Fig. 4

Using the Microphenotron to screen a set of 800 molecules for effects on root system development. Sets of twelve Phytostrips filled with nutrient gel were set up in 96-well microtitre plates containing 150 µl nutrient solution per well. Arabidopsis seed was sown on the gel surface (2 seed per well) and the assay plates were placed in the plate-holders, covered with the growth boxes and transferred to the robotic platform. After 3 days, when most roots were first visible, the Phytostrips were transferred to fresh microtitre plates containing chemicals from the compound library at a starting concentration in the microtitre plate of 25 µM (final theoretical concentration after diffusion = 8.3 µM) and returned to the robotic platform. Each set of 80 chemicals from the library was assayed in duplicate plates and images from the 20 plates were captured 5–8 days after treatment and scored visually for altered root phenotypes that were seen in both replicates. The images shown were selected as representative of the range of root phenotypes observed. The treatments and the number of days after treatment (d.a.t.) that the images were captured were: a control (7 d.a.t.); b deoxycholic acid (8 d.a.t.); c abscisic acid (8 d.a.t.); d 10-hydroxycamptothecin (7 d.a.t.); e aminocyclopropanecarboxylic acid (7 d.a.t.); f sodium phenylbutyrate (5 d.a.t.); g 5α-androstanedione (7 d.a.t.); h 5,7,4′-trimethoxyflavone (5 d.a.t.); i ethionine (5 d.a.t.); j diffractaic acid (8 d.a.t.)