Institute of Biological Sciences, University of Tsukuba, Sakura-mura.
Planta. 1979 Jan;145(4):323-9. doi: 10.1007/BF00388356.
Growth regulators were measured in extracts from the upper and lower halves of 7-mm apical segments of horizontally oriented, red-light-irradiated and non-irradiated roots of Zea mays L. cv. Golden Cross Bantam 70 which exhibit a georesponse only after an exposure to light. Abscisic acid (ABA) was measured by gas-liquid chromatography, auxin (indole-3-acetic acid, IAA) by the Avena straight-growth assay, and an unidentified growth inhibitor by a Zea root-growth assay. The ratio of ABA in the upper and lower halves was 1.6 in the irradiated roots and 1.0 in the non-irradiated ones. The total amount of ABA after irradiation was increased by a factor of ca. 1.8. The ratio of IAA in the upper and lower halves of irradiated and non-irradiated roots was 1:3.4 and 1:2.9, respectively. The content (or activity) of an unidentified growth inhibitor was highest in the lower halves of horizontally oriented roots which had been irradiated with red light. The unidentified growth inhibitor, rather than IAA or ABA, may be the major factor in the light-induced geotropic responsiveness in Zea roots.
在水平放置的、经红光照射和未照射的 Golden Cross Bantam 70 型玉米的 7mm 根尖段的上半部分和下半部分的提取物中测量了生长调节剂。只有在暴露于光下后，Golden Cross Bantam 70 型玉米的根尖才会表现出向地性反应。用气相色谱法测量脱落酸（ABA），用燕麦直生长测定法测量生长素（吲哚-3-乙酸，IAA），用玉米根生长测定法测量一种未鉴定的生长抑制剂。照射根的上半部分和下半部分的 ABA 比值为 1.6，未照射根的比值为 1.0。照射后 ABA 的总量增加了约 1.8 倍。照射和未照射根的上半部分和下半部分的 IAA 比值分别为 1:3.4 和 1:2.9。在经红光照射的水平放置的根的下半部分，未鉴定的生长抑制剂的含量（或活性）最高。未鉴定的生长抑制剂，而不是 IAA 或 ABA，可能是玉米根中光诱导向地性反应的主要因素。
