Correlation of Mitochondrial Activities and Plant Vigor with Genotypic Backgrounds in Maize and Soybeans
- W. D. Hanson,
- D. E. Moreland and
- C. R. Shriner2
Characteristics of mitochondria isolated from genotypes differing in plant vigor were evaluated with divergent selections from a population of Zea mays (L.) and selections within a broad-base population of random homozygous lines in Giycine max (L.) Merr. These selections differed markedly in plant growth by the sixth leaf (or trifoliolate leaf) stage of growth. Cytoplasmic backgrounds were controlled so that variability under nuclear gene control was investigated primarily. Significant variability among mitochondria isolated from soybean genotypes was found for adenosine diphosphate-oxygen (ADP/O) ratios with malate. However, selection groups in both maize and soybean had similar ADP/O ratios. Mitochondria from vigorous selections had higher respiratory control ratios (RC) with malate and lower succinate to malate ratios (S/M) for ADP-activated (state-3) respiration than the nonvigorous selections in both maize and soybean material. No mitochondrial complementation between diverse soybean genotypes was found when realate, succinate, and nicotinamide adenine dinucleotide (NADH) were used as substrates. With α-ketoglutarate as substrate, no complementation for efficiency of phosphorylation was found between two pairs of soybean lines representing the extreme contrasts available. A highly significant reduction in state-3 oxidation rates occurred when the mitochondria were mixed; however, no differences in mitochondrial activities were found between vigorous and nonvigorous genotypes, a difference required if the complementation effect reflected a genotypic potential. Mitochondrial complementation effects did not appear to reflect productivity in soybeans.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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