01442nab a2200253 a 4500 AR-ReUNN 20260702003308.0 260630s2006 ag |||||||||||||||||eng eng Majumdar, S. K. 154505 Lowry, R. J. 154506 An electron microscope study of the barrier between vegetative and generative nuclei in the pollen of Gasteria armstrongii / S. K. Majumdar; R. J. Lowry 2006 5 páginas fot. byn. Ultrastructure studies of the pollen grains of Gasteria armstrongii revealed the existence of a barrier between the vegetative and generative nuclei. The layer is continuous with the intine of the pollen wall. It is suggested that the cisternae of the endoplasmic reticulum appear between the two nuclei and deposition of pectic substances occurs in them. Later the pectine containing cisternae line up in the equatorial region and fuse to from the layer. Finally the layer separates from the intine and becomes the envelope around the generative nucleus. The chemical nature of the barrier is discussed. Gasteria 154507 Liliaceae 115697 Polen 6254 Phyton : Revista Internacional de Botánica Experimental = International Journal of Experimental Botany 0031-9457 v. 28 n. 2 (1971) 238927 ART (IBONE)34595 239009 239009 239009 AR-ReUNN spa AR-ReUNN aacr2