This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Shen-Miller, J. Articles by Wojciechowski, M. Search for Related Content PubMed PubMed Citation Articles by Shen-Miller, J. Articles by Wojciechowski, M. Agricola Articles by Shen-Miller, J. Articles by Wojciechowski, M.

Articles

Regions of Differential Cell Elongation and Mitosis, and Root Meristem Morphology in Different Tissues of Geotropically Stimulated Maize Root Apices ¹

Division of Biological and Medical Research, Argonne National Laboratory, Argonne, Illinois 60439

We examined cell length, mitosis, and root meristem "cuticle" in different tissues of geostimulated, red light-exposed primary roots of corn (Zea Mays, Wisconsin hybrid 64A x 22R). The examination was done at 15-minute intervals for a period of 240 minutes. Differences in cell elongation between the upper and lower sides were most prominent between 1.5 and 2.5 mm from the root meristem; the outer cortex had the greatest elongation growth, and the upper cells showed a significant increase in length compared to the lower. A differential mitosis was also found, with the lower tissue being greater. We infer that the mitotic activity is indicative of cell division, and this division occurs strictly in the first 1.5 mm of the root meristem. The combined effect of differential cell elongation and cell division results in the localization of the geotropic curvature in the 1.5- to 2.5-mm region from the root meristem. Mitosis that occurs primarily in the cortex and stele were asynchronous; the peak of cortical division preceded that of the stele. Both peaks occurred before the peak of geotropism. A densely stained layer separates the cap from the root meristem. This layer is thinner at the apex of the root meristem. The area of the thin region increased with time and peaked at 180 minutes after geostimulation, which was coincidental with the peak of the geotropic response.

This article has been cited by other articles:

				M. Sivaguru and W. J. Horst The Distal Part of the Transition Zone Is the Most Aluminum-Sensitive Apical Root Zone of Maize Plant Physiology, January 1, 1998; 116(1): 155 - 163. [Abstract] [Full Text]