CONFOCAL LASER-SCANNING MICROSCOPY OF MITOCHONDRIA WITHIN MICROSPORE TETRADS OF PLANTS USING RHODAMINE-123 AS A FLUORESCENT VITAL STAIN

The present study demonstrates that rhodamine 123 penetrates the callo se walls surrounding plant microspores before they are released from t etrads. The stain accumulates in active mitochondria due to the electr ical potential across the mitochondrial membrane, Accumulation of dye does not occur in mitochondria of fixed cells and fades quickly when m itochondrial activity is inhibited by exposure to carbonyl cyanide m-c hlorophenyl hydrazone. Rhodamine can be used as a viability test for m icrospores still within tetrads, thus making it possible to determine when during development genes leading to pollen sterility are expresse d. Rhodamine 123 is excited by blue (550 nm) light and can thus be use d with confocal laser scanning microscopy. Anthers of Nicotiana tabacu m, Oenothera villaricae, Silene dioica and Lycopersicum esculentum wer e studied here.