ISSN:
1399-3054
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Young excised coleoptiles from dark grown wheat have their cell growth promoted by gibberellic acid (GA3), while sections from older coleoptiles have their cell growth promoted by auxin. The GA3 response has a much longer lag period than that of auxin. Neither GA3 nor auxin has any effect on 14C-leucine and 14C-uridine incorporation and uptake after 1 h, indicating that the lag in growth stimulation following GA3 application is not associated with changes in protein or RNA synthesis. Following a 6 h incubation there are small increases in 14C-leucine and 14C-uridine incorporation in response to both GA3 and auxin, and in the case of auxin this is associated with increased uptake. Studies on protein and RNA turnover using pulse-chase experiments have shown that both GA3 and auxin have no effect on protein and RNA stability. There are, however, developmental changes in RNA and protein synthesis that should be considered in any explanation of the mechanism of action of these hormones on cell growth. Young GA3-sensitive tissue has high rates of RNA synthesis and low protein and RNA turnover, while auxin-sensitive tissue has low rates of RNA synthesis, slightly higher rates of RNA turnover and much higher rates of protein turnover. The evidence overall favours more effective utilisation by GA3 and auxin of a basal control level of RNA and protein synthesis and turnover in coleoptile tissue.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1399-3054.1982.tb00311.x
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