ULTRASTRUCTURAL-LOCALIZATION OF THE POLYSACCHARIDIC COMPONENT DURING THE SPORODERM ONTOGENY OF THE POLLEN GRAIN OF SCILLA-PERUVIANA (LILLIACEAE) AND CAPSICUM-ANNUUM (SOLANACEAE)

The ultrastructural localization of the polysaccharidic component of t he pollen wall and its formation during pollen ontogeny are analyzed u sing an easy cytochemical method that we have previously developed: ph osphotungstic acid (PTA) staining. The results reveal the different ch emical composition of the layers forming the sporoderm, and indicate t hat the polysaccharidic component is concentrated in endexine and inti ne. Moreover, this technique allows the visualization of both inner la yers from the beginning of their formation, when it is not possible to distinguish them on conventionally stained sections; in Scilla and Ca psicum, the endexine starts its deposition just after the release from the tetrad, and the intine at the late vacuolated stage. This cytoche mical method constitutes an interesting approach of studying the proce ss of formation of the different wall layers and their ultrastructure during pollen development. We propose the PTA as an easy and repetitiv e technique for analyzing the localization of the polysaccharidic comp onent during the ontogeny of the pollen wall.