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Plant Physiology 79:194-198 (1985) © 1985 American Society of Plant Biologists Ethylene and the Growth of Rice Seedlings 1MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
Etiolated whole rice seedlings enclosed in sealed vials produced ethylene at a rate of 0.9 picomole per hour per seedling. When 2-centimeter-long shoots were subdivided into 5-millimeter-long sections, the sections containing the tip of the shoot evolved 37% of the total ethylene with the remaining 63% being produced along a gradient decreasing to the base of the shoot. The tip of the coleoptile also had the highest level of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid and of the ethylene-forming enzyme activity. Ethylene is one of the factors controlling coleoptile elongation. Decapitation of the seedling reduced ethylene evolution to one-third its original level and inhibited coleoptile growth. In short-term experiments, the growth rate of decapitated seedlings was restored to almost that of intact seedlings by application of ethylene at a concentration of 10 microliters per liter. Apart from ethylene, O2 also participates in the control of coleoptile growth. When rice seedlings were grown in a gas mixture of N2 and O2, the length of the coleoptiles reached a maximum at a concentration of 2.5% O2. Lower and higher concentrations of O2 reduced coleoptile growth. The effect of exogenous ethylene on coleoptile growth was also O2 dependent.
1 Supported by the National Science Foundation through Grant No. PCM 81-09764 and by the United States Department of Energy under Contract No. DE-AC02-76ER 1338. This article has been cited by other articles:
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