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Characterization of temperature-sensitive chlorophyll-deficient mutants of sweet clover (Melilotus alba)
Abstract
A collection of chlorophyll-deficient mutants of sweetclover were grown at 17$\sp\circ$C or 26$\sp\circ$C to examine the temperature effect on the nature of their biochemical deficiency. In the first chapter, the literature pertaining to the function and biosynthesis of chlorophyll $a$ and $b$ and the light-harvesting chlorophyll-protein complexes and the characteristics of chlorophyll-deficient mutants, light- and temperature-sensitive mutants are briefly reviewed. The characteristics of chlorophyll $b$- deficient and virescent mutants are compared. In the second chapter, the systematic study of a collection of eight non-allelic chlorophyll-deficient mutants of sweetclover substantiate Oliver Nelson's 1967 proposal that a majority of chlorophyll-deficient mutants are not impaired in the biosynthesis of chlorophyll. Also, the data indicate that temperature-sensitivity is a general phenomenon of chlorophyll-deficient mutants. The ch10 and ch11 mutants of sweetclover may be good tools for studying the biosynthesis of chlorophyll $b$ and the LHC-II apoproteins and their assembly in the thylakoid membrane of higher plants. In the third chapter, the temperature-sensitive chlorophyll-deficient ch4 mutant of sweetclover was further investigated. It was shown that this mutant does indeed possess a reduced capacity to produce chlorophyll and also has a diminished accumulation of LHC-II apoproteins. An enzyme involved in the conversion of coproporphyrinogen III to protoporphyrinogen IX is likely a candidate for the defect in this mutant. The final chapter presents conclusions and predicts the future utilization of the unique characteristics of temperature-sensitive, chlorophyll-deficient mutants to solve the problems pertaining to chloroplast biochemistry and development.
Subject Area
Botany
Recommended Citation
Yang, Chi-Ming, "Characterization of temperature-sensitive chlorophyll-deficient mutants of sweet clover (Melilotus alba)" (1990). ETD collection for University of Nebraska-Lincoln. AAI9030160.
https://digitalcommons.unl.edu/dissertations/AAI9030160