A computer-based video digitizer system is described which allows automated tracking of markers placed on a plant surface. The system uses customized software to calculate relative growth rates at selected positions along the plant surface and to determine rates of gravitropic curvature based on the changing pattern of distribution of the surface markers. The system was used to study the time course of gravitropic curvature and changes in relative growth rate along the upper and lower surface of horizontally-oriented roots of maize (Zea mays L.). The growing region of the root was found to extend from about 1 mm behind the tip to approximately 6 mm behind the tip. In vertically-oriented roots the relative growth rate was maximal at about 2.5 mm behind the tip and declined smoothly on either side of the maximum. Curvature was initiated approximately 30 min after horizontal orientation with maximal (50°) curvature being attained in 3 h. Analysis of surface extension patterns during the response indicated that curvature results from a reduction in growth rate along both the upper and lower surfaces with stronger reduction along the lower surface.

中文翻译：

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使用基于计算机的视频数字化仪分析玉米根部向地曲率期间的生长模式

描述了一种基于计算机的视频数字化仪系统，该系统允许对放置在植物表面上的标记进行自动跟踪。该系统使用定制软件计算沿植物表面选定位置的相对生长率，并根据表面标记分布的变化模式确定向地曲率的速率。该系统用于研究沿水平取向的玉米（Zea mays L.）根部上、下表面向地曲率的时间过程和相对生长速率的变化。发现根部的生长区域从尖端后面约 1 毫米延伸到尖端后面约 6 毫米。在垂直方向的根中，相对生长率在尖端后约 2.5 毫米处达到最大，并在最大值的两侧平稳下降。在水平定向后大约 30 分钟开始曲率，最大 (50°) 曲率在 3 小时内达到。响应过程中表面扩展模式的分析表明，曲率是由于沿上表面和下表面的生长速率下降而沿下表面的下降幅度更大。