Mitotic Cycle Regulation in the Meristem of Cultured Roots: The Principal Control Point Hypothesis
This paper was deliberately limited to the concept of and experimental evidence for two principal control points in the mitotic cycle of root meristem cells. The root meristem has been the vehicle for much research in cell population kinetics. The work of Laughlin9,10, with Allium in 1919 and Brown1 with Pisum in 1951 on temperature effects on the mitotic cycle attest to an early recognition of its advantages for such studies. Even today few experiments match the precision, breadth, and insight of Gray and Scholes2 in their growth and cellular analysis of Vicia faba roots. The work of Gray and Scholes and that of Lea11 undoubtedly contributed to the formulation of the universally accepted Howard and Pelc4 model of the mitotic cycle. The model coupled with the tools of radioisotope and high resolution auto-radiography, also developed with Vicia 14, and the theory of Quast1er12 and Quastler and Sherman13 formed the foundation of what is currently known as cell population kinetics. Wimber26 was one of the first to use these tools to describe the mitotic cycle of Tradescantia root tip cells and since the first experiments, much information has been gathered about the cell division cycle in plants.
KeywordsRoot Meristem Mitotic Cycle Helianthus Annuus Root Meristem Cell Mitotic Delay
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