TITLE	Peroxidase activity in relation to ethylene-induced rice (Oryza sativa L.) coleoptile elongation
AUTHOR	Tse-Min Lee Institute of Marine Biology, National Sun Yat-Sen University, Kaohsiung, Taiwan, Republic of China Yaw-Huei Lin Institute of Botany, Academia Sinica, Taipei, Taiwan, Republic of China
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ABSTRACT	Changes in the activities of soluble and cell wall-bound peroxidase (EC 1.11.1.7, donor: hydrogen-peroxide oxidoreductase) in relation to the regulation of coleoptile elongation were determined using rice (Oryza sativa L. cv. Taichung Native 1) seedlings grown in air or in air containing ethylene. Guaiacol and syringaldazine were used separately as the H donors for peroxidase assays. In air, both guaiacol and syringaldazine cell wall-bound peroxidase activity declined during coleoptile elongation but increased again to the initial level when elongation ceased. Soluble syringaldazine peroxidase activity in air-grown coleoptiles also showed an initial decline followed by a subsequent rise, but soluble guaiacol peroxidase activity remained essentially constant. Ethylene (10 µL/L) enhanced coleoptile elongation but decreased both guaiacol and syringaldazine peroxidase activities, especially the wall-bound forms. 2,5-Norbornadiene (NBD) at 3000 µL/L, an inhibitor of ethylene action, blocked both the ethylene-mediated coleoptile elongation and the decline of peroxidase activity. Ethylene at 50 µL/L reversed the effect of NBD. These results suggest that the activity of peroxidase, especially the cell wall-bound form, is inversely related to the elongation of rice coleoptiles.
KEYWORD	Oryza sativa L.; Coleoptile elongation; Ethylene; Peroxidase; 2,5-Norbornadiene;
ARTICLE INFO	Botanical Bulletin of Academia Sinica, Volume 37 Number 4 October 1996, page 239-245, 7 pages
PUBLISHER	Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China