Research Institute, Canada Department of Agriculture, University Sub Post Office, London 72, Ontario, Canada.
Plant Physiol. 1972 Jun;49(6):957-60. doi: 10.1104/pp.49.6.957.
2,4-Dichlorophenoxyacetic acid had a multiple effect on the development of indoleacetic acid oxidase isoenzymes in tobacco callus tissues (Nicotiana tabacum, cv. White Gold) cultured in vitro, and the development of these isoenzymes was differentially associated with growth promotion or inhibition depending on the concentration of 2,4-dichlorophenoxyacetic acid. At low concentrations (0.1 to 1 mum) it promoted the development of a fast migrating isoenzyme A(5) accompanied by stimulation of a tumor-type growth. At high concentrations (10 to 100 mum), it inhibited the development of the fast migrating isoenzymes but promoted a sharp rise in others with slower electrophoretic mobilities, which was accompanied by growth inhibition. The implications are that 2,4-dichlorophenoxyacetic acid might alter the level of endogenous auxins through its dual effects on the oxidase isoenzyme system.
2,4-二氯苯氧乙酸对烟草愈伤组织（Nicotiana tabacum cv.White Gold）中吲哚乙酸氧化酶同工酶的发育有多种影响，这些同工酶的发育与生长促进或抑制的相关性因 2,4-二氯苯氧乙酸的浓度而异。在低浓度（0.1 至 1μm）下，它促进快速迁移同工酶 A（5）的发育，同时刺激肿瘤型生长。在高浓度（10 至 100μm）下，它抑制快速迁移同工酶的发育，但促进具有较慢电泳迁移率的其他同工酶的急剧上升，同时伴有生长抑制。这意味着 2,4-二氯苯氧乙酸可能通过对氧化酶同工酶系统的双重作用来改变内源性生长素的水平。
