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|Title:||Response of the maize genome to external and cellular environments|
|Author(s):||McMurphy, Lisa Marie|
|Doctoral Committee Chair(s):||Rayburn, A.L.|
|Department / Program:||Agriculture, Agronomy
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||The objective of this thesis was to investigate the effects of different types of environments on the structure and functioning of the maize genome. The external environment was altered by treatment of maize kernels with the fungicide captan and by adding coal fly ash and fly ash leachate to the soil. The cellular environment was investigated by observing differences in the structure and function of genomes of hybrids as compared to inbred lines.
Captan is the major seed treatment fungicide used to treat maize in the United States. It has great economic benefits in reduced tillage systems. Captan is reported to inhibit DNA synthesis in several animal systems. Maize kernels were treated with the recommended agronomic rate of captan. The resulting seedlings were analyzed by flow cytometry. The results of this study indicate that captan causes a reduction of maize nuclear DNA amount. The magnitude of the DNA loss is dependent upon the fertility of the growing media used.
Land application of coal fly ash is currently under consideration as a means of reducing the amount of industrial waste that must be landfilled. Maize seedlings were grown in soil contaminated with coal fly ash, weathered coal fly ash, and fly ash leachate. The seedlings were analyzed by flow cytometry. A multigenerational study was also performed. These studies indicate that while the weathered form of fly ash may be relatively inert, unweathered fly ash and fly ash leachate pose a significant threat to the environment by inducing nuclear alterations in plants.
When two diverse inbred lines are crossed to form a hybrid, some shuffling of the nuclear material may be required to insure proper functioning of the hybrid genome. Maize hybrids were analyzed by flow cytometry to determine the mode of DNA content inheritance in hybrids, and by AgNOR staining to determine relative nucleolar activity in the hybrids. These studies indicate an instability of DNA amount in certain F1 hybrids, and competition between the nucleolus organizer regions (NOR's) from the two parental genomes.
|Rights Information:||Copyright 1995 McMurphy, Lisa Marie|
|Date Available in IDEALS:||2011-05-07|
|Identifier in Online Catalog:||AAI9522150|