Newman I A
Physics Department, University of Tasmania, Hobart, Tasmania, Australia.
Plant Physiol. 1970 Aug;46(2):263-72. doi: 10.1104/pp.46.2.263.
Measurements have been made on the initial stages of the transport of carbon-14-labeled indoleacetic acid in the coleoptile of Avena sativa L. Concentrations of mobile and immobilized indoleacetic acid are related to both distance and time during the first 2 hours after application of the indoleacetic acid at several concentrations to the top of the decapitated coleoptile.At the lowest concentration of indoleacetic acid applied (0.3 mum), the graphs of concentration against distance are linear from near the top of the coleoptile to the front of the indoleacetic acid stream. The indoleacetic acid possesses a definite front moving at constant speed. In the region of the front the graphs are linear even with concentrations above 1 mum applied.A large proportion of the mobile indoleacetic acid in the coleoptile does not move with the speed of the front of the stream. The rate of immobilization of indoleacetic acid by a cell increases with time after the arrival of the indoleacetic acid. Each cell must pass on to the next nearly all the indoleacetic acid it initially receives.Effects of indoleacetic acid application for a short time are investigated, as is the effect of triiodobenzoic acid on indoleacetic acid transport. It is deduced that diffusion does not play a major part in the normal transport of auxin in the coleoptile.
已对燕麦胚芽鞘中碳 - 14标记的吲哚乙酸运输的初始阶段进行了测量。在将几种浓度的吲哚乙酸施加到去顶胚芽鞘顶部后的最初2小时内，可移动和固定化吲哚乙酸的浓度与距离和时间都有关系。在所施加的最低吲哚乙酸浓度（0.3 μM）下，浓度与距离的关系图从胚芽鞘顶部附近到吲哚乙酸流前端呈线性。吲哚乙酸具有以恒定速度移动的明确前沿。在前沿区域，即使施加浓度高于1 μM，关系图也是线性的。胚芽鞘中很大一部分可移动吲哚乙酸的移动速度与液流前沿的速度不同。吲哚乙酸到达细胞后，细胞对其固定的速率随时间增加。每个细胞必须将其最初接收的几乎所有吲哚乙酸传递给下一个细胞。研究了短时间施加吲哚乙酸的效果以及三碘苯甲酸对吲哚乙酸运输的影响。据推断，扩散在胚芽鞘中生长素的正常运输中不起主要作用。
