Seven foliar fertilizers containing calcium were applied to DPL449BR cotton in the Palo Verde Valley on June 24, 2005, immediately after three consecutive days of level one stress. Plants had been blooming prior to application and had several open blooms per plant at time of application. All treatments increased level of leaf chlorophyll by at least 7.4% when compared with the untreated check as with a Minolta 502 SPAD meter on July 7, with greatest (21.3%) increase noted from Calcium Metalosate®. No statistical differences were noted for this parameter on July 13, and by July 21 highest mean leaf chlorophyll content was noted from untreated cotton. Leaf chlorophyll was lowest in untreated cotton on July 25 however. Shortest stigma lengths beyond anthers on July 13 was noted in treatments with highest amounts of calcium applied per acre, while all treatments had numerically fewer abnormal flowers than the untreated check on July 21. Treatments resulted in slightly taller plants than the untreated check on July 6 and 21, and more nodes on July 6. Most treatments also resulted in more fruiting nodes per plant on July 21 and August 4. Greatest height:node ratios were noted in CalMax® treated cotton on all three sample dates. Highest retention percentages were noted in untreated cotton on July 6 and August 4. All treatments resulted in numerically more fruiting structures/plant than the untreated check on July 21, although only CalMax® treated cotton had significantly more. Most treated cotton had fewer such structures per plant on August 4 than on July 21, however such structures in untreated cotton increased during this time. Calcium Metalosate® was the only treatment that resulted in more seed cotton/acre than the untreated check. Calculated lint yields varied, and reflected the single datum turnout percentage for each treatment derived from commercial ginning of modules. Wide variation in turnout data do not appear to be supported with differences in cotton quality data, as similar economics were noted for all cotton lint on a per pound basis.

No description available.

No description available.

Growth hormone binding protein (GHBP) may be an important factor in the regulation of growth as well as an indirect, less invasive way of predicting the status of growth hormone receptors. Several factors (age, nutritional status, sex, and glucocorticoid administration) have been reported to influence circulating growth hormone (GH) levels, growth hormone receptor (GHR) activity and/or GHBP in mammalian species. Therefore, the studies conducted in this research were designed to determine if these factors have any affect on serum GHBP in the young broiler chicken. Serum GHBP activity was expressed as a percent specifically bound ¹²⁵IhGH (%SB), as measured by a dextran-coated charcoal assay. Serum GHBP activity was highest (mean %SB= 14.6 ± 1.2) at hatch aniedecreased linearly (r= -.9516) to 4 wk of age (mean %SB= 4.1 ± 0.6). Sex had no significant affect on serum GHBP activity from hatch to 4 wk of age. Short term nutrient deprivation (24 h fast) of 4 wk old birds had no significant affect on serum GHBP activity, nor did refeeding. Feeding birds nutrient poor diets (low energy, low protein or low energy and low protein) did not significantly affect serum GHBP activity when compared to birds fed a commercial broiler diet. Pulsatile delivery of cortisone acetate (1, 5 and 10 mg/d/b) had no affect on serum GHBP activity at any dose. These results suggest that serum GHBP activity in the chicken is not affected by many factors which do influence GHBP in mammalian species. The lack of response to nutrient deprivation and cortisone acetate may be a factor related to the age of the birds used in these studies. / Graduation date: 1993

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 126-151).

No description available.

No description available.

As the requirements for more efficient and economical crop production emerge, so the need for a better understanding of plant growth and development is felt. It is especially the need to understand means by which man may influence growth and development in order to achieve greater productivity, that requires attention. Observation and analysis of plant growth and the concomitant study of plant components, organs and chemicals, provides one of the research oriented approaches to gaining an understanding of the mechanism of growth control. Ultimately, the extent of reproductive growth (fruiting) or the bearing capacity in all plants is governed by the volume and area of vegetative growth and the supply of substances required for growth produced by those vegetative organs. Productivity then, is governed by the efficiency of conversion of solar energy to chemical energy and by the relative ability to store this energy. Plant shoots play a fundamental role in both assimilation and storage of carbohydrates. Given the same growing conditions, similar plants sometimes exhibit different rates of growth. For example, ontogenetically juvenile plants exhibit differences in form and vigour in comparison with ontogenetically adult plants. Although the genotype of such adult and juvenile plants may vary only in expression and not in constitution, there does appear to be some property in juvenile plants which induces the characteristic enhanced vegetative vigour. It is this property, amongst many others, which needs to be better understood, for it is a potential means of gaining greater yields from plants without alterations being made to the environment. A high degree of organisation of growth processes must exist to account for the orderly development of plants. A few organic compounds that influence certain biochemical and physiological reactions have been isolated from the As the requirements for more efficient and economical crop production emerge, so the need for a better understanding of plant growth and development is felt. It is especially the need to understand means by which man may influence growth and development in order to achieve greater productivity, that requires attention. Observation and analysis of plant growth and the concomitant study of plant components, organs and chemicals, provides one of the research oriented approaches to gaining an understanding of the mechanism of growth control. Ultimately, the extent of reproductive growth (fruiting) or the bearing capacity in all plants is governed by the volume and area of vegetative growth and the supply of substances required for growth produced by those vegetative organs. Productivity then, is governed by the efficiency of conversion of solar energy to chemical energy and by the relative ability to store this energy. Plant shoots playa fundamental role in both assimilation and storage of carbohydrates. Given the same growing conditions, similar plants sometimes exhibit different rates of growth. For example, ontogenetically juvenile plants exhibit differences in form and vigour in comparison with ontogenetically adult plants. Although the genotype of such adult and juvenile plants may vary only in expression and not in constitution, there does appear to be some property in juvenile plants which induces the characteristic enhanced vegetative vigour. It is this property, amongst many others, which needs to be better understood, for it is a potential means of gaining greater yields from plants without alterations being made to the environment. A high degree of organisation of growth processes must exist to account for the orderly development of plants. A few organic compounds that influence certain biochemical and physiological reactions have been isolated from the wide array of organic and inorganic substances found in plant extracts. A growing body of evidence suggests that such growth regulatory compounds are ubiquitous in plants; are active at exceedingly low concentrations and are under genetic control. Plant hormones are almost certainly involved in directing or regulating plant growth and development. The subject of the present research concerns the characterization of differences in shoot growth of juvenile and adult phases of a commercial Citrus cultivar and an investigation of the possible role which plant hormones may play in such differences. In add i tion to a comprehensive literature survey, three separate sets of experiments were conducted. In the first, an analysis of the components and parameters of the difference in vegetative shoot growth of adult and juvenile scions was carried out. Anatomical and ultrastructural comparisons were also made. In the second set of experiments the endogenous levels of gibberellins, cytokini ns and inhibitors of buds and other tissues, which might playa role in the regulation of shoot flush growth, were examined. Specific extractions were performed and appropriate bioassay techniques were employed for the three hormone classes investigated. In the final set of experiments the effects of synthetic plant growth regulators on shoot flush growth were monitored. The growth regulators were applied by means of trunk injections or as droplets on shoot terminal buds. These experiments were planned and executed with the above mentioned concepts and ideals in mind. The objective of the project was to contribute in some measure to the knowledge which will allow better use to be made of available natural resources. / Thesis (Ph.D.)-University of Natal, Pietermartizburg, 1982.

Thesis--University of Wisconsin. / Bibliography: leaves 73-77.

Carotenoids are precursors of hormones and signaling molecules across all kingdoms of life. An increasing body of evidence suggests the presence of yet unidentified carotenoid-derived metabolites (apocarotenoids) with developmental and regulatory functions, besides the known plant hormones abscisic acid (ABA) and strigolactones (SLs). Generally, apocarotenoid synthesis is initiated by carotenoid cleavage dioxygenases (CCDs), which constitute a ubiquitous family of non-heme iron enzymes. In SL biosynthesis, an iron-binding cis/trans-isomerase, DWARF 27 (D27) converts all-trans-β-carotene into 9-cis-β-carotene. This reaction is followed by a double bond cleavage at 9, 10 position, mediated by the stereospecific CCD7. The cis-configured cleavage product of CCD7, 9-cis-β-apo-10’-carotenal, is simultaneously cleaved, triple-oxygenated and rearranged by CCD8, to produce carlactone (CL). CL is a central metabolite and the precursor of a wide range of SLs. The aim of this work is to investigate whether CCD8 synthesize CL-like compounds from other 9-cis-configured apocarotenoids to confirm their presence and synthesis in planta. We showed that CCD8 enzymes from different plants produce a hydroxylated carlactone (3-H-CL) from 9-cis-3-OH-β-apo-10’-carotenal in vitro. In addition, we detected 3-H-CL in Nicotiana benthamiana leaves transiently expressing the CL biosynthesis enzymes from rice and Arabidopsis. 3-H-CL is biologically active, as shown by Striga hermonthica seed germination assay and by its effect on the high-tillering phenotype of the rice d10 mutant. We also confirmed that 3-H-CL is a natural metabolite by detecting it in roots of the rice SL perception mutant d14. In a second project, we investigated the activity of three rice CCDs in vitro and showed that one of them (zaxinone synthase; ZAS) is an apocarotenoid cleavage enzyme with a clear preference for the substrate all-trans-3-OH-β-apo-10’-carotenal, as suggested by a kinetic study. ZAS produces two products, the C18 ketone zaxinone and an unstable C9 dialdehyde that could be identified by LC-MS after derivatization. Activity tests were performed with crude lysates of overexpressing Escherichia coli cells and with purified enzyme. We established that zaxinone is a natural metabolite present in planta. Investigations of a corresponding rice mutant (zas) and activity bioassays performed by our group demonstrate that zaxinone a novel signaling molecule required for normal rice growth and development.