Browsing by Subject "Carbohydrates"
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Item Carbohydrate reserve patterns in honey mesquite during bud-break(Texas Tech University, 1982-05) Seipp, Wayne WilbertHoney mesquite (Prosopis glandulosa var. glandulosa) is a widespread "pest" plant occurring primarily in Texas and other parts of the Southwest. Mesquite growing on the High and Rolling Plains of Texas was sampled during the 1979 and 1980 growing seasons and analyzed for TNC (total nonstructural carbohydrates). Mesquite samples were collected from trees growing on a deep hardland range site on the High Plains and three different range sites (deep hardland, valley and mixedland slopes) in the Rolling Plains to evaluate the effect of soil type on the physiological processes occurring in mesquite. At each sampling date environmental parameters such as soil moisture, soil temperature and air temperature were measured along with a phonological description of each tree sampled. These data were collected to determine if there was a relationship between the environmental parameters and the physiological processes of mesquite. Root, trunk (basal stem), stem (2-year-old growth) twig (previous years growth) and bud samples were collected weekly to determine trends of carbohydrate movement in mesquite during the growing season with particular emphasis on the physiological activity at bud-burst. Mesquite in all plant parts increased in TNC concentration prior to budburst followed by a rapid decrease as plants began to leaf out. Recharge of root carbohydrates began when leaf expansion was near completion and occurred more rapidly than aboveground plant parts. These results indicate that the aboveground storage organs of mesquite are capable of storing and providing energy to emerging buds. The above ground plant parts, particularly stems, twigs and buds, can likely supply energy to growing leaves and flowers more effectively than roots and trunk because of their proximity to the buds. The data from this study confirm root and stem TNC trends reported in other studies and supplement that research by describing physiological activity of buds and twigs at bud-burst.Item Carbohydrate trends in broom snakeweed (Xanthocephalum sarothrae)(Texas Tech University, 1982-05) Alliney, Jorge EBroom snakeweed (Xanthocephalum sarothrae) is a suffretescent shrub widely distributed in the southwestern United States and northern Mexico. This weed is a serious problem in range management since it is toxic and it is a strong competitor with the desirable grasses in the plant community. Therefore, its control is amply justified. Translocation of foliar applied growth regulating herbicides is associated with total nonstructural carbohydrate (TNC) translocation in the plant. Foliar herbicides have to be applied at a time when carbohydrates are translocated throughout the plant to be effective. Therefore, knowledge of TNC trends is fundamental to application of foliar applied herbicides. The study was conducted at two locations in Lea County, New Mexico, on broom snakeweed: (a) to estimate trend of TNC concentration through the year; (b) to correlate TNC to phenological stages; and (c) to evaluate the influence of environmental parameters that affect TNC. Environmental parameters measured included soil water content and soil temperature. Three plant parts: small stems, large stems and roots were analyzed for TNC by the method of acid extraction with .2N HCl and determined by spectrophotometry. The general trend had two peaks and two depressions at Location 2, but a less defined peak in midsummer at Location 1. No particular tissue was more important for storing carbohydrates than others. Snakeweed accumulated TNC during periods when elaboration of carbohydrates exceeded the demand for respiration and growth. Reserves were used for regrowth and for flowering. Soil temperature (30-cm depth) was the environmental parameter most closely associated with TNC.Item Influence of phenology on carbohydrate trends and herbicidal control on silverleaf nightshade (Solanum eleagnifolium Cav.)(Texas Tech University, 1986-08) Stubblefield, Robert ErnestSilverleaf nightshade (Solanum eleagnifolium Cav.) has become an economically important weed in the southern United States and Central Americas. The actively growing weed competes with crops and pastures for the available soil water and nutrients. Occasionally, the closed canopy of heavy infestations makes understory forage unavailable to livestock. In addition, there is the danger of direct poisoning because the plant contains a steroid alkaloid toxic to livestock if consumed in sufficient quantity. This study was conducted in Terry County, Texas, at four locations. Soils of the study site are relatively homogenous and belong to the Amarillo and Portales series. The objectives of this study were to: (1) identify the total nonstructural carbohydrate (TNC) trends in silverleaf nightshade; (2) monitor the influence of irrigation on TNC trends; (3) correlate TNC trends with phenological development; and (4) evaluate the most appropriate time to control silverleaf nightshade with glyphosate [N-(phosphonomethyl) glycine]. Environmental parameters measured monthly were soil water content and soil temperature. The phenological condition of the plant was monitored throughout the study. Knowledge of the relationship of environmental conditions, phenological development, and physiological conditions at time of herbicide application can greatly increase the effectiveness of a herbicide on crop or rangeland infestations.Item Influence of site characteristics and phenology on carbohydrate trends in broom snakeweed (Xanthocephalum sarothrae)(Texas Tech University, 1984-08) Courtney, Ronald WayneThis study was conducted at five locations in Lea County» New Mexico and one in Lubbock, Texas on broom snakeweed. The soils involved in the study ranged from a sandy to a loam. The objectives of this study were three-fold: (1) to estimate the trend of total nonstructural carbohydrate (TNC) concentration throughout the year; (2) to correlate changes in the TNC concentration of snakeweed with phenological stages; and (3) to correlate the infltience of environmental parameters with changes in TNC. Environmental parameters studied included soil temperature, relative himiidity and soil moisture. Phenological stages were also recorded. To increase the effectiveness of herbicides and thus to improve range condition, knowledge of the relationship of environmental conditions at the time of spraying, the phenological development, and the physiological conditions of the plant are fundamental.Item Polysaccharide decoration of complexation hydrogel networks for oral protein delivery(2011-08) Phillips, Margaret Ann; Peppas, Nicholas A., 1948-; Maynard, Jennifer; Roy, Krishnendu; Rylander, H G.; Schmidt, ChristinePolysaccharide-decorated complexation hydrogels were investigated for use as oral insulin delivery systems. Several different polysaccharide modifications of poly(methacrylic acid-grafted-ethylene glycol) hydrogels were developed using dextran and pullulan. Polymerizable groups were added to the polysaccharides, dextran and pullulan, by methacrylation. These macromers were then copolymerized with methacrylic and poly(ethylene glycol) to form P(MAA-g-EG-co-Dextran) and P(MAA-g-EG-co-Pullulan) gels using a UV-initiated free radical polymerization. The synthesis of these materials was confirmed using Fourier transform-infrared spectroscopy. The pH-responsive swelling of these systems was investigated using dynamic and equilibrium swelling measurements. Swelling of polysaccharide-modified hydrogels occurred with increasing pH. In acidic conditions, these materials were in a collapsed state while in neutral conditions these materials were swollen. The ability to load insulin into these hydrogels using was demonstrated with loading efficiencies as high as 88% were observed for P(MAA-g-EG-co-Dextran 6000) hydrogel microparticles. Almost zero release of insulin occurred in acidic conditions while an increase in pH was shown to trigger release. The use of dextran and pullulan-modified complexation hydrogels for oral delivery applications was investigated using in vitro cellular viability assays and mucoadhesion experiments. These systems were shown to cause little cytotoxicity to an intestinal epithelium Caco-2 cell model over a range of concentrations as high as 1 mg/ml. The adherence of polysaccharide-modified hydrogels to reconstitituted mucin gels was quantified with the P(MAA-g-EG-co-Dextran 6000) performing the best. Further evaluation of polysaccharide-modified complexation hydrogels for oral insulin delivery was evaluated through in vitro insulin drug transport studies using a mucus-producing Caco-2/HT29-MTX co-culture model. The results showed that the P(MAA-g-EG-co-Dextran 6000) allowed transport of insulin across the cell monolayers and did not adversely affect the integrity of the epithelial monolayer.