Data on isolation, purification and transfer of mitochondria from a cy
toplasmic male sterile line of the ''Ogura'' type of Raphanus sativus
to a male fertile line of Brassica napus are reported. Microinjection
has been used for the transfer of the donor mitochondria to the recipi
ent protoplasts. The injected protoplasts were identified and followed
individually throughout their development using a computerized micros
cope stage which greatly enhanced the number of injections (five-fold)
. The transferred donor mitochondria were stably maintained during sev
eral successive cell divisions, revealing that they were viable and fu
nctional. Several calluses were obtained from injected protoplasts wit
hout using any selection pressure. Restriction fragment length analysi
s of seventeen calluses, using mitochondrial DNA probes, indicated tha
t three contained the donor ''Ogura'' type mitochondria. No recombinan
t types of mitochondria have been observed. Flow cytometric and karyot
ype analyses of the calluses revealed the presence of similar amount o
f DNA and chromosome number as those of the recipient plants of B.napu
s. The application of microinjection for the manipulation of cytoplasm
ic composition is discussed.