Tubular and filamentous structures in pollen tubes: Possible involvement as guide elements in protoplasmic streaming and vectorial migration of secretory vesicles |
| |
Authors: | Werner W. Franke Werner Herth William J. VanDerWoude D. J. Morré |
| |
Affiliation: | (1) Department of Cell Biology, Institute of Biology II, University of Freiburg i. Br., Germany;(2) Department of Botany and Plant Pathology, Purdue University, Lafayette, Indiana, USA |
| |
Abstract: | Summary An ultrastructural study of the pollen tubes of Lilium and Clivia has demonstrated three different classes of longitudinal structures which could influence patterns of protoplasmic streaming and/or serve as guide elements in the vectorial migration of secretory vesicles: (a), cortical and noncortical microtubules; (b), microfilaments; and (c), subcortical tubules and cisternae of the endoplasmic reticulum (subsurface cisternae). Morphological details of these structures are described. Colchicine concentrations which lead to the complete disappearance of the microtubules affect neither germination of the pollen nor cytoplasmic streaming and tip growth of the elongating pollen tubes. Tip growth is initially uninhibited by cycloheximide, and cytoplasmic streaming is insensitive to this inhibitor. However, both of these processes are sensitive to cytochalasin B and vinblastine. Our results suggest that neither microtubules nor subsurface cisternae are essential for cytoplasmic streaming and directional secretion of cell surface materials in the pollen tube but would be consistent with an involvement of microfilamentous structures in these processes. Additionally, the possible importance of the lateral cross-link elements interconnecting all three types of structures is discussed. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|