Ishikawa H, Evans M L
Department of Plant Biology, Ohio State University, Columbus 43210.
Plant Physiol. 1990;94(3):913-8. doi: 10.1104/pp.94.3.913.
We examined the kinetics of electrotropic curvature in solutions of low electrolyte concentration using primary roots of maize (Zea mays L., variety Merit). When submerged in oxygenated solution across which an electric field was applied, the roots curved rapidly and strongly toward the positive electrode (anode). The strength of the electrotropic response increased and the latent period decreased with increasing field strength. At a field strength of 7.5 volts per centimeter the latent period was 6.6 minutes and curvature reached 60 degrees in about 1 hour. For electric fields greater than 10 volts per centimeter the latent period was less than 1 minute. There was no response to electric fields less than 2.8 volts per centimeter. Both electrotropism and growth were inhibited when indoleacetic acid (10 micromolar) was included in the medium. The auxin transport inhibitor pyrenoylbenzoic acid strongly inhibited electrotropism without inhibiting growth. Electrotropism was enhanced by treatments that interfere with gravitropism, e.g. decapping the roots or pretreating them with ethyleneglycol-bis-[beta-ethylether]-N,N,N',N' -tetraacetic acid. Similarly, roots of agravitropic pea (Pisum sativum, variety Ageotropum) seedlings were more responsive to electrotropic stimulation than roots of normal (variety Alaska) seedlings. The data indicate that the early steps of gravitropism and electrotropism occur by independent mechanisms. However, the motor mechanisms of the two responses may have features in common since auxin and auxin transport inhibitors reduced both gravitropism and electrotropism.
我们使用玉米（Zea mays L.，品种为Merit）的初生根，研究了低电解质浓度溶液中向电弯曲的动力学。当将根浸没在施加了电场的充氧溶液中时，根会迅速且强烈地向正极（阳极）弯曲。随着场强增加，向电反应的强度增加，潜伏期缩短。在场强为每厘米7.5伏时，潜伏期为6.6分钟，约1小时内弯曲达到60度。对于大于每厘米10伏的电场，潜伏期小于1分钟。对于小于每厘米2.8伏的电场没有反应。当培养基中加入吲哚乙酸（10微摩尔）时，向电性和生长均受到抑制。生长素运输抑制剂芘酰苯甲酸强烈抑制向电性，但不抑制生长。干扰向地性的处理（例如去掉根冠或用乙二醇 - 双 - [β - 乙氧基] - N，N，N'，N' - 四乙酸预处理）会增强向电性。同样，无向地性豌豆（Pisum sativum，品种为Ageotropum）幼苗的根比正常（品种为Alaska）幼苗的根对向电刺激更敏感。数据表明，向地性和向电性的早期步骤通过独立机制发生。然而，这两种反应的运动机制可能有共同特征，因为生长素和生长素运输抑制剂会同时降低向地性和向电性。
