que as espécies perenifólias apresentam mecanismos mais eficientes de conservação de nitrogênio (N) em relação às espécies decíduas. Esses mecanismos são: eficiência de reaproveitamento de nitrogênio (ERN), proficiência de reaproveitamento de nitrogênio (PRN) e eficiência do uso de nitrogênio (EUN). Segundo um dos paradigmas da ecologia vegetal, as espécies crescendo em ambientes oligotróficos têm maior eficiência de reaproveitamento de nutrientes em relação a espécies características de ambientes eutróficos. A PRN em espécies adaptadas a solos poço férteis é maior do que a de espécies de solos mais férteis. Plantas com longo ciclo de vida foliar possuem maior EUN do que plantas com folhas menos longevas e esta eficiência aumenta com o decréscimo da concentração de nutriente no solo. Espécies perenifólias apresentam maior longevidade foliar do que as decíduas e maior concentração de fenóis. Por outro lado, a concentração de taninos costuma ser maior nas folhas de espécies decíduas. É visto também que as espécies com folhas mais longevas possuem menor concentração de N total, menor concentração de compostos nitrogenados e maior massa foliar específica (MFE). O objetivo deste trabalho foi verificar se as observações encontradas na literatura, comparando espécies perenifólias e decíduas, aplicam-se também às espécies semidecíduas (Hymenaea courbaril - sem FSN e Lonchocarpus guilleminianus ¿ com FSN) e decíduas (Enterolobium contortisiliquum ¿ com FSN e Peltophorum dubium - sem FSN) encontrada em uma Mata Estacional Semidecídua remanescente da Mata Atlântica. As plantas foram cultivadas em casa de vegetação, em vasos contendo solo de local onde as espécies são encontradas na mata, enriquecido ou não com N. Plantas de H. courbaril e P. dubium também foram cultivadas em areia. Houve decréscimo na concentração de clorofila total com o avanço da idade foliar nas quatro espécies. As ERN, PRN e EUN decresceram com o aumento da concentração de N no solo. Espécies com FSN apresentaram menor ERN, PRN e EUN em relação às espécies sem FSN. Plantas cultivadas em areia tiveram maiores ERN, PRN e EUN. Os resultados mostraram uma relação inversa entre os parâmetros de ERN, PRN, EUN e presença de FSN e fertilidade do solo. Os resultados obtidos corroboram os da literatura, já que as espécies com folhas mais longevas apresentaram concentrações maiores de fenóis e maior MFE, menores de taninos, nitrato, proteínas, aminoácidos, clorofila e N total
Abstract: Depending on the leaf life span, the leaves show distinct characteristics, which are relevant to the survival of the plant in different habitats. It has been noticed that the evergreen species show more efficient mechanisms of Nitrogen (N) conservation. These mechanisms are related to N Resorption Efficiency (NRE), N Resorption Proficiency (NRP) and N Use Efficiency (NUE). According to one of the paradigms of plant ecology, species growing in oligotrophic environments are more efficient in nutrient resorption than species from eutrophic environments. It is well known that the NRP in species adapted to soils which are not very fertile, is higher than in species of fertile soils. Plants with long leaf life span have higher NUE than plants with shorter leaf life span and the NUE increases with the decrease of nutrient in the soil. Since the evergreen species present longer leaf life span than the deciduous, their leaves present higher concentration of phenolic compound. On the other hand, the concentration of tannins is usually higher in leaves of deciduous species. It is also known that the long leaf life species have lower concentration of nitrogen compounds and higher Specific Leaf Mass (SLM). The objective of this study was to verify if the observations found in literature, comparing evergreen species to deciduous species, are also applied to the semi deciduous species (Hymenaea courbaril - without SNF and Lonchocarpus guilleminianus ¿ with SNF) and deciduous species, (Enterolobium contortisiliquum ¿ with SNF and Peltophorum dubium - without SNF) of a semi deciduous tropical forest, remnant of the Atlantic Forest. The plants were grown in a greenhouse; in pots filled with soil from their natural environment, enriched or not with N. Plants of H. courbaril and P. dubium were also grown in sand. The results obtained confirm the observations cited in the literature, since the species with longer leaf life span presented higher SLM and concentrations of phenolic compounds, lower concentrations of tannins, nitrate, total proteins, total free amino acids, chlorophyll total), total N. There was a fall in the concentration of total chlorophyll with the advance of leaf age in the four species. The NRE, NRP and NUE decreased with the increase of N concentration in the soil. Species with SNF presented lower NRE, NRP and NUE if compared to species without SNF
Doutorado
Biologia Vegetal
Doutor em Biologia Vegetal
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Sampson, Helen G. (Helen Grace). "Biomass and protein yields, N2-fixation and N transfer in annual forage legume-barley (Hordeum vulgare L.) cropping systems." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68257.
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In this study, six annual legumes and the perennial, red clover (Trifolium pratense L.) were monocropped (MC) and intercropped (IC) with barley in a field study with three N levels, 0, 30 and 60 kg N ha$ sp{-1}$. At O kg N ha$ sp{-1}$, N$ sb2$-fixation and N transfer were estimated by the $ sp{15}$N isotope dilution (ID) method. At 60 kg N ha$ sp{-1}$, a direct $ sp{15}$N labelling method was employed to study N transfer. The hypotheses were that the annual species would be more productive within one growing season than red clover, that increased N levels would increase herbage dry matter (DM) and crude protein (CP), that the proportion of N derived from N$ sb2$-fixation in IC-legumes would be higher than that of MC-legumes and that within intercrops there would be evidence of N transfer. In neither year was the total DM yield of red clover, MC or IC, less than the rest of the legumes. In 1991, the total DM yield of intercrops responded to 30 kg N ha$ sp{-1}$; in neither year did the estimated total CP yield of MC-legumes or intercrops respond to N levels. Only in 1992 was there evidence of N$ sb2$-fixation and the proportion of N derived from fixation by IC-legumes was 145% higher than that of MC-legumes. Only the $ sp{15}$N direct labelling method gave evidence of N transfer, to associated legume and barley plants in 1991, and to associated legume plants in 1992.
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Salehin, Mohammad. "Molecular and Functional Characterization of Medicago Truncatula Npf17 Gene." Thesis, University of North Texas, 2013. https://digital.library.unt.edu/ark:/67531/metadc407747/.
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Legumes are unique among plants for their ability to fix atmospheric nitrogen with the help of soil bacteria rhizobia. Medicago truncatula is used as a model legume to study different aspects of symbiotic nitrogen fixation. M. truncatula, in association with its symbiotic partner Sinorhizobium meliloti, fix atmospheric nitrogen into ammonia, which the plant uses for amino acid biosynthesis and the bacteria get reduced photosynthate in return. M. truncatula NPF1.7 previously called MtNIP/LATD is required for symbiotic nitrogen fixing root nodule development and for normal root architecture. Mutations in MtNPF1.7 have defects in these processes. MtNPF1.7 encodes a member of the NPF family of transporters. Experimental results showing that MtNPF1.7 functioning as a high-affinity nitrate transporter are its expression restoring chlorate susceptibility to the Arabidopsis chl1-5 mutant and high nitrate transport in Xenopus laevis oocyte system. However, the weakest Mtnip-3 mutant allele also displays high-affinity nitrate transport in X. laevis oocytes and chlorate susceptibility to the Atchl1-5 mutant, suggesting that MtNPF1.7 might have another biochemical function. Experimental evidence shows that MtNPF1.7 also functions in hormone signaling. Constitutive expression of MtNPF1.7 in several species including M. truncatula results in plants with a robust growth phenotype. Using a synthetic auxin reporter, the presence of higher auxin in both the Mtnip-1 mutant and in M. truncatula plants constitutively expressing MtNPF1.7 was observed. Previous experiments showed MtNPF1.7 expression is hormone regulated and the MtNPF1.7 promoter is active in root and nodule meristems and in the vasculature. Two potential binding sites for an auxin response factors (ARFs) were found in the MtNPF1.7 promoter. Chromatin immunoprecipitation-qRT-PCR confirmed MtARF1 binding these sites. Mutating the MtARF1 binding sites increases MtNPF1.7 expression, suggesting a mechanism for auxin repression of MtNPF1.7. Consistent with these results, constitutive expression of an ARF in wild-type plants partially phenocopies Mtnip-1 mutants’ phenotypes.
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Serna-Maza, Alba. "Nitrogen control in source segregated domestic food waste anaerobic digestion using stripping technologies." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/372768/.
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Anaerobic digestion of source segregated domestic food waste (SS-DFW) offers a sustainable management route for reclaiming potential energy in the form of a fuel gas, and nutrients which can be recycled back to land. However, the biochemical characteristics of SS-DFW can lead to free ammonia nitrogen (FAN) concentrations that are inhibitory to the digestion process causing unstable operation and in some cases complete process failure, particularly in thermophilic systems. With the purpose of reducing the total ammoniacal nitrogen (TAN) in the digester, side-stream and in situ biogas stripping technologies were tested. Mesophilic and thermophilic temperatures were evaluated under moderate and complete biogas mixing rates (0.4 l min-1 – 2.6 l min-1) in a batch system. Laboratory investigations showed that TAN reductions in an in situ bubbling reactor with moderate and complete gas mixing rates were non-existent at mesophilic temperatures and minimal at thermophilic temperatures. For this reason, it is unlikely that in situ biogas stripping would be adequate to prevent TAN concentrations greater than 2500 mg N l-1 in a food waste digester and thus will not mitigate ammonia inhibition in a thermophilic system. Semi-continuous trials carried out on SS-DFW in laboratory-scale digesters, fed daily at an organic loading rate (OLR) of 2 kg VS m-3 day-1 and coupled to stripping columns at low bleed rates (2 – 3.5 % digester volume per day treated in the stripping process) were effective in reducing ammonia concentrations to below thermophilic toxic levels (TAN concentration of 2500 – 3500 mg N l-1). The experiments also confirmed that removal of a proportion of the digester contents and their exposure to thermophilic conditions with pH adjustment to 10 had no adverse effects on performance in terms of biogas production (0.83 ± 0.03 l g-1 VS without stripping, 0.84 ± 0.05 l g-1 VS with stripping) or VS destruction (81.8 % without stripping, 88.5 % with stripping). The process required high pH and temperature (≥70 ⁰C) to achieve a TAN concentration below the toxic threshold for thermophilic digestion, and it is unlikely that stripping at 55 ⁰C and pH 10 would achieve the target reduction. The research showed the way forward for the application of side-stream stripping to prevent the build-up of ammonia under thermophilic conditions, if the digester is started up with a non-inhibitory FAN concentration in the inoculum.
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Chaves, Josimar da Silva. "Isolamento, caracterização e eficiência simbiótica de bactérias fixadoras de nitrogênio isoladas de Estilosantes (Stylosanthes ssp.)." Universidade Federal de Roraima, 2014. http://www.bdtd.ufrr.br/tde_busca/arquivo.php?codArquivo=228.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorEntre as leguminosas forrageiras potencialmente importantes para as condições edafoclimaticas do Brasil, o gênero Stylosanthes destaca-se como alternativa para a melhoria da fertilidade do solo em pastagens consorciadas com gramíneas, tanto pela sua adaptação ao sistema quanto pela capacidade de estabelecer simbiose com bactérias fixadoras de nitrogênio. O objetivo deste trabalho foi isolar, caracterizar e avaliar a eficiência na fixação biológica de nitrogênio por bactérias isoladas de nódulos de estilosantes (Stylosanthes ssp.). Foram realizadas coletas de plantas de Stylosanthes ssp. em dois municípios de Roraima (Boa Vista e Bonfim), sendo exsicatas das plantas enviadas para identificação botânica no Museu Integrado de Roraima. As raízes das plantas foram lavadas com água e ao todo 564 nódulos foram coletados e isolados em meio de cultura YMA. Adicionalmente, também foram utilizados no estudo 34 isolados que haviam sido obtidos previamente de Stylosanthes sp. Após a purificação, os isolados foram morfologicamente caracterizados em meio YMA, considerando-se o tempo de crescimento, alteração do pH no meio de cultura, forma e aspecto das colônias e muco. Realizou-se então um agrupamento dos isolados utilizando-se o coeficiente de Jaccard. Em seguida, conduziu-se um experimento pelo período de 20 dias para a autenticação de 89 isolados de rizóbio em experimento de casa de vegetação inoculando-se plantas de feijão-caupi. Os isolados foram selecionados por representarem os grupos morfológicos das bactérias e, também, as espécies de Stylosanthes de onde haviam sido obtidos. Quarenta e quatro isolados que nodularam o feijão-caupi foram posteriormente utilizados para o estudo da eficiência simbiótica em Stylosanthes capitata cv. lavradeiro. Este experimento foi conduzido em casa de vegetação utilizando-se a estirpe BR BR 446 (recomendada para o Stylosanthes) como controle positivo, além de um tratamento nitrogenado (180,75mg / N por semana) e um controle sem inoculação e sem nitrogênio mineral. O plantio foi realizado em potes contendo uma mistura de areia e solo (1:1) autoclavados e semanalmente aplicou-se solução nutritiva e água quando necessário. A coleta foi realizada aos 65 dias após a emergência das plantas e foram avaliados número e massa de nódulos secos, matéria seca da parte aérea e nitrogênio acumulado na parte aérea. Dos 564 nódulos foram obtidos 258 isolados que somados aos demais 34 isolados (anteriormente obtidos) totalizaram 292. Os isolados apresentaram grande diversidade morfológica e foram agrupados em 87 grupos com 70% de similaridade. A maioria dos isolados 46% apresentou característica de crescimento rápido em meio de cultura YMA e apenas 0,7% com crescimento lento. A autenticação indicou que apenas 44 das 89 bactérias testadas formaram nódulos em feijão-caupi, sendo na sua maioria bactérias de crescimento rápido. Isto indica que possa haver especificidade de nodulação entre os isolados de rizóbio e as espécies de estilosantes e diverge da literatura que indica que estilosantes preferencialmente nodula com bactérias de crescimento lento. O experimento de eficiência simbiótica indicou que cerca de 50% dos isolados proporcionaram número de nódulos em Stylosanthes capitata igual à estirpe recomendada e proporcionaram produção de matéria seca da parte aérea com tendência superior ao tratamento nitrogenado e a estirpe recomendada. As estirpes St4A29, StG57, St1A8, StF29 e St6E2-3 apresentaram melhor desempenho e possuem potencial para futuras pesquisas de recomendação de estirpes.
Among potentially important forage legumes for edaphoclimatic conditions in Brazil, the genus Stylosanthes appears as alternative for improving the soil fertility in consortium with grasses, both by the adaptation to the system as well as the ability to establish symbiosis with nitrogen-fixing bacteria. The aim of this study was isolate, characterize and assess the biological nitrogen fixation efficiency of the bacterial isolated from nodules of Stylosanthes ssp. Samplings of Stylosanthes ssp. plants were taken from two municipalities of Roraima State (Boa Vista and Bonfim), and plants exsiccates were sent for botanical identification at Integrated Museum of Roraima. The plants roots were washed with water and a total of 564 nodules were collected and isolated on YMA medium. Additionally, 34 isolates previously obtained from Stylosanthes sp. were also included in the study. After purification, the isolates were morphologically characterized, considering the time to growth, culture medium pH reaction, shape and aspect of the colonies and mucus. A clustering analysis was further performed with the Jaccard index. An authentication experiment was carried on during 20 days in glasshouse with 89 isolates inoculated in cowpea. The isolates were selected based on morphological groups and also Stylosanthes species that they had been isolated. Forty-four isolates that nodulated cowpea were after used for symbiotic efficiency evaluation in Stylosanthes capitata (cv. Lavradeiro). This experiment was performed in glasshouse where it was used the strain BR 446 (indicated for Stylosanthes inoculation) as positive control, besides a treatment with nitrogen (180,75mg / N per week) and a control without inoculation or nitrogen. The sowing was done in pots containing a mixture of sand and soil (1:1) autoclaved. Harvest was done 65 days after plant germination and were evaluated the nodules number and dry mass, plant dry matter and nitrogen accumulation in the dry matter. From 564 nodules, 258 isolated were purified and, with the additional 34 isolates (previously obtained), 292 isolates were consider for the study. The isolates showed high morphological diversity and were clustered in 87 groups, with threshold 70%. Most of the isolates 46% presented fast growing on YMA medium and only 0,7% were slow-growing. The authentication revealed that 44 of the 89 bacteria tested were able to form nodules in cowpea, and most of this isolates were fast-growing. This result indicated that could exist nodulation specificity between rhizobium isolates and Stylosanthes species, and diverge of the previous observations that had indicated Stylosanthes as mainly nodulated by slow-growing bacteria. Symbiotic efficiency experiment indicated that about 50% of the isolates were able to form nodules in Stylosanthes capitata similar to recommend strain and trend to higher contribution for biomass production was observed in comparison with nitrogen treatment and recommended strain as well. The strains St4A29, StG57, St1A8, StF29 and St6E2-3 have shown best performance and have potential for future researches to strains recommendation.