AN ULTRASTRUCTURAL STUDY ON DIMORPHISM OF TAPETUM IN REHMANNIA GLUTINOSA

There were two different kinds of tapetal cells in Rehmannia glutinosa(Gaertn.)Libosch.The p-tapetum with small cells was derived from parietal layer and the c-tapetum with large cells was originated from connective tissue.Pro-Ubisch bodies were produced and excreted out of plasmolemma of p-tapetal and some c-tapetal cells.Ubisch bodies exist on the inner surface of p-tapetal cells,but no or very few Ubisch bodies can be observed on the locule surface of these c-tapetal cells,other kind of ctapetal cells did not produce pro-Ubisch bodies and Ubisch bodies,another kind of ctapetal cells degenerated before producing pro-Ubisch bodies,P-tapetum degenerated at the original place after mitosis of microspores.Degenerative signs began to appear in ctapetal cells in different pollen sac during meiosis,tetrads or microspore stage.Most ctapetal cells degenerated earlier than p-tapetum.After loss of the radial wall and the wall facing the locule,plasmolemma of c-tapetum was broken,and the degenerating cytoplasm and organelles moved into the anther locule.