CYTOSKELETAL ORGANIZATION AND POLLEN-TUBE GROWTH

The growth of pollen tubes is characterized by intense secretory activ ity in the tip region. This process of vesicle-mediated secretion and tip growth is strongly influenced by calcium gradients. The cytoskelet al apparatus is also critically involved, as it is required for the tr anslocation of organelles along the tube (a prerequisite for tube exte nsion) and for the transport of the generative/sperm cells, The microt ubules and actin filaments probably have distinct functions that relat e to different, but related, cytological events within the pollen tube s. Both systems, as well as cytoskeleton-based motor proteins, are nec essary for the proper development and growth of the pollen tubes. Diff erent approaches have allowed the roles of several cytoskeletal compon ents to be deciphered, and it is now possible to speculate how they mi ght interact.