Figure 5

(a) Typical example of time evolution of root growth experiment with intrusion (experimental) and without intrusion (control). Both experiment and control set-ups are performed simultaneously under partial saturation conditions. Results show a change in root morphology and a distinct vertical growth pattern in the presence of the intrusion. A magnified image of a portion of the root shows the deviation from the intrusion before briefly returning towards it. Treatment of water content (white) around the area shows minimal water near the secondary roots that have sprouted across the intrusion. (b) (top) Primary root growth curve for the images in (a). (middle) Total root growth curve (primary + secondary) for the images in (a). (bottom) Primary root length as function of root tip distance from suface. The solid line represents y = x, which corresponds to the case when the root grows in a straight vertical manner, perpendicular to the surface. In the presence of the intrusion, the root follows a vertical growth pattern. (c) (top) Bar graph showing the primary root length for experiments with intrusion compared to those without intrusion. A positive multiplicative factor shows that for a particular experimental run, the root length with intrusion is longer than without intrusion by the value of the factor (e.g. the primary root length in Run no° 1 is nearly twice longer than without intrusion). Conversely, a negative factor simply indicates the opposite, i.e. the root length without intrusion is longer than with intrusion (e.g. Run no° 3). (bottom) Bar graph showing the total root length for experiments with intrusion compared to those without intrusion.