Degree Type


Date of Award


Degree Name

Doctor of Philosophy




The regulation of photosynthetic gene function was investigated in soybean and in the cyanobacterium Anacystis nidulans. Restriction endonuclease fragment analysis was used to elucidate the mode of transmission of chloroplast DNA in Glycine max and G. soja. Maternal inheritance was demonstrated for progeny of reciprocal crosses of three G. max and one G. soja genotypes. Two related projects were undertaken to examine genetic and physiological effects of several loci conditioning chlorophyll retention or degradation. The mode of inheritance of 153 green-cotyledon genotypes was characterized. Chloroplast DNA from 15 cytoplasmically inherited genotypes was analyzed by using restriction endonucleases, to assess heterogeneity among the genotypes. With the enzymes employed, no differences were detected in the fragment patterns of the 15 genotypes. In the third project, the genetic interaction of five loci was investigated in relation to chlorophyll retention in leaves, mature cotyledons, and seed coats. To this end, several isolines containing various combinations of recessive and dominant alleles were constructed. Chlorophyll content was measured at five developmental stages. The results suggested that either both proteins containing chlorophyll a and chlorophyll b were stabilized in green seeds, or only proteins containing chlorophyll b;Cells of A. nidulans were grown in the presence of sublethal doses of herbicides to assess changes occurring in the thylakoid membrane during adaptation. Total polar lipids and phycocyanin content increased in herbicide-adapted cells relative to control cells. Chlorophyll fluorescence indicated that the additional phycocyanin was incorporated into existing phycobilisomes.



Digital Repository @ Iowa State University,

Copyright Owner

Peggy M. Hatfield



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File Size

112 pages

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Genetics Commons