Maize Mitochondria: Cytochromes of Fertile and Cytoplasmic Male-sterile Lines.

Cytochromes a + a(3), b, and c of mitochondria prepared from fertile and cytoplasmic male-sterile single- and double-cross maize (Zea mays L.) lines were examined by difference spectra at 25 C. The sterile lines contained the full complement of cytochromes, and absorption maxima were identical for each fertile-sterile combination. A small, but significant, increase of b cytochromes was detected in each sterile line, whereas the quantities of cytochromes a + a(3) and c were essentially unchanged. The yield of mitochondrial protein per gram of tissue was higher for the single-than for the double-cross, whereas the sterile cytoplasm did not affect ultimate mitochondrial yield.