Department of Biochemistry, Mahatma Phule Krishi Vidyapeeth, Rahuri 413 722, India
*Corresponding author. E-mail: shivajimunjal@Rediffmail.com
†Part of Ph. D. Thesis submitted by the senior author to the Post Graduate Institute, Mahatma Phule Krishi Vidyapeeth Rahuri.
Respiratory activities in vegetative tissues and the isolated mitochondria of etiolated seedlings and reproductive tissues were studied in two cytoplasmic male sterile (CMS) lines having the same A1 cytoplasm with different nuclear backgrounds of pearl millet along with their maintainer, restorer and restored lines. In addition, the assays of cytochrome c oxidase and succinate dehydrogenase were performed in isolated mitochondria. Cyanide–sensitive, cyanide–insensitive and total respirations in vegetative tissues and isolated mitochondria were lower in both the CMS lines than their respective maintainers, restorers and restored hybrids. Except in CMS lines, uptake of O2 during anther development increased from premeiotic to postmeiotic stage in all the lines. Consumption of O2, however, declined from meiotic to postmeiotic stage in the anthers of CMS lines. Pure mitochondrial preparations were obtained which were 92–94% intact. Enzymes, cytochrome c oxidase (complex IV) and succinate dehydrogenase (complex II) showed lower activities in both the CMS lines than their respective maintainer, restorer and restored hybrids. The CMS lines also displayed lower levels of nuclear encoded enzymes, viz., alternative oxidase and succinate dehydrogenase.
cytoplasmic male sterility, cytochrome c oxidase, succinate dehydrogenase, respiration, O2 uptake
