Basipetal auxin transport is required for gravitropism in roots of arabidopsis
Basipetal auxin transport is required for gravitropism in roots of arabidopsis
复制标题
DOI：
10.1104/pp.122.2.481
复制
发表时间：
2000-02-01
期刊：
影响因子：
7.4
通讯作者：
Muday, GK
中科院分区：
文献类型：
--
作者：
Rashotte, AM;Brady, SR;Muday, GK
据报道，生长素运输发生在两个不同的极性，顶和基，在两个不同的根组织。本研究的目的是确定是否两个极性的吲哚-3-乙酸（IAA）运输发生在拟南芥根，并确定哪一个极性控制重力反应。生长素转运抑制剂NPA（naphthylphthalamic acid）在全球范围内对根的应用阻断了重力反应、根波动和根伸长。应用NPA后，立即根重力反应完全阻断，如通过自动视频数字化仪测量的。NPA抑制了拟南芥根中[H-3]IAA向基部的运输，而[C-14]苯甲酸的运输则不受影响。通过局部应用NPA抑制向基的IAA运输阻断重力反应。抑制向顶生长素运输的应用NPA在根冠交界处只有部分降低了在高NPA浓度的重力响应。切下的根尖，不接受生长素从地上部，表现出正常的重力反应。拟南芥突变体eir 1，它具有agravitropic根，表现出减少向基IAA运输，但野生型水平的向顶IAA运输。这些结果支持基瓣运输IAA控制拟南芥根向地性的假说。
Auxin transport has been reported to occur in two distinct polarities, acropetally and basipetally, in two different root tissues. The goals of this study were to determine whether both polarities of indole-3-acetic acid (IAA) transport occur in roots of Arabidopsis and to determine which polarity controls the gravity response. Global application of the auxin transport inhibitor naphthylphthalamic acid (NPA) to roots blocked the gravity response, root waving, and root elongation. Immediately after the application of NPA, the root gravity response was completely blocked, as measured by an automated video digitizer. Basipetal [H-3]IAA transport in Arabidopsis roots was inhibited by NPA, whereas the movement of [C-14]benzoic acid was not affected. Inhibition of basipetal IAA transport by local application of NPA blocked the gravity response. Inhibition of acropetal IAA transport by application of NPA at the root-shoot junction only partially reduced the gravity response at high NPA concentrations. Excised root tips, which do not receive auxin from the shoot, exhibited a normal response to gravity. The Arabidopsis mutant eir1, which has agravitropic roots, exhibited reduced basipetal IAA transport but wild-type levels of acropetal IAA transport. These results support the hypothesis that basipetally transported IAA controls root gravitropism in Arabidopsis.