Cellular organisation and differentiation of organelles in pre-meiotic rice anthers.

ABSTRACT

Pre-meiotic cellular organisation of rice anthers has a great significance in pollen formation. We have used a combination of confocal laser and transmission electron microscopy (TEM) to characterise and differentiate organelles in pre-meiotic rice anthers. Along with the characteristic organelles in the cytoplasm the epidermal cells of the pre-meiotic rice anther are coated on their outer surface by a conspicuous bi-lamellate cuticle. Chloroplasts of the endothecium contain immature grana, thylakoids and also starch granules. These plastids clearly contain photosynthetic pigments as shown by autofluorescence in confocal microscope studies. Both confocal and TEM studies reveal clusters of mitochondria in the middle layer. The tapetum contains electron opaque ribosomes, bundles of mitochondria and plastids. The nuclei of the tapetum occupy a large volume of the cytoplasm indicating the onset of mitotic prophase. Intense Rhodamine 123 staining reveals that a major portion of the structurally indistinguishable organelles that were seen throughout the densely ribosomic cytoplasm of sporogenous cells are mitochondria.