Figure 3.

Metal ball dispenser. (A) Photograph of the home-made 96-well metal ball dispenser without metal balls. (B) The same device with 96 metal balls loaded on top of it. The ball-loading device was created by placing several sheets of Al foil over the surface of a 96-well PCR plate and carefully marking the location of the centre of each well on the foil using a marking pen. The foil was transferred to the plastic lid from an empty pipette tip box to provide structural support. Each pen mark was carefully widened using a small stick to create a divot just large enough to hold one of the 3/32" diameter metal ball bearings that are placed in the bottom of the root growth plates.