AMYLOPLASTS ARE NECESSARY FOR FULL GRAVITROPIC SENSITIVITY IN ROOTS OF ARABIDOPSIS-THALIANA
AMYLOPLASTS ARE NECESSARY FOR FULL GRAVITROPIC SENSITIVITY IN ROOTS OF ARABIDOPSIS-THALIANA
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DOI：
10.1007/bf00392808
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发表时间：
1989-02-01
期刊：
影响因子：
4.3
通讯作者：
SACK, FD
中科院分区：
文献类型：
--
作者：
KISS, JZ;HERTEL, R;SACK, FD
本研究以拟南芥（Arabidopsis thaliana（L.）Heynh是向重力的（T.卡斯帕和B.G. Pickard，1989，Planta 177，185-197）提出了关于淀粉和造淀粉体在重力感知中起作用的假设的问题。我们比较了这种无淀粉突变体和野生型（WT）向重力性的动力学。从几个参数来看，野生型根比TC 7根对重力的反应更灵敏：（1）垂直生长的TC 7根相对于重力矢量的方向不如WT根。(2)在重力刺激后弯曲的时间过程中，与WT根相比，TC 7根的弯曲延迟并减少。(3)TC 7根弯曲小于WT根后，一个单一的，短（诱导）期的重力刺激，和WT，但不是TC 7，根弯曲响应于1分钟的水平曝光。(4)野生型根弯曲比TC 7根响应于间歇性刺激（重复短时间的水平暴露）; WT根弯曲响应于10秒或更少的刺激，但TC 7根需要2分钟的刺激来产生弯曲。两种基因型的生长速率相等。我们的结论是WT根比TC 7根更敏感的重力。在TC 7根中，淀粉对于重力感知是不需要的，但是对于完全敏感性是必需的;因此，在野生型拟南芥根中，造粉体可能起平衡石的作用。此外，由于使用低重力的离心研究表明，无淀粉质体是相对致密的，是TC 7柱细胞中最可移动的组分，因此无淀粉质体也可能起平衡石的作用。
The observation that a starchless mutant (TC7) of Arabidopsis thaliana (L.) Heynh, is gravitropic (T. Caspar and B.G. Pickard, 1989, Planta 177, 185-197) raises questions about the hypothesis that starch and amyloplasts play a role in gravity perception. We compared the kinetics of gravitropism in this starchless mutant and the wild-type (WT). Wild-type roots are more responsive to gravity than TC7 roots as judges by several parameters: (1) Vertically grown TC7 roots were not as oriented with respect to the gravity vector as WT roots. (2) In the time course of curvature after gravistimulation, curvature in TC7 roots was delayed and reduced compared to WT roots. (3) TC7 roots curved less than WT roots following a single, short (induction) period of gravistimulation, and WT, but not TC7, roots curved in response to a 1-min period of horizontal exposure. (4) Wild-type roots curved much more than TC7 roots in response to intermittent stimulation (repeated short periods of horizontal exposure); WT roots curved in response to 10 s of stimulation or less, but TC7 roots required 2 min of stimulation to produce a curvature. The growth rates were equal for both genotypes. We conclude that WT roots are more sensitive to gravity than TC7 roots. Starch is not required for gravity perception in TC7 roots, but is necessary for full sensitivity; thus it is likely that amyloplasts function as statoliths in WT Arabidopsis roots. Furthermore, since centrifugation studies using low gravitational forces indicated that starchless plastids are relatively dense and are the most movable component in TC7 columella cells, the starchless plastids may also function as statoliths.