Abstract
Tracheary elements are distinguished by annular, reticular and pitted patterns of secondary cell walls (SWs). These SW patterns have been considered to be regulated by cortical microtubules and actin filaments.
Xylem vessels are classified into two types, proto-xylem vessels and meta-xylem vessels. Most of work on the relation between SW formation and cytoskeleton has been performed for proto-xylem vessels. However the meta-xylem vessels have pits in the massive SWs and may give us a hint to cytoskeletal regulation in terms of SW formation. Therefore we tried to investigate cytoskeletal changes during the meta-xylem vessel differentiation, using an Arabidopsis cell culture expressing transcription factor VND6. Our results clearly showed that cortical microtubules regulate the patterns of SW. In contrast, actin filaments did not coexist with SWs nor the cortical microtubules, showing no direct relation to regulation of pitted type of SWs.
