Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802.
Plant Physiol. 1971 Nov;48(5):603-6. doi: 10.1104/pp.48.5.603.
Avena coleoptiles did not elongate when incubated with tryptophan under sterile conditions. Indole, anthranilic acid, and tryptamine promoted elongation. Under the same conditions, the tissue converted tryptophan-(14)C to IAA-(14)C. More IAA-(14)C was produced from indole-(14)C than from tryptophan-(14)C; however, the free tryptophan content of the tissue was also greatly increased by the indole treatment. Tryptophan-(14)C was readily taken up by the tissue but was mainly incorporated into protein and did not increase the free tryptophan level. When bean shoots were labeled with tryptophan-(14)C or indole-(14)C, the label incorporation into IAA-(14)C was very nearly the same. In this tissue the free tryptophan level in the tryptophan-(14)C and indole-(14)C treatments was also about equal. These results suggest that failure of exogenously supplied tryptophan to promote the elongation of Avena coleoptiles is a result of its predominant incorporation into protein and consequent unavailability for conversion to IAA.
在无菌条件下，用色氨酸孵育野燕麦胚芽鞘时，它们不会伸长。吲哚、邻氨基苯甲酸和色胺促进伸长。在相同条件下，组织将色氨酸-(14)C 转化为 IAA-(14)C。从吲哚-(14)C 中产生的 IAA-(14)C 比从色氨酸-(14)C 中产生的多；然而，吲哚处理也大大增加了组织中的游离色氨酸含量。色氨酸-(14)C 很容易被组织吸收，但主要被掺入蛋白质中，不会增加游离色氨酸水平。当豆芽用色氨酸-(14)C 或吲哚-(14)C 标记时，标记掺入 IAA-(14)C 的量几乎相同。在这种组织中，色氨酸-(14)C 和吲哚-(14)C 处理中的游离色氨酸水平也大致相等。这些结果表明，外源供应的色氨酸未能促进野燕麦胚芽鞘的伸长，是由于其主要掺入蛋白质中，因此无法转化为 IAA。
