Dissertations and Theses @ UNI
Availability
Open Access Thesis
Keywords
Corn--Cytology; Proteins--Synthesis;
Abstract
Many features of plant development illustrate the plasticity of plant systems. Committment [sic] to one developmental state need not be permanent; many cells can exhibit totipotency in culture, and the normal course of differentiation can be altered at many points by environmental influences. Developmental controls in plant systems can be regarded as largely exogenous to the cell, and continuously maintained. One of the more difficult problems of developmental botany has been the switch from vegetative to reproductive growth of an apical meristem, and the control of morphogenesis of the inflorescence. Postlethwait and Nelson (1964) suggested that the development of the maize inflorescence encompasses a number of genetic switchpoints at which the normal genotype provides additional information necessary for the continued proper formation of the inflorescence. Such changes in genetic information might result in changes in the protein complement of affected cells. In this study, the soluble proteins of morphologic segments of the pistillate inflorescence of maize corresponding to developmental switchpoint segments as located by Postlethwait and Nelson (1964) were examined for differences between segments, possibly indicative of changes in gene expression. Segments of apex, branch primordia, and spikelet primordia sections of the apex were solubilized in 9 M urea, 4 % Nonidet P-40. Following centrifugation, supernatent was assayed for protein concentration. Eight micrograms of solubilized protein solution, 2 % in both 3.5-10 pH ampholines and 2-mercaptoethanol, was applied to first-dimension polyacrylamide tube gels; these were electrofocused at 800 V (constant voltage) for 18 hand equilibrated in SDS-containing buffer for 5 min. Buffer was drained and gels stored at -40°c prior to use. Second-dimension gels were linear gradient gels, 10-15 % polyacrylamide. First dimension gels were applied and molecular weight markers (81-17.5 kilodaltons (kD)) placed alongside; both were sealed in place with overlay agarose. Electrophoresis was done at 160 mA (constant current) for 10-12 h. Fixed gels were stained by the Gelcode silver-stain protocol, and 6 gels representative of each segment examined on a spot-by-spot basis. Spots present on 5/6 gels we r e numbered and recorded. Reproducibility was assessed in the first dimension by relative mobility of pI markers in the tube gels, and in the first and second dimensions by global and local pattern analysis (Daufeldt and Harrison 1984). Differences between segment maps were found. Twenty-nine polypeptide spots were found to be stage-associated, occurring in one or two of the three morphologic segment maps. The majority (23) of these resolved in the basic portion of the gel. Protein differences between segments of the inflorescence corresponding to apex, branch primordium, and spikelet primordia structures was demonstrated. Both quantitative and apparent qualitative changes were observed. It was concluded that these results support an interpretation of early female inflorescence development in maize as consisting, in part , of protein changes at two known switchpoints, and are consistent with the model proposed by Postlethwait and Nelson (1964). It remains to be demonstrated that the proteins in question are concerned specifically with the development of the structures they accompany.
Year of Submission
1987
Degree Name
Master of Arts
Department
Department of Biology
First Advisor
Alan R. Orr
Second Advisor
Robert Seager
Third Advisor
Virginia Berg
Date Original
1987
Object Description
1 PDF file (98 leaves)
Copyright
©1987 Catherine Thompson Howard
Language
en
File Format
application/pdf
Recommended Citation
Howard, Catherine Thompson, "Changes in the Protein Composition of the Female Inflorescence of Zea mays L. During Early Development" (1987). Dissertations and Theses @ UNI. 2985.
https://scholarworks.uni.edu/etd/2985
Comments
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