1,720,974 research outputs found
Figure 11 in Parasenegalia and Pseudosenegalia (Fabaceae): New Genera of the Mimosoideae
No full textFigure 11. Pseudosenegalia riograndensis (Atahuachi & L. Rico) Seigler & Ebinger. —A. Twig with inflorescences and leaves. —B. Fruit. —C. Leaflet, adaxial surface. —D. Flower. —E. Petiolar gland. A–E from Antezana 1325 (NY).Published as part of Seigler, David S., Ebinger, John E., Riggins, Chance W., Terra, Vanessa & Miller, Joseph T., 2017, Parasenegalia and Pseudosenegalia (Fabaceae): New Genera of the Mimosoideae, pp. 180-205 in Novon 25 on page 202, DOI: 10.3417/2015050, http://zenodo.org/record/256146
Characterization of pigments from cultivated Amaranthus species and assessment of their commercial applications as natural food colorants
Get PDFConsumer demands for healthier foods with simple ingredients have evoked trends in the food industry to replace synthetically produced colorants with naturally derived alternatives. Of these, betalain pigments derived from beets (Beta vulgaris L.) serve as an important alternative to the synthetic dye FD&C Red 40 for many different low-acid food applications. Betalains are a versatile class of colorants, but their application can be undesirably expensive due to the limited production areas and high cost of red beets. Vegetable amaranth (Amaranthus spp.) is a particularly appealing alternative to beets because of its high concentrations of betacyanin pigments and status as a ubiquitous low-maintenance crop that is resilient to many of the environmental stresses that afflict traditional crops. Unlike beets, amaranth can be harvested multiple times per season and provide additional chlorophyll and carotenoid pigments from the same plant material. The work herein surveys a diverse collection of vegetable amaranth cultivars for pigment content, color, and composition and also tests their stability in a model beverage system. The highest average betacyanin content was 479 mg per 100g dry tissue from the accession PI 566897 (A. cruentus L.). No betaxanthins were detected in any of the accessions surveyed. The major betacyanin observed in all extracts was amaranthin (betanidin 5-O-β-glucuronosyl-glucoside). Consistent differences in betacyanin profiles were noted between different species. Color values for highly pigmented accessions indicated that amaranth extracts can provide bluer hues than current commerical options derived from beets. The highest total chlorophyll and carotenoid content was observed from accession PI 608661 (A .graecizans L.), with an average of 5123 μg of chlorophylls a+b per gram DT and 819 μg of carotenoids per gram of dry tissue. Five genotypes from this survey noted for their high betacyanin yields and phenotypic differences were grown under field conditions and used as colorants in a model beverage system to evaluate their real-life performance in comparison to current natural colorant options. In this research, the thermal and pH stability of five different amaranth cultivars along with crude and purified beet-sourced colorants were studied. Significant differences in pigment degradation rates and color parameters were observed between amaranth cultivars, with PI 689689 (A. spp.) showing the greatest stability and highest chroma (C*) values. This accession showed similar stability to beet-colored beverages at pH 3 and 4.5 and produced significantly bluer colors. Overall, beverages showed the best stability at the lowest temperature tested (5 °C) and generally had the slowest pigment degradation at a pH value of 4.5. HPLC-MS is currently being used to identify non-betalain extract components that significantly influence extract color and stability. Results indicate that certain Amaranthus cultivars can match the stability of beet-derived colorants and provide color hues unobtainable with beets alone. Overall, the studies described herein supply valuable baseline data that are necessary for understanding betalain biosynthesis in Amaranthus, implementing the use of Amaranthus pigments as natural food colors in a commercial setting, and informing breeding strategies to optimize pigment yield, stability, and color.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2021-12-01The student, Jay Howard, accepted the attached license on 2019-12-12 at 10:04.The student, Jay Howard, submitted this Thesis for approval on 2019-12-12 at 10:11.This Thesis was approved for publication on 2019-12-12 at 11:24.DSpace SAF Submission Ingestion Package generated from Vireo submission #14709 on 2020-02-28 at 17:37:58Made available in DSpace on 2020-03-02T22:38:57Z (GMT). No. of bitstreams: 2
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Previous issue date: 2019-12-12Embargo set by: Seth Robbins for item 114033
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Pseudosenegalia Seigler & Ebinger & Riggins & Terra & Miller 2017, gen. nov.
No full textII. Pseudosenegalia Seigler & Ebinger, gen. nov. TYPE: Acacia feddeana Harms, Repert. Spec. Nov. Regni Veg. 16: 450. 1920 [≡ Pseudosenegalia feddeana (Harms) Seigler & Ebinger]. Shrubs or small trees, some to 12 m; twigs terete or nearly so, not flexuous; short shoots present; prickles and stipular spines absent. Leaves alternate or clustered on short shoots, bipinnate; stipules small, linear, symmetrical, herbaceous, tardily deciduous to persistent; petioles adaxially grooved, 0.5–13 mm long; petiolar gland usually present, sessile, solitary; rachis adaxially grooved, usually with glands between some pairs of pinnae; pinnae 1 to 7 pairs/leaf, opposite; paraphyllidia absent; leaflets 11 to 26 pairs/ pinna, linear, 1.2–2.9 X 0.4–0.9 mm, 1 vein from the base, glabrous to lightly pubescent, midrib subcentral. Inflorescences a cylindrical spike, 1 to 2 clustered in leaf axils. Flowers bracteate, sessile, actinomorphic, sympetalous, 5-merous, with a basal copular nectiferous disk; stamens 1 0 0 to 1 5 0, distinct, attached along the side of the nectariferous disk, exserted; anthers small, dorsifixed, dehiscing vertically, anther glands absent; ovary with a stipe to 2.1 mm long; style filiform; stigma filiform. Legumes straight to slightly curved, flattened to elliptic in cross section, oblong, eglandular, dehiscing along both sutures; seeds uniseriate, not surrounded by pulp, ovoid to ellipsoid, flattened; pleurogram present or absent. Habitat and distribution. Pseudosenegalia is known to occur in dry scrub and thorn-scrub vegetation between 1300 and 3300 m in Bolivia. TAXONOMIC KEY TO SPECIES OF PSEUDOSENEGALIA 1. Leaves with a single pair of pinnae............................. P. feddeana (Harms) Seigler & Ebinger 1 '. Leaves with 3 to 7 pairs of pinnae................. P.riograndensis (Atahuachi & L. Rico) Seigler & EbingerPublished as part of Seigler, David S., Ebinger, John E., Riggins, Chance W., Terra, Vanessa & Miller, Joseph T., 2017, Parasenegalia and Pseudosenegalia (Fabaceae): New Genera of the Mimosoideae, pp. 180-205 in Novon 25 on pages 199-200, DOI: 10.3417/2015050, http://zenodo.org/record/256146
Investigating the potential of novel synergistic postemergence tank mixtures to manage HPPD- and atrazine-resistant Amaranthus tuberculatus populations
Get PDFSubmission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2022-04-06 without embargo termsThe student, Kip Jacobs Jr, accepted the attached license on 2021-10-13 at 15:53.The student, Kip Jacobs Jr, submitted this Thesis for approval on 2021-10-13 at 16:05.This Thesis was approved for publication on 2021-10-19 at 15:26.DSpace SAF Submission Ingestion Package generated from Vireo submission #17160 on 2022-04-06 at 17:08:53Made available in DSpace on 2022-04-29T21:34:08Z (GMT). No. of bitstreams: 2
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Previous issue date: 2021-10-19Chapter 1 includes a literature review of photosystem II-(PSII), phytoene desaturase- (PDS), and 4-hydroxyphenylpyruvate dioxygenase-(HPPD) inhibiting herbicides including their target sites, mode of action and resistance. The Group 5, or PS II-inhibiting herbicides, act by blocking electron transport within PSII in plants. PSII inhibitors compete with plastoquinone (PQ) for the Qb binding site of the D1 protein, causing a unique symptomology that appears on older plant leaves since these herbicides are only xylem mobile and not ion trapped in the phloem. Pigment-inhibiting herbicides, such as the Group 12 herbicides, are commonly used preemergence (PRE) in crops such as cotton, wheat and barley. PDS-inhibiting herbicides directly inhibit the carotenoid portion of the terpenoid pathway. Inhibition of PDS results in the accumulation of phytoene and depletion of carotenoids. Inhibition of the HPPD enzyme by Group 27 herbicides blocks the second step of tyrosine catabolism to PQ, which is important for electron transport in photosynthesis and as an electron acceptor in carotenoid biosynthesis, as well as tocopherols (vitamin E). HPPD inhibitors also indirectly affect the PDS reaction since this enzyme requires PQ as a cofactor.
Waterhemp (Amaranthus tuberculatus) and Palmer amaranth (A. palmeri) are the only two species in the United States that have evolved resistance to HPPD- and PSII-inhibiting herbicides. Waterhemp is a small-seeded, dioecious, summer annual dicot weed species in the Amaranthaceae family and is native to Illinois. Discontinuous germination, C4 photosynthesis, and prolific seed output are some of the characteristics that make waterhemp concerning for growers. Waterhemp has displayed resistance to herbicides from seven different site-of-action groups as a species, including: acetolactate synthase (ALS) inhibitors, 5-enolpyruvyl-shikimate-3-phosphate (EPSPS) inhibitors, protoporphyrinogen oxidase (PPO) inhibitors, synthetic auxins, PSII inhibitors, HPPD inhibitors, and very-long-chain fatty acid (VLCFA) inhibitors. As a result, new herbicide tank mixtures need to be investigated to improve waterhemp management in corn and soybeans.
Chapter 2 describes field experiments conducted at three locations in Illinois and greenhouse experiments with postemergence (POST) tank mixtures containing mesotrione with seed collected from the McLean County resistant site. Field and greenhouse studies were designed to investigate the PDS and PSII-inhibiting herbicides, norflurazon and metribuzin, respectively, as components of two- and three-way POST tank mixtures for managing atrazine- and HPPD-inhibitor-resistant waterhemp. Studies were conducted at two locations (Champaign County, Illinois (CHR), McLean County, Illinois (MCR)) during 2019 and 2020 that contain multiple herbicide-resistant (MHR) waterhemp. Treatments included one of three commercial HPPD-inhibiting herbicides (mesotrione, tembotrione, or topramezone) tank mixed with a reduced rate of metribuzin, norflurazon, or both to investigate the hypothesis of obtaining greater control of MHR waterhemp with two- and three-way tank mixtures compared to the individual active ingredients, and to assess the potential benefit of including norflurazon. Field study results indicated the addition of norflurazon to HPPD-inhibiting herbicides increased waterhemp control (approximately 30%) compared to individual herbicides applied alone. Additionally, metribuzin in combination with HPPD-inhibiting herbicides consistently increased control of MHR waterhemp populations compared to the herbicides applied alone. However, only the three-way tank mixture containing tembotrione at the MCR site reduced biomass relative to two-way treatments containing tembotrione, metribuzin, or norflurazon.
Greenhouse experiments were designed to further characterize the effect of applying norflurazon with metribuzin and a representative HPPD-inhibiting herbicide from the triketone (mesotrione) or pyrazolone (topramezone) subclasses. These experiments indicated a significant reduction in waterhemp biomass when metribuzin was mixed with HPPD inhibitors in comparison to the individual components applied alone. Two-way tank mixtures containing norflurazon resulted in a significant reduction in biomass in combination with mesotrione or metribuzin when compared to the individual active ingredients applied alone. The three-way mixture provided greater control of the SIR population (analogous to MCR) than the two-way treatment of metribuzin and mesotrione. Greenhouse experiments also indicated decreased control, or antagonism, when norflurazon was mixed with topramezone in comparison to topramezone alone. The three-way mixture with topramezone also decreased control in comparison to the two-way combination of metribuzin and topramezone.
Combined results from field and greenhouse experiments demonstrated norflurazon and metribuzin are effective tank-mix partners with HPPD-inhibiting herbicides for control of MHR waterhemp. The addition of a PDS inhibitor to previously studied tank mixtures allowed for a novel expansion of prior research involving HPPD- and PSII-inhibitors, although crop tolerance was not investigated in these experiments. Future research needs to be conducted to further investigate the potential niche of combining these three herbicide classes in tank mixtures in row crop production, such as studying PRE vs. POST applications and herbicide safeners in corn. Varying rate structures (depending on soil texture and organic matter) should also be investigated. Other herbicides (e.g., PPO and VLCFA inhibitors) that provide soil-residual control of waterhemp should be examined as tank-mix partners, as well as other PDS inhibitors (e.g., diflufenican) that may display more activity on waterhemp
Investigation of oxidative stress responses in Amaranthus with colorimetric assays
Get PDFSubmission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2024-12-01The student, James Woods, accepted the attached license on 2022-12-06 at 15:17.The student, James Woods, submitted this Thesis for approval on 2022-12-06 at 16:07.This Thesis was approved for publication on 2022-12-08 at 10:06.DSpace SAF Submission Ingestion Package generated from Vireo submission #18762 on 2023-04-12 at 08:14:14Amaranthus species are paradoxically reviled as “superweeds” and revered as “superfoods.” This distinction is a matter of perspective, but it also reflects a suite of shared biological and adaptive traits among species in the genus. Adaptive traits that define some amaranths as aggressive weeds (e.g., prolific seed output, rapid growth, and high tolerance to abiotic stress) can be reframed as valuable agronomic traits for other amaranths grown as pseudocereals or leafy vegetable crops. Cultivated amaranths are recognized for their high nutritional profiles in both seeds and leaves, which are rich in protein, dietary fiber, flavonoids, and vitamins. Weedy amaranth species are notorious for adaptability to a wide range of agricultural settings and evolving herbicide resistance and thus offer excellent case studies for understanding stress response mechanisms. Amaranths are also highly valued as ornamentals due to the added pigmentation trait, expressed in many visually striking patterns in leaves, stems, and floral tissues. Betalains are the principal source of pigmentation in amaranths and are represented by two main classes: betacyanins (red-magenta colors) and betaxanthins (yellow-orange). Betalain pigments have been implicated in possible antioxidant roles in helping amaranths cope with oxidative stress. Still, questions remain regarding their specific roles among diverse pigmented phenotypes and in concert with other plant enzymatic and non-enzymatic antioxidant systems. Greenhouse and laboratory investigations were thus conducted to assess the effects of two stress treatments (i.e., herbicide and drought) on pigmented and non-pigmented weedy and cultivated Amaranthus species using two commonly used colorimetric assays. Specifically, the thiobarbituric acid reactive substances (TBARS) assay and potassium iodide (KI) assay were used to measure two indicators of oxidative stress, malondialdehyde (MDA) and hydrogen peroxide (H2O2), respectively. Protocol optimizations were made for both assays, specifically focusing on betalain pigments as antioxidants and potentially interfering compounds for these color-based assays. Caveats are discussed for each assay, and recommendations are made regarding how these assays should be implemented and interpreted for amaranths and other betalain-producing plants
Characterization of pigments from cultivated Amaranthus species and assessment of their commercial applications as natural food colorants
No full textConsumer demands for healthier foods with simple ingredients have evoked trends in the food industry to replace synthetically produced colorants with naturally derived alternatives. Of these, betalain pigments derived from beets (Beta vulgaris L.) serve as an important alternative to the synthetic dye FD&C Red 40 for many different low-acid food applications. Betalains are a versatile class of colorants, but their application can be undesirably expensive due to the limited production areas and high cost of red beets. Vegetable amaranth (Amaranthus spp.) is a particularly appealing alternative to beets because of its high concentrations of betacyanin pigments and status as a ubiquitous low-maintenance crop that is resilient to many of the environmental stresses that afflict traditional crops. Unlike beets, amaranth can be harvested multiple times per season and provide additional chlorophyll and carotenoid pigments from the same plant material. The work herein surveys a diverse collection of vegetable amaranth cultivars for pigment content, color, and composition and also tests their stability in a model beverage system. The highest average betacyanin content was 479 mg per 100g dry tissue from the accession PI 566897 (A. cruentus L.). No betaxanthins were detected in any of the accessions surveyed. The major betacyanin observed in all extracts was amaranthin (betanidin 5-O-β-glucuronosyl-glucoside). Consistent differences in betacyanin profiles were noted between different species. Color values for highly pigmented accessions indicated that amaranth extracts can provide bluer hues than current commerical options derived from beets. The highest total chlorophyll and carotenoid content was observed from accession PI 608661 (A .graecizans L.), with an average of 5123 μg of chlorophylls a+b per gram DT and 819 μg of carotenoids per gram of dry tissue. Five genotypes from this survey noted for their high betacyanin yields and phenotypic differences were grown under field conditions and used as colorants in a model beverage system to evaluate their real-life performance in comparison to current natural colorant options. In this research, the thermal and pH stability of five different amaranth cultivars along with crude and purified beet-sourced colorants were studied. Significant differences in pigment degradation rates and color parameters were observed between amaranth cultivars, with PI 689689 (A. spp.) showing the greatest stability and highest chroma (C*) values. This accession showed similar stability to beet-colored beverages at pH 3 and 4.5 and produced significantly bluer colors. Overall, beverages showed the best stability at the lowest temperature tested (5 °C) and generally had the slowest pigment degradation at a pH value of 4.5. HPLC-MS is currently being used to identify non-betalain extract components that significantly influence extract color and stability. Results indicate that certain Amaranthus cultivars can match the stability of beet-derived colorants and provide color hues unobtainable with beets alone. Overall, the studies described herein supply valuable baseline data that are necessary for understanding betalain biosynthesis in Amaranthus, implementing the use of Amaranthus pigments as natural food colors in a commercial setting, and informing breeding strategies to optimize pigment yield, stability, and color.LimitedAuthor requested closed access (OA after 2yrs) in Vireo ETD syste
Microbial shifts following five years of cover cropping and tillage practices in fertile agroecosystems
Get PDFMetagenomics in agricultural research allows for searching for bioindicators of soil health to characterize changes caused by management practices. Cover cropping (CC) improves soil health by mitigating nutrient losses, yet the benefits depend on the tillage system used. Field studies searching for indicator taxa within these systems are scarce and narrow in their scope. Our goal was to identify bioindicators of soil health from microbes that were responsive to CC (three levels) and tillage (chisel tillage, no-till) treatments after five years under field conditions. We used rRNA gene-based analysis via Illumina HiSeq2500 technology with QIIME 2.0 processing to characterize the microbial communities. Our results indicated that CC and tillage differentially changed the relative abundances (RAs) of the copiotrophic and oligotrophic guilds. Corn–soybean rotations with legume–grass CC increased the RA of copiotrophic decomposers more than rotations with grass CC, whereas rotations with only bare fallows favored stress-tolerant oligotrophs, including nitrifiers and denitrifiers. Unlike bacteria, fewer indicator fungi and archaea were detected; fungi were poorly identified, and their responses were inconsistent, while the archaea RA increased under bare fallow treatments. This is primary information that allows for understanding the potential for managing the soil community compositions using cover crops to reduce nutrient losses to the environment.Fil: Kim, Nakian. University of Illinois; Estados UnidosFil: Zabaloy, Maria Celina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Riggins, Chance W.. University of Illinois; Estados UnidosFil: Rodríguez Zas, Sandra. University of Illinois; Estados UnidosFil: Villamil, Maria Bonita. University of Illinois; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Phytochemistry and chemosystematics of Artemisia arctica in Alaska
Get PDFThesis (M.S.) University of Alaska Fairbanks, 2001Artemisia L. (Asteraceae - Anthemideae) is a large and taxonomically complex genus occurring widely throughout the northern hemisphere. Chemical investigations in this genus have mainly been stimulated by the economic and/or medicinal importance of many of its members. This chemical knowledge has also provided useful criteria for resolving systematic uncertainties within the genus. Alaskan Artemisia species are little known chemically despite their historic and contemporary medicinal use. Therefore, an investigation of the chemistry of Alaskan Artemisia arctica was initiated with the dual purpose of searching for structurally novel and/or biologically active compounds and contributing additional criteria for systematic studies of this taxon. Collections of A. arctica from four different geographic locations in Alaska were analyzed for chemical characters and biological activity. The roots and leaves afforded one novel acetylenic isocoumarin, in addition to several known acetylenic and non-acetylenic compounds. The biological and systematic significance of these results are discussed
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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