Importance of the cap cells in maize root gravireaction.

The length of the maize root cap differs significantly from one root to another. The gravireaction of roots appears to depend upon the cap length; when it is smallest, the downward curvature is lowest. Using a freezing technique, it was possible to destroy a part of the root cap and to observe that the smaller the number of root cap cells which remained, the less pronounced was the gravitropic response.