Analysis of cytomixis in tobacco microsporocytes with confocal laser scanning microscopy.

Confocal laser scanning microscopy for the first time is used to examine the structure of the tobacco microsporocytes involved in the intercellular migration of nuclei (cytomixis). As is observed, the cytomictic channels are distributed over the surface of tobacco microsporocytes in a non-random manner and their number depends on the meiotic stage. Analysis of non-squash cells demonstrates the differences in cytological patterns of cytomixis in a normal meiosis of control tobacco plants (SR1 line) and the abnormal meiosis of polyploids. As a rule, two to three adjacent cells are involved in cytomixis during meiosis of control tobacco plants; after cytomixis, several micronuclei are formed in recipient cells; cytoplasts (enucleated cells) are rare; and polyads are undetectable. In the meiosis of polyploids, cytomixis is massive, with a larger number of cells (sometimes, over ten) involved in nuclear migration simultaneously; recipient cells on completion of cytomixis develop tens of micronuclei; cytoplasts and polyads are frequently detectable.