Staff Publications

Staff Publications

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A comprehensive assessment of agriculture in lowlands of south Brazil: characterization and comparison of current and alternative concepts
Theisen, Giovani - \ 2017
University. Promotor(en): Niels Anten, co-promotor(en): Lammert Bastiaans. - Wageningen : Wageningen University - ISBN 9789463436380 - 234
cropping systems - farming systems - crop management - lowland areas - wetlands - pampas - brazil - intensification - sustainability - productivity - indicators - soil management - rice - flooded rice - oryza sativa - maize - zea mays - glycine max - cover crops - livestock - rotation - mixed farming - seedbed preparation - farm machinery - teeltsystemen - bedrijfssystemen - gewasteelt - laaglandgebieden - pampa's - brazilië - intensivering - duurzaamheid (sustainability) - productiviteit - indicatoren - bodembeheer - rijst - natte rijst - maïs - dekgewassen - vee - rotatie - gemengde landbouw - zaaibedbereiding - landbouwwerktuigen

Agriculture in the lowlands of south Brazil is of strategic importance at the national level, since it supplies around 80% of the rice consumed by the Brazilian population. In Rio Grande do Sul, the southernmost state in Brazil, three million hectares of lowlands are ready for grain-based agriculture. Of this area, about half is fallow, partly used for cattle grazing, and irrigated rice is the predominant crop, cultivated annually on 1.1 million ha. The remaining area is used for soybean and other crops. The predominant cropping system is a combination of irrigated rice and cattle. Over the last decades, rice yields have steadily increased, but this rise in yield level has to a large extent been obtained at the expense of a continuously higher use of external inputs. The recent introduction of soybean in rotation with rice has partially improved the system, but in most areas the situation is becoming incompatible with the modern demands for sustainability. This thesis presents a long-term study (2006-2015) of five cropping systems for lowlands. Next to monocrop rice and two rice-soybean rotations conducted in either conventional or minimum tillage, the experiment contained two novel systems based on large ridges, on which soybean and maize were combined with either cover crops or crop-livestock integration in winter. In these last systems, 8-m-wide ridges were built to avoid flooding, thus allowing for diversification of cash crops and the cultivation of cover crops or pastures in winter time, as well as the use of no-tillage. All systems were evaluated at process-level, including soil preparation, seeding, plant nutrition, pest management, irrigation, harvesting, transport and cattle management, as well as regarding their performance for the different dimensions of sustainability, particularly environment, land productivity, economics, energy-use and labour. Next to system assessment, two additional experiments were conducted for the evaluation of two specific technologies for soil management in these areas. Crop livestock integration on the ridge-based system offered the best balance between food production, environmental impact and economics. This system is well suited to be used in fields that are kept fallow, thereby enlarging the agricultural productivity of the lowlands. The additional experiments revealed that a knife-roller can successfully substitute plough-and-harrow for soil preparation after rice harvest, and that germination of weed seeds can be reduced if crop seeding is conducted at a lower speed or using a no-tillage seeder equipped with an improved cutting mechanism. Overall the results show that by using alternative cropping systems that allow for diversification and new methods of field management it is possible to simultaneously attain a larger agricultural production and improved sustainability in the lowlands.

Estrogenicity and metabolism of prenylated flavonoids and isoflavonoids
Schans, M.G.M. van de - \ 2015
University. Promotor(en): Harry Gruppen, co-promotor(en): Jean-Paul Vincken; Toine Bovee. - Wageningen : Wageningen University - ISBN 9789462574748 - 180
flavonoïden - isoflavonoïden - glycine max - sojabonen - oestrogeenreceptoren - zoethout - glycyrrhiza glabra - in vitro - flavonoids - isoflavonoids - soyabeans - oestrogen receptors - liquorice

Binding of (prenylated) flavonoids and isoflavonoids to the human estrogen receptors (hERs) might result in beneficial health effects in vivo. To understand structure-activity relationships of prenylated (iso)flavonoids towards the hERs, prenylated (iso)flavonoids were purified from extracts of licorice roots and elicited soybean seedlings. It was observed that prenylation can modulate estrogenicity. Unprenylated, chain and δ-position pyran prenylated (iso)flavonoids show an agonistic mode of action, whereas α/β-position pyran, α/β-position furan and double chain prenylated (iso)flavonoids show an antagonistic mode of action towards hERα in the yeast bioassay. The mode of estrogenic action of prenylated (iso)flavonoids could be related to structural features of the hER. In particular, the increase in length of α/β-position pyran prenylated compounds was related to indirect antagonism. It was also shown that heat and acid affected the stability of 6a-hydroxy-pterocarpans, converting them into their respective 6a,11a-pterocarpenes and consequently modulate their estrogenicity. Six prenylated isoflavonoids acted as SERMs and eight prenylated isoflavonoids showed ER subtype-selective behavior. The kind of prenylation (chain, furan or pyran) was most important for determining SERM activity, whereas additionally the backbone structure, i.e. the presence of an additional D-ring, was of importance for determining ER subtype-selectivity. To determine structure-metabolism relationships, in vitro conversion of purified prenylated (iso)flavonoids by liver enzymes was studied. These compounds can be extensively metabolized by phase I and II enzymes. A glucuronidation yield between 70-80% was observed. It was also shown that pyran and chain prenylation gave more complex hydroxylation patterns with 4 or more than 6 hydroxyl isomers, respectively, compared to unprenylated compounds (only 1 hydroxyl isomer).

Induction of prenylated isoflavonoids and stilbenoids in legumes
Aisyah, S. - \ 2015
University. Promotor(en): Harry Gruppen, co-promotor(en): Jean-Paul Vincken. - Wageningen : Wageningen University - ISBN 9789462574816 - 154
flavonoïden - stilbenoïden - isoflavonoïden - peulgewassen - glycine max - sojabonen - arachis hypogaea - fylogenetica - phaseolus - lupinus - rhizopus - aspergillus - kwantitatieve analyse - flavonoids - stilbenoids - isoflavonoids - legumes - soyabeans - phylogenetics - quantitative analysis

The germination of legume seeds in the presence or absence of stress factors was studied with respect to compositional changes in prenylated isoflavonoids and stilbenoids. Different strategies were applied using (i) different types of legume seed, (ii) different stress factors i.e. biotic, abiotic and their combination, and (iii) different time point of application of the fungus. Mass spectrometric tools to better characterize the position of prenyl groups in the molecules were optimized. Isoflavonoids and stilbenoids appeared more inducible than flavonoids. Fungus was a more effective stress factor than light and wounding. The impact of fungus might be enhanced by combining it with other stress factors; the combination of fungus and light was more promising than that of fungus and wounding. The seeds of various legume species appeared to respond differently towards elicitation by Rhizopus during germination. The kind of molecules induced followed the phylogenetic relationship of the various species, but their amounts induced during germination, alone or combined with elicitation, did not. In terms of quantities of compounds induced, some species such as Glycine max, Phaseolus spp., Lupinus spp. and Arachis hypogaea were more promising than Vigna spp., Lablab purpureus and Psophocarpus tetragonolobus. Moreover, the fact that Rhizopus and Aspergillus could metabolize the stilbenoids induced during the process of simultaneous germination and elicitation of peanut seedlings showed that the type of fungus was a crucial parameter for optimizing accumulation of potentially bioactive compounds.

Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns
Sagrilo, E. - \ 2014
University. Promotor(en): Thomas Kuijper; Ellis Hoffland. - Wageningen : Wageningen University - ISBN 9789462571679 - 128
organisch bodemmateriaal - grondverbeteraars - koolstofvastlegging in de bodem - vesiculair-arbusculaire mycorrhizae - bodemvruchtbaarheid - glycine max - biochar - stikstoffixatie - kooldioxide - emissie - brazilië - soil organic matter - soil amendments - soil carbon sequestration - vesicular arbuscular mycorrhizas - soil fertility - nitrogen fixation - carbon dioxide - emission - brazil

Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns

Edvaldo Sagrilo

Summary

Pyrogenic organic matter (PyOM), also known as biochar, is the product of biomass combustion under low oxygen concentration. There is currently a growing interest in research on the use of PyOM as a soil amendment, inspired by the existence of highly fertile, PyOM-rich anthropogenic soils in the Amazon basin. The presence of PyOM in these so-called Amazonian Dark Earths (ADE) in quantities larger than in the non-anthropogenic surrounding soils is considered one of the main reasons for their high fertility.

Soil additions of PyOM have been suggested to increase soil fertility and crop yields, simultaneously providing additional important environmental services. The offset of CO2 emissions through sequestration of a larger pool of recalcitrant soil organic carbon (SOC) is one of these services. This would at the same time sustain soil microbial activity, which is directly associated to soil quality, for instance, nutrient cycles and plant growth. This multiple win scenario suggests that the addition of PyOM to the soil would be the solution for the “carbon dilemma”. The dilemma states that the main biological benefits from soil organic matter are a consequence of its decay. Therefore, it is unlikely that increased C sequestration and the benefits from its decay can be simultaneously maximized. Rather than win-win, PyOM would then also be subjected to inevitable trade-offs.

Additions of PyOM can modify the turnover rate of native SOC by either accelerating or decelerating its decomposition through a mechanism known as priming. Although positive priming by PyOM has been reported, negative priming has also been found. The higher amount of non-pyrogenic C in ADE, compared to non-anthropogenic surrounding soils has been considered evidence that PyOM can stabilize SOC in the long-term. A complicating issue in studies is that short-term increases in CO2 emission can be due to decomposition of labile PyOM fractions, erroneously suggesting positive priming of SOC. Addition of PyOM can also lead to modifications in the microbial activity and assemblages. Changes in microbial populations can have impacts on their functionality, favouring mutualistic root symbioses such as the arbuscular mycorrhizal fungal (AMF) symbiosis and the rhizobial symbiosis with legumes that is responsible for biological nitrogen fixation (BNF). Although soil amendments with PyOM can stimulate AMF and BNF, results are contrasting and mechanisms are not clear. Most studies of PyOM effects on SOC and on mutualistic root symbioses are from short-term experiments, often conducted in greenhouse or laboratory. Although such studies provide insights in potential factors driving changes in SOC and symbiotic relationships in PyOM-amended soils, they do not assess changes under realistic conditions over periods of time longer that one or a few cropping cycles. Therefore, there is still a gap in our understanding regarding the duration and magnitude of effects over time under field conditions and possible mechanisms involved. This thesis addresses these gaps.

The aim of this research was to provide a better understanding of interactions between PyOM and SOC and the factors controlling symbiotic patterns in a tropical soil amended with PyOM. To reach this aim, I combined greenhouse and field studies. I also used meta-analytic methods in order to quantitatively synthesize data in literature.

In Chapter 2, I combined the results of 46 studies in a meta-analysis. I investigated changes in CO2 emission patterns from an array of PyOM-amended soils and identified the causes of these changes and the possible factors involved. I showed an overall increase of 29% in CO2 emission from PyOM-amended soils. Such increases were only evident in soils amended with a PyOM-C (PyC):SOC ratio >2. These data are consistent with the hypothesis that increased CO2 emission after PyOM addition is additive and mainly derived from PyOM’s labile C fractions rather than from SOC. Therefore, positive priming is not a main driver of increases in CO2 emission in PyOM-amended soils. This PyC:SOC ratio provided the best predictor of increases in CO2 production after PyOM addition to soil. This meta-analysis indicates (i) the importance of taking into account the amount of applied PyC in relation to SOC for designing future decomposition experiments and that (ii) the recalcitrance of PyOM in soil-PyOM mixtures may be less than usually assumed.

A technical problem of separating PyOM-induced priming on SOC from other non-additive interactions is the uncertainty regarding the origin of the respired CO2 (whether from SOC or PyOM). This issue can only be solved with the use of isotopes. In a field study (Chapter 3), I quantified changes in the PyOM and SOC stocks over four soybean cropping cycles (CC) in a sandy Ferralsol, previously supporting a vegetation with C4 plants, amended with different rates of PyOM (0, 5, 10, 20 and 40 Mg ha-1). The PyOM was produced from C3 woody species using traditional pyrolysis methods employed in Northeast Brazil. I used 13C isotopic analysis to discriminate the origin of the C in the soil and quantify the decomposition rates of native SOC and PyOM. I showed that decomposition of traditionally produced PyOM is faster (25-60% within first year) than normally assumed (10-20% within 5-10 years), which was higher than that of native SOC (5-14%). The data indicate preferential decomposition of PyOM compared to native SOC. The intensity of that effect depends on the rate of PyOM applied to the soil. Only on the longer term (>1 yr) addition of PyOM seems to stabilize SOC.

In Chapter 4 I explored mechanisms controlling AMF activity and crop yield in PyOM-amended soils through the use of path analysis. I tested the effects of PyOM rates and P fertilization on soybean root colonization by AMF, soil P and plant performance over four cropping cycles (CCs). Data showed a major effect of CC and P, as well an interaction effect of PyOM x CC on mycorrhizal colonization. There was a linear decrease in root colonization by AMF in CC1 with increasing PyOM rates in contrast to a consistent linear increase in CC4. Plant performance was mainly affected by CC, but a significant interactive effect of PyOM x P was also observed on grain yield. Grain yield was highest at high PyOM rates (20 and 40 Mg ha-1) in the P-fertilized treatments in CC4. Soil pH increased in CC1 with increasing PyOM rates, but no effects were observed in CC4. Path analysis indicated that PyOM effects on root colonization by AMF were not mediated by changes in soil pH or P content. My data are consistent with the hypothesis that interference of PyOM in signalling processes is an important driver of change in AMF activity and that positive effects of PyOM on AMF and crop yield develop with time.

In Chapter 5, I assessed the effects of PyOM application rates and P fertilization on BNF in soybean inoculated with Bradyrhizobium japonicum over four cropping cycles. Again I observed that CC had a significant main effect on most dependent variables, while PyOM was not a significant source of variation. There was a significant PyOM × CC interaction effect on shoot N concentration. In CC1 shoot N concentration after application of 5 Mg PyOM was significantly lower than that of plants grown on plots to which 10 or 20 Mg PyOM was applied. In CC4 shoot N concentration was not affected by PyOM. The major effect of CC was explained through changes in nutrient management, more specifically the addition of micronutrients in CC3 and CC4. Alleviation of micronutrient deficiency increased BNF and also resulted in a positive effect of P on BNF. I conclude that under conditions of adequate management, PyOM application does not improve BNF in soybean.

In Chapter 6 (General Discussion) I synthesize the findings of the previous chapters and use data from additional greenhouse and litterbag field experiments to integrate the results. Data from Chapters 2 and 3 show that if any positive priming occurs due to PyOM addition, it is a small short-term event and does not lead to significant losses of native SOC in the long-term. This was confirmed by data from a 2 yr litterbag experiment, which showed no interaction between decomposition of PyOM and fresh organic matter.

Stability of SOC has been considered an ecosystem property rather than a consequence of recalcitrance, but this definition has not yet been extended to PyOM. In this thesis I demonstrated that stability of PyOM can also be influenced by the soil environment. In order to link PyOM effects to SOC and on root symbioses, I performed path analysis integrating root colonization by AMF, SOC content and Ndfa in one model. We found no significant path coefficients linking AMF and BNF. The model indicated a significant positive path coefficient linking AMF root colonization and SOC in CC4, but not in CC1. The data suggest that PyOM may increase SOC stability through increased AMF activity. Soil aggregation and C sequestration are tightly correlated with abundance of AMF in the soil. I propose that the same mechanism through which AMF stabilizes native SOC may also positively influence PyOM stabilization in the long-term.

In conclusion, I have shown that main beneficial effects of PyOM on AMF and crop yield develop with time, but in well-managed soils increased crop yield is not a direct consequence of increased AMF due to PyOM addition. Finally, although PyOM additions represent an effective form of sequestering C, positive effects of PyOM on crop yield are likely to occur after partial decomposition of PyOM. Therefore, although some benefits of adding PyOM can be simultaneously obtained (C sequestration and increased crop yield), they cannot be simultaneously maximized. This means that the carbon dilemma can only be partially solved by adding PyOM to the soil.

Soja- Glysine Max / Eiwit en oliepad
PPO Akkerbouw, Groene Ruimte en Vollegrondsgroente, - \ 2012
glycine max - sojabonen - voedselgewassen - voedergrassen - olieleverende planten - eiwitbronnen - gewassen - akkerbouw - biobased economy - plantaardig eiwit - soyabeans - food crops - fodder grasses - oil plants - protein sources - crops - arable farming - plant protein
Factsheet van het Eiwit en Oliepad met korte informatie over het gewas soja. Met het project Eiwit & Oliepad wil Innovatief Platteland samen met de gemeente Venray en andere partners het publiek de gelegenheid geven zich een beeld te vormen van de enorme multifunctionaliteit en de nog steeds verder te ontdekken mogelijkheden van in Europa te telen gewassen als grondstof voor de biobased economie
Duurzaamheid van de huidige genetisch gemodificeerde gewassen : effecten van de teelt van genetisch gemodificeerde soja, maïs en katoen op People, Planet en Profit (mens, milieu en economie)
Lotz, L.A.P. ; Breukers, M.L.H. ; Broer, W. ; Bunte, F. ; Dolstra, O. ; Engelbronner-Kolff, F.M. d'; Franke, A.C. ; Montfort, J. ; Nikoloyuk, J. ; Rutten, M.M. ; Smulders, M.J.M. ; Wiel, C.C.M. van de; Zijl, M. van - \ 2011
Wageningen : Plant Research International - 24
gewassen - duurzaamheid (sustainability) - genetisch gemanipuleerde organismen - glycine max - maïs - katoen - koolzaad - zea mays - gossypium hirsutum - brassica napus var. oleifera - transgene planten - crops - sustainability - genetically engineered organisms - maize - cotton - rape - transgenic plants
Deze studie richt zich op genetische modificatie bij gewassen. Wereldwijd werden in 2010 op meer dan 140 miljoen hectare GG-gewassen verbouwd. Dit is ongeveer 70 maal het totale Nederlandse landbouwareaal. Het gaat met name om de handelsgewassen soja, maïs, katoen en koolzaad. Twee GG gewassen zijn ondertussern in de EU toegelaten voor teelt, namelijk maïs dat resistent is tegen bepaalde insecten en een aardappel met een verhoogd zetmeel gehalte.
Sustainability of current GM crop cultivation : Review of people, planet, profit effects of agricultural production of GM crops, based on the cases of soybean, maize, and cotton
Franke, A.C. ; Breukers, M.L.H. ; Broer, W. ; Bunte, F.H.J. ; Dolstra, O. ; Engelbronner-Kolff, F.M. d'; Lotz, L.A.P. ; Montfort, J. ; Nikoloyuk, J. ; Rutten, M.M. ; Smulders, M.J.M. ; Wiel, C.C.M. van de; Zijl, M. - \ 2011
Wageningen : Plant Research International (Report / Plant Research International 386)
transgene planten - gewassen - duurzaamheid (sustainability) - glycine max - sojabonen - zea mays - maïs - gossypium hirsutum - katoen - risicoschatting - akkerbouw - transgenic plants - crops - sustainability - soyabeans - maize - cotton - risk assessment - arable farming
This report adresses the question whether the cultivation of genetically modified (GM) crops abroad for import in the Netherlands, as compared to the cultivation of their conventional (non-GM) counterparts, is in line with Dutch policy and societal aims striving after more sustainable forms of agriculture worldwide and the utilization of the benefits offered by biotechnology in a responsible manner. Three crops were selected as case study objects: sybean, maize and cotton. The sustainability of GM and non-GM crop production was compared with each other based on a review of scientific and other literature. This comparison followed characteristics and criteria associated with the sustainability concept of 'people, planet, profit'.
Het beperken van insectenplagen in gewassen door het aanleggen van barrières rond of in het perceel: een literatuurstudie
Meerburg, B.G. ; Elderson, J. ; Belder, E. den; Alebeek, F.A.N. van - \ 2009
Tilbrug : ZLTO Projecten - 16
geïntegreerde plagenbestrijding - netten - afschermingsmateriaal - barrières - ondergewassen - aphididae - thrips - broccoli - brassica oleracea var. italica - capsicum annuum - vicia faba - glycine max - lupinus - pootaardappelen - slasoorten - uien - functionele biodiversiteit - integrated pest management - nets - screens - barriers - catch crops - seed potatoes - lettuces - onions - functional biodiversity
Veel landbouwgewassen zijn eenjarige teelten in een roulerend bouwplan. Insectenplagen moeten dus elk voorjaar opnieuw hun voorkeursgewassen opsporen en koloniseren. De meeste plaaginsecten bereiken vliegend de nieuwe percelen waar zij een gewas koloniseren. De keuze van plaaginsecten om in een bepaald gewas te landen wordt door een complex van factoren bepaald. In dit document wordt een overzicht gegeven van de literatuur over maatregelen om de verspreiding van plaaginsecten naar nieuwe gewassen of binnen bestaande teelten te beperken. Niet zozeer door landschapselementen, maar door fysieke barrières (biobarrières), het toepassen van vanggewassen, het combineren van twee gewassen. Bij het vaststellen van een effectief maatregelenpakket op het bedrijf zal steeds kritisch gekeken moeten worden naar de (economische en bedrijfsmatige) haalbaarheid van verschillende maatregelen
Research Agenda Setting for the Argentinean Chaco
Nijhof, B.S.J. ; Prieto, D. ; Bindraban, P.S. ; Mansfeld, M.J.M. van; Jongman, R.H.G. ; Querner, E.P. - \ 2008
Wageningen : Alterra (Alterra-report 1617) - 125
landgebruik - glycine max - sojabonen - biobrandstoffen - landbouwontwikkeling - argentinië - land use - soyabeans - biofuels - agricultural development - argentina
Biological nitrogen fixation of soybean in acid soils of Sumatra, Indonesia
Waluyo, S.H. - \ 2000
Agricultural University. Promotor(en): W.M. de Vos; L. 't Mannetje; L.T. An. - S.l. : S.n. - ISBN 9789058082954 - 151
glycine max - sojabonen - bodembiologie - stikstoffixatie - stikstofbindende bacteriën - rhizobium - bradyrhizobium - inoculatie - entstof - biochemische technieken - dna-fingerprinting - stamverschillen - stammen (biologisch) - zaadbehandeling - omhullen - zure gronden - bodemaciditeit - bekalking - sumatra - indonesië - soyabeans - soil biology - nitrogen fixation - nitrogen fixing bacteria - inoculation - inoculum - biochemical techniques - dna fingerprinting - strain differences - strains - seed treatment - pelleting - acid soils - soil acidity - liming - indonesia
<p>The aim of this study is to improve soybean cultivation in transmigration areas, especially in Sitiung, West Sumatra. However, these soils are very acid, and have a high P-fixing capacity. To reduce the amounts of fertilisers, normally 5 - 7 ton lime ha <sup>-1</sup> and 100 kg P as TSP, seed, pelleted with lime (60 kg ha <sup>-1</sup> ) and TSP (10 kg ha <sup>-1</sup> ), was introduced. In this way only 2 ton lime ha <sup>-1</sup> are required.</p><p>Soybean can fix nitrogen (BNF) in symbiosis with ( <em>Brady</em> ) <em>Rhizobium</em> bacteria. However, these acid soils in general, have low numbers of ( <em>Brady</em> ) <em>Rhizobium</em> . By inoculating the soils with ( <em>Brady</em> ) <em>Rhizobium</em> , BNF of soybean, and yield, were considerably improved.</p><p>A study was made of the indigenous ( <em>Brady</em> ) <em>Rhizobium</em> population in view of the following:</p><ul><lem>Although at the beginning the numbers may be low, by repeated soybean cultivation, the numbers will increase, and they may interfere with inoculation of effective ( <em>Brady</em> ) <em>Rhizobium</em> strains.</lem><lem>These indigenous ( <em>Brady</em> ) <em>Rhizobium</em> are adapted to local stress conditions, and they may be useful for the improvement of strains, to be used as inoculants.</lem></ul><p>Using molecular techniques, indigenous strains derived from soil samples from old soybean areas (Java) and from new soybean areas (Sumatra) were classified in more detail. Most likely <em>B. japonicum</em> is the dominant strain in Java while in Sumatra <em>B. elkanii</em> is more present. A <em>Sinorhizobium fredii</em> -like strain was isolated from one soil sample from Java.</p>
Elucidation of the chemical fine structure of polysaccharides from soybean and maize kernel cell walls
Huisman, M.M.H. - \ 2000
Agricultural University. Promotor(en): A.G.J. Voragen; Henk Schols. - S.l. : S.n. - ISBN 9789058081872 - 159
celwanden - polysacchariden - pectinen - galactanen - galacturonzuur - zea mays - glycine max - cell walls - polysaccharides - pectins - galactans - galacturonic acid
<p>The subject of this thesis was the elucidation of the chemical fine structure of polysaccharides from cell walls of soybean and maize kernel. The two species investigated represent different taxonomic groups, soybean belonging to the dicotyledonous and maize to the monocotyledonous plants. Besides representing the most important structures present in cell wall material, these raw materials are of great importance in food and feed industry.<p>The characterisation of the soybean cell wall polysaccharides started with the isolation of the cell wall material as Water-Unextractable Solids (WUS) from soybean meal (chapter 2). The isolation procedure yielded a WUS fraction containing almost all polysaccharides present in the meal and only few other components. WUS was sequentially extracted with chelating agent (Chelating agent Soluble Solids, ChSS), dilute alkali (Dilute Alkali Soluble Solids, DASS), 1 m alkali (1 m Alkali Soluble Solids, 1 MASS) and 4 m alkali (4 m Alkali Soluble Solids, 4 MASS) to leave a cellulose-rich residue (RES). The pectin-rich extracts (ChSS and DASS) were found to have identical sugar compositions and contained predominantly galactose, arabinose, and uronic acid residues. The 1 MASS fraction contained xylose in addition to the former three sugars. The hemicellulose-rich fraction (4 MASS) contained mainly xylose and glucose. No indications were found that ChSS and DASS were structurally different, although it is obvious that their arrangement in the cell wall was not identical.<p>The intact cell wall polysaccharides in the meal and WUS were hardly degradable by enzymes. Once extracted, the polysaccharides from WUS were degraded more easily (chapter 3). The arabinogalactan side chains in the pectin-rich ChSS fraction could to a large extent be removed by the combined action of endo-galactanase, exo-galactanase, endo-arabinanase, and arabinofuranosidase B. The remaining polymer (fraction P) was isolated and represented 30% of the polysaccharides in the ChSS fraction (12% of the polysaccharides in the WUS). This polymer still contained some remaining arabinose and galactose residues, which could not be removed by the enzyme mixture used.<p>The pectic backbone (fraction P) appeared to be resistant to enzymatic degradation by both established (like polygalacturonase) and novel pectic enzymes (like RG-hydrolase). After partial acid hydrolysis of the isolated pectic backbone, one oligomeric and two polymeric populations were obtained by size-exclusion chromatography. Monosaccharide and linkage analyses, enzymatic degradation, and NMR spectroscopy of these two polymeric populations showed that the pectic substances in the original extract (ChSS) contained both rhamnogalacturonan and xylogalacturonan regions, while homogalacturonan was absent (chapter 4). The absence of homogalacturonan distinguishes the pectic substances from soybean from pectic polysaccharides extracted from other sources, which contain homogalacturonan and rhamnogalacturonan regions and can be degraded with polygalacturonase and RG-hydrolase, respectively. Acid hydrolysis of fraction P improves the susceptibility of the remaining polymers for RG hydrolase and exo-galacturonase.<p>The xylogalacturonan present in the ChSS fraction distinguishes itself from xylogalacturonan from other sources known so far. A part of the xylose residues in the xylogalacturonan is substituted with fucose and the xylogalacturonan is resistant to degradation with XGH.<p>The arabinogalactan side chains, which were removed from the ChSS fraction to obtain fraction P, were the subjects of investigation in chapter 5. Fractionation, monosaccharide and linkage analyses, enzymatic degradation, and mass spectrometry of the oligosaccharides in the digest of ChSS after enzymatic digestion with arabinogalactan degrading enzymes indicated the presence of common linear (1,4)-linked galacto-oligosaccharides, and both linear and branched arabino-oligosaccharides. In addition, the results unambiguously showed the presence of oligosaccharides containing (1,4)-linked galactose residues bearing an arabino <em>pyranose</em> residue at the non-reducing terminus, and a mixture of linear oligosaccharides constructed of (1,4)-linked galactose residues interspersed with one <em>internal</em> (1,5)-linked arabinofuranose residue. The presence of an internal arabinofuranose residue in a pectic arabinogalactan chain in cell wall polysacchairdes has not been reported previously, not in soybean, nor in other fruit or vegetable cell walls. Another uncommon feature is the presence of arabinopyranose residues in pectic arabinogalactan.<p>The pectic substances form only one network of the plant cell wall, the other is the cellulose/hemicellulose network. The hemicelluloses were solubilised from the residue with 1 and 4 m KOH solutions (chapter 6). The polysaccharides extracted with 1 m KOH were fractionated by ion-exchange chromatography, yielding a neutral and a pectic population. The sugar composition of the neutral population indicated the presence of xyloglucans and possibly xylans. Enzymatic degradation with endo-xylanases and endo-glucanases showed the presence of xyloglucan fragments only. Analysis of the digest formed after incubation of the neutral population with endo-glucanase V showed the formation of the characteristic poly-XXXG xyloglucan oligomers (XXG, XXXG, XXFG, XLXG, and XLFG), so three out of four glucose residues carry a side chain.<p>In chapter 7, the structural features of glucuronoarabinoxylans from maize kernels are described. First of all, maize kernel cell wall material was isolated as Water-Unextractable Solids (WUS). As expected the non-starch polysaccharides (NSP) had concentrated in the WUS (57%). These NSP were composed mainly of glucose, xylose, arabinose, and glucuronic acid. Sequential extractions with a saturated Ba(OH) <sub>2</sub> -solution (BE1 extract), and distilled water (BE2 extract) were used to solubilise glucuronoarabinoxylans from maize WUS. The glycosidic linkage composition of the extracts and their resistance to endo-xylanase treatment indicated that the extracted glucuronoarabinoxylans were highly substituted. In the maize BE1 extract 25% of the xylose was unsubstituted, 38% was monosubstituted and 15% was disubstituted. The glucuronoarabinoxylans in maize BE1 appeared to be resistant to endo-xylanase treatment, but could be degraded by a sub-fraction of Ultraflo, a commercial enzyme preparation from <em>Humicola insolens</em> . The digest contained a number of series of oligomers: pentose <sub>n</sub> , pentose <sub>n</sub> GlcA, pentose <sub>n</sub> hexose, and pentose <sub>n</sub> GlcA <sub>2</sub> . The presence of these glucuronic acid-containing series of oligomers showed that the glucuronic acids in the glucuronoarabinoxylancan can be very close to each other, but are not distributed blockwise. Finally, a new measure for the degree of substitution of glucuronoarabinoxylans was defined. It turned out that the degree of substitution in maize BE1 is much higher (87%) than in sorghum (70%) and wheat flour BE1 (56%). This indicates that the glucuronoarabinoxylans in maize BE1 are more complex than those in sorghum BE1 and explains their resistance to endo-xylanase treatment.<p>From this research, it can be concluded that both soybean and maize kernel cell wall polysaccharides distinguish themselves in a number of respects from other plant cell walls polysaccharides. The absence of homogalacturonan, but also the presence of internal (1,5)-linked arabinofuranose and terminal arabinopyranose in the pectic arabinogalactan side chains from soybean cell walls and the complexity of the glucuronoarabinoxylan from maize kernel cell walls are discussed in chapter 8. In addition, it was shown that techniques like mass spectrometry and NMR spectroscopy are powerfull techniques to be used after (enzymatic) fragmentation, for chemical characterisation of the original polysaccharides.<br/>
Vaste-stoffermentatie van sojabonen tot tempe.
Reu, J.C. de - \ 1995
Voedingsmiddelentechnologie 28 (1995)9. - ISSN 0042-7934 - p. 11 - 13.
fermentatie - voedselbiotechnologie - glycine max - mucorales - sojabonen - rhizopus microsporus - fermentation - food biotechnology - soyabeans
De bereiding van sojabonen tot tempe met de schimmel Rhizopus oligosporus
vergelijkende opbrengstproef met aardnoten; vergelijkende opbrengstproef met katjang idjo; vergelijkende opbrengstproef met soja; vergelijkend groei-analytisch onderzoek van de rijstcultivar Acorni bij verschillende plantdichtheden
Slobbe, W.G. van - \ 1973
Wageningen : Landbouwhogeschool (Celos rapporten no. 86)
suriname - landbouwkundig onderzoek - onderzoeksprojecten - opbrengsten - aardnoten - vigna radiata - glycine max - cultivars - rijst - plantenontwikkeling - agricultural research - research projects - yields - groundnuts - rice - plant development
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