Root cell elongation

The hormonal regulation of root elongation in the intact plant is poorly understood. This is partly because all the major plant hormones can inhibit root cell elongation at physiological concentrations. Since roots produce or at least contain each of these inhibitors , it seems clear that root elongation must... 

The kinetics of inhibition of coleoptile cell elongation by supraoptimal concentrations of auxin also differ from the kinetics of inhibition of root cell elongation. In coleoptiles the initial effect of supraoptimal auxin is to promote cell elongation. This is followed by inhibition. In roots the initial effect of high concentrations of auxin is to inhibit elongation (McBride and Evans 1977). 

Caspar et al. (1972) suggested that the inhibition of root elongation by lAA may be caused by a metabolite of lAA, most probably 3-methyleneoxindole (3-MO). However, it has since been shown that purified 3-MO does not inhibit root elongation (Evans 1976c). These data in conjunction with the rapidity (15-20 min) with which intact root growth is inhibited by low concentrations of lAA, indicate that auxin inhibition of root cell elongation is a direct effect. 

Two processes are involved in plant growth, namely, cell division and cell elongation. The former process takes place only in specialized tissue, the meristematic regions, characteristically found at root and stem tips and in the buds that form leaves and flowers. Grasses, on the other hand, have a meristematic region between the leaves and the roots. During... 

As a hormone IAA has a broad range of effects on plants, altering tissue differentiation, root growth, cell elongation, and cell division.2413 The fastest observed response is an effect on cell elongation, which can be observed within 15-20 minutes.242 In A. thaliana IAA... 

Inhibits cell elongation. Also influences developmental cycle, leading to increased flowering and harvest. May also increase chlorophyll formation and root development Animals. 97% is eliminated within 24 hr, principally unchanged Plants. Converted to choline chloride Soil. Rapidly degraded by microbial activity. DTJ0 in 4 soils averaged 32 days at 10°C 1-28 days at 22°C. Low to medium mobility... 

Auxin-like responses, exudates, and initiation of adventitious roots affected. Cell elongation and division promoted or inhibited. Geotropic response lost. 

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