Biochemical and cytological studies of mitochondrial development in chloramphenicol-induced rice coleoptiles.

The ultrastructure and respiratory activity of mitochondria in rice coleoptile grown in the presence and in the absence of an inibitor of mitochondrial protein synthesis (chloramphenicol) have been studied. It is shown that during the first 48 h of germination a rapid development of mitochondrial cristae takes place without notable influence of chloramphenicol on biogenesis of mitochondria. But the presence of the inhibitor has a significant effect in the subsequent period (48-144 h): a gradual and almost complete reduction of mitochondrial cristae is observed. These unusual "noncristate" mitochondria, although greatly lacking cytochrome oxidase, have a high respiratory activity. The respiration of "noncristate" mitochondria is resistant to KCN. It is supposed that chloramphenicol-induced rice coleoptile can be used as a new convenient object for studies of the nature of alternative oxidase as well as the biogenesis of mitochondria with cyanide-insensitive respiration.