Auxin response, but not its polar transport, plays a role in hydrotropism of Arabidopsis roots
Auxin response, but not its polar transport, plays a role in hydrotropism of Arabidopsis roots
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DOI：
10.1093/jxb/erl274
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发表时间：
2007-01-01
影响因子：
6.9
通讯作者：
Miyazawa, Yutaka
中科院分区：
文献类型：
--
作者：
Kaneyasu, Tomoko;Kobayashi, Akie;Miyazawa, Yutaka
植物在自然界中是无根的，需要探测和响应许多环境信号来调节它们的生长和方向。事实上，植物感知大量的环境信号并通过适当的向性做出反应，而生长素在这些反应中起着重要作用被广泛接受。最近对拟南芥的分析强调了生长素极性运输和生长素对向地性的差异反应的重要性。即便如此，生长素在嗜水性中的作用仍不清楚。为了明确生长素是否参与了亲水反应，我们用生长素内流抑制剂（3-氯-4-羟基苯基乙酸）、外流抑制剂（1-萘酞酸和2,3,5-三碘苯甲酸）和响应抑制剂（对氯苯氧异丁乙酸）处理拟南芥幼苗，并研究了它们对亲水和向地性反应的影响。与先前的报告一致，所有测试的化学物质都抑制了向地性。相比之下，只有生长素反应的抑制剂（对氯苯氧异丁乙酸）减少了向水性，而生长素流入或流出的抑制剂没有作用。这些结果表明，生长素反应除了其极性运输外，还在植物的亲水反应中发挥着明确的作用，并将为生长素介导的向性调节提出新的概念。
Plants are sessile in nature, and need to detect and respond to many environmental cues in order to regulate their growth and orientation. Indeed, plants sense numerous environmental cues and respond via appropriate tropisms, and it is widely accepted that auxin plays an important role in these responses. Recent analyses using Arabidopsis have emphasized the importance of polar auxin transport and differential auxin responses to gravitropism. Even so, the involvement of auxin in hydrotropism remains unclear. To clarify whether or not auxin is involved in the hydrotropic response, Arabidopsis seedlings were treated with inhibitors of auxin influx (3-chloro-4-hydroxyphenylacetic acid), efflux (1-naphthylphthalemic acid and 2,3,5-triiodobenzoic acid), and response (p-chlorophenoxyisobutylacetic acid), and their effects were examined on both hydrotropic and gravitropic responses. In agreement with previous reports, gravitropism was inhibited by all the chemicals tested. By contrast, only an inhibitor of the auxin response (p-chlorophenoxyisobutylacetic acid) reduced hydrotropism, whereas inhibitors for influx or efflux of auxin had no effect. These results suggest that auxin response, apart from its polar transport, plays a definite role in hydrotropic response, and will evoke a new concept for the auxin-mediated regulation of tropisms.