Rayle D L, Evans M L, Hertel R
Proc Natl Acad Sci U S A. 1970 Jan;65(1):184-91. doi: 10.1073/pnas.65.1.184.
The early time course (0-30 min) of the action of auxin (3-indoleacetic acid) on the elongation of segments from corn coleptiles was studied, using a high-resolution continuous recording technique. Two different effects of auxin were observed: (1) After addition of low auxin concentrations (2 x 10(-7)M) to 4-mm sections, a very rapid (2-3 min) enhancement of elongation was found. Similar early responses were seen following the addition of low concentrations of the methyl ester of indoleacetic acid. (2) Following a large step-up in the auxin level (10(-5), 10(-4), or 10(-3)M), a rapid transient decrease was observed one to three minutes after the addition of indoleacetic acid. It lasted 10-15 minutes at which time the steady rate of auxin-promoted elongation became evident. Similar kinetic patterns of auxin effects other than on elongation and the implications of the findings on hypotheses of the primary action of auxin are discussed.
利用高分辨率连续记录技术，研究了生长素（3-吲哚乙酸）对玉米胚芽鞘切段伸长作用的早期时间进程（0 - 30分钟）。观察到生长素的两种不同效应：（1）向4毫米切段中添加低浓度生长素（2×10⁻⁷M）后，发现伸长迅速增强（2 - 3分钟）。添加低浓度吲哚乙酸甲酯后也观察到类似的早期反应。（2）生长素水平大幅升高（10⁻⁵、10⁻⁴或10⁻³M）后，添加吲哚乙酸一到三分钟后观察到快速的短暂下降。持续10 - 15分钟，此时生长素促进伸长的稳定速率变得明显。讨论了生长素除对伸长作用外的其他类似动力学模式以及这些发现对生长素主要作用假说的意义。
