Auxin transport is required for hypocotyl elongation in light-grown but not dark-grown Arabidopsis
Auxin transport is required for hypocotyl elongation in light-grown but not dark-grown Arabidopsis
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DOI：
10.1104/pp.116.2.455
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发表时间：
1998-02-01
期刊：
影响因子：
7.4
通讯作者：
Estelle, M
中科院分区：
文献类型：
--
作者：
Jensen, PJ;Hangarter, RP;Estelle, M
许多生长素反应依赖于吲哚乙酸的再分配和/或极性运输。生长素的极性运输可以通过施用植物生长素如1-萘基邻苯二甲酰胺酸（NPA）来抑制。当拟南芥幼苗在含有1.0 μ M NPA的培养基上生长时，下胚轴和根的伸长和向重力性受到强烈抑制。然而，当生长在黑暗中，NPA扰乱重力反应，但不影响伸长率。NPA对下胚轴伸长的抑制程度以能量密度依赖的方式增加，在白色光为50 μ mol·m（-2）·s（-1）时抑制最大，约为75%。在连续蓝光或远红光下生长的植物表现出与白光生长的植物相似的NPA诱导的下胚轴抑制。在连续红光下生长的植物表现出较少的NPA诱导的抑制。感光体突变体的分析表明光敏色素和隐花色素参与介导这种NPA反应。一些生长素抗性突变体的下胚轴在光照下对NPA的敏感性降低，但这些突变体的黄化苗的长度与野生型相似。这些结果表明，光NPA诱导的抑制在拟南芥中有显着的效果，并建议，生长素有更重要的作用，在光生长的伸长反应比在黑暗中生长的幼苗。
Many auxin responses are dependent on redistribution and/or polar transport of indoleacetic acid. Polar transport of auxin can be inhibited through the application of phytotropins such as 1-naphthylphthalamic acid (NPA). When Arabidopsis thaliana seedlings were grown in the light on medium containing 1.0 mu M NPA, hypocotyl and root elongation and gravitropism were strongly inhibited. When grown in darkness, however, NPA disrupted the gravity response but did not affect elongation. The extent of inhibition of hypocotyl elongation by NPA increased in a fluence-rate-dependent manner to a maximum of about 75% inhibition at 50 mu mol m(-2) s(-1) of white light. Plants grown under continuous blue or far-red light showed NPA-induced hypocotyl inhibition similar to that of white-light-grown plants. Plants grown under continuous red light showed less NPA-induced inhibition. Analysis of photoreceptor mutants indicates the involvement of phytochrome and cryptochrome in mediating this NPA response. Hypocotyls of some auxin-resistant mutants had decreased sensitivity to NPA in the light, but etiolated seedlings of these mutants were similar in length to the wild type. These results indicate that light has a significant effect on NPA-induced inhibition in Arabidopsis, and suggest that auxin has a more important role in elongation responses in light-grown than in dark-grown seedlings.