Figure 1.

A, Ectopic branch root patterning of maize plant observed in the University of Missouri planting fields after infestation by D. v. virgifera. B and C, Photographs of healthy and damaged nodal roots. Loss of lateral root spatial symmetry is noted when roots were damaged by herbivore feeding. D and E, Root radiographic images showing [¹¹C]photosynthate distributions in healthy (D) and damaged (E) nodal roots. Images were acquired 90 min after administration of a dose of ¹¹CO₂ to a source leaf. ¹¹C activity shows good spatial correlation with sites of LRP, suggesting these are sites are strong sinks with high metabolic activity. F, Root radiographic image acquired after a subcortical injection of [¹¹C]IAA into a healthy undamaged root—a similar symmetrical spatial patterning of ¹¹C tracer binding is seen between this image and the healthy undamaged root image presented in D for [¹¹C]photosynthate. G, Root radiographic image acquired after a subcortical injection of [¹¹C]IAA into a WCR-damaged root—a similar nonsymmetrical spatial patterning of ¹¹C tracer binding is seen between this image and the damaged root image presented in E for [¹¹C]photosynthate. The spatial correlations of ¹¹C radioactivity seen between [¹¹C]IAA and [¹¹C]photosynthate images suggests that LRP are sites of high auxin receptor density.