PURIFICATION OF MITOCHONDRIA AND MITOCHONDRIAL NUCLEIC-ACIDS FROM EMBRYOGENIC SUSPENSION-CULTURES OF A GYMNOSPERM, LARIX X LEPTOEUROPAEA

After a number of attempts to isolate mitochondria from different coni fer tissues, embryogenic suspension cultures of hybrid larch (Larix x leptoeuropaea) were developed which enabled the purification of mitoch ondria using slight modifications to standard techniques. The mitochon drial purity was verified by analysis of the mitochondrial RNA, DNA an d proteins. The larch mitochondrial genome size is surprisingly large (> 1000 kbp) and the polypeptide pattern differs greatly from those of wheat or potato mitochondria, suggesting that valuable evolutionary i nsights will be gained from comparisons between gymnosperm and angiosp erm mitochondria. The ease with which embryogenic conifer suspensions can be initiated and used for mitochondrial purification implies that they will be the material of choice for future studies of this type.