Plasmodesmata linking the root cap and root in primary roots Zea mays are restricted to approx. 400 protodermal cells bordering approx. 110000 μm2 of the calyptrogen of the root cap. This area is less than 10% of the cross-sectional area of the root-tip at the cap junction. Therefore, gravitropic effectors moving from the root cap to the root can move symplastically only through a relatively small area in the centre of the root. Decapped roots are non-responsive to gravity. However, decapped roots whose caps are replaced immediately after decapping are strongly graviresponsive. Thus, gravicurvature occurs only when the root cap contacts the root, and symplastic continuity between the cap and root is not required for gravicurvature. Completely removing mucilage from the root tip renders the root non-responsive to gravity. Taken together, these data suggest that gravitropic effectors move apoplastically through mucilage from the cap to the root.
|Original language||English (US)|
|Number of pages||9|
|Journal||Annals of Botany|
|State||Published - Oct 1989|
Bibliographical noteFunding Information:
ACKNOWLEDGMENTS This research was supported by grants from the National Aeronautics and Space Administration (NASA) and the Research Incentive Program of Wright State University.
- Open meristem
- Root cap
- Root gravitropism
- Zea mays