7.トウモロコシ幼葉鞘における重力刺激によるIAA輸送の量と方向の変化(口頭発表)

概要

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The plant hormone auxin (indole-3-acetic acid (IAA)) plays important roles in response to external factors such as light and gravity. We have reported using maize coleoptiles that IAA was biosynthesized mainly at 0-2 mm tip region and that the synthesized IAA was continuously transported to basal part. We also showed that IAA distribution rapidly changed at upper and lower side of the coleoptile at 0-10mm region within 20 minutes after gravi-stimulation, and IAA level at top region was temporary increased and then decreased. Here, we examined details about the changes of IAA level and movement after gravi-stimulation. The amount of IAA at 0-3 mm tip was increased from about 200 to 250pg/tip during 20 min after gravi-stimulation, and then gradually decreased to the initial level until 120 min. Before and after the stimulation, 0-3 mm tips were excised and placed on agar blocks in a horizontal direction, and diffusible IAA levels were determined. The amount of IAA diffusing from tip to agar was decreased by gravi-stimulation. Thus, increasing level of endogenous IAA in the tip after gravi-stimulation could be explained by the decrease in the rate of IAA transport. To know details for IAA movement after gravi-stimulation we are also investigating the effect of NPA and BFA treatment comparing between before and after gravi-stimulation.
植物化学調節学会の論文
2007-10-05