Quantification and mapping of growth patterns. The direction of root growth over time was quantified by taking measurements of the angle of a root segment in relation to a vertical line, with right being positive degrees and left as negative degrees. Values for each plant cultivar in ground control (A) and flight (B) in each image, spanning growth through 8.5 days, were averaged and then plotted with Microsoft Excel (see Methods for operational details). The two different cultivars represented on the imaging plate are WS (blue line) and Col-0 (green line). The y-axis shows the degree of deviation from the vertical the root presents at each 6 hour time point and the x-axis shows the corresponding dates the images were taken. Each cultivar plot line is an average taken from measurements of several roots: GC WS: 8 roots; GC Col-0: 3 roots; FLT WS: 7 roots; FLT Col-0: 4 roots. The error bars included with each time point reflect the Standard Error of the Mean.
Paul et al. BMC Plant Biology 2012 12:232 doi:10.1186/1471-2229-12-232