Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam, Germany.
Institute of Geodesy and Photogrammetry, ETH-Hönggerberg, CH-8093 Zürich, Switzerland.
New Phytol. 2012 Jul;195(2):346-355. doi: 10.1111/j.1469-8137.2012.04162.x. Epub 2012 May 14.
• All living organisms on Earth are continually exposed to diurnal variations in the gravitational tidal force due to the Sun and Moon. • Elongation of primary roots of Arabidopsis thaliana seedlings maintained at a constant temperature was monitored for periods of up to 14 d using high temporal- and spatial-resolution video imaging. The time-course of the half-hourly elongation rates exhibited an oscillation which was maintained when the roots were placed in the free-running condition of continuous illumination. • Correlation between the root growth kinetics collected from seedlings initially raised under several light protocols but whose roots were subsequently in the free-running condition and the lunisolar tidal profiles enabled us to identify that the latter is the probable exogenous determinant of the rhythmic variation in root elongation rate. Similar observations and correlations using roots of Arabidopsis starch mutants suggest a central function of starch metabolism in the response to the lunisolar tide. The periodicity of the lunisolar tidal signal and the concomitant adjustments in root growth rate indicate that an exogenous timer exists for the modulation of root growth and development. • We propose that, in addition to the sensitivity to Earthly 1G gravity, which is inherent to all animals and plants, there is another type of responsiveness which is attuned to the natural diurnal variations of the lunisolar tidal force.
• 地球上所有的生物都持续受到太阳和月亮引起的昼夜变化的重力潮汐力的影响。 • 使用高时间和空间分辨率的视频成像，监测拟南芥幼苗的主根在恒定温度下长达 14 天的伸长情况。当将根置于连续光照的自由运行条件下时，每半小时伸长率的时程表现出一种振荡，这种振荡得以维持。 • 最初在几种光照方案下培养的幼苗的根随后处于自由运行条件下时，从幼苗中收集的根生长动力学与日月潮汐曲线之间的相关性使我们能够识别出后者可能是根伸长率节律变化的外源性决定因素。使用拟南芥淀粉突变体的根进行的类似观察和相关性表明，淀粉代谢在对日月潮汐的反应中起着核心作用。日月潮汐信号的周期性和伴随的根生长速率的调整表明，存在一个外源性定时器来调节根的生长和发育。 • 我们提出，除了所有动植物固有的对地球 1G 重力的敏感性之外，还有另一种类型的反应性，它与日月潮汐力的自然昼夜变化相协调。
