Figure 1.
Natural variation in root system morphology among Arabidopsis accessions. (A) Primary root length of Arabidopsis seedlings at 9 dag, grown in 8 h dark-16 h light cycle on 0.5× MS medium. n ≥ 10. (B) Representative seedlings of the Uk-1 and Sav-0 accessions, and a seedling resulting from introgression of the Uk-1 short-root phenotype into an Sav-0 background (brxS), 9 dag grown in constant light on 0.5× MS medium containing 0.3% sucrose. Bar, 1 cm. (C) Primary root length of plants of the three genotypes grown in constant light on 0.5× MS medium containing 1.0% sucrose, 21 dag. n = 6. (D, top) Representative rosette phenotypes of the three genotypes at 24 dag, grown on soil under constant illumination. (Bottom) Root system belonging to the shoots shown in the top panel, dug out from the soil and cleaned. Bar, 1 cm. (E) Approximate primary root length of plants of the three genotypes grown on soil under constant illumination, 24 dag; n ≥ 7. (F) Transverse cryosection through the mature part of a primary root of a 7-day-old Uk-1 seedling. (ep) epidermis; (co) cortex; (en) endodermis. (G) Relative response of Col, Sav-0, Uk-1, and brxS seedlings to different exogenous plant hormone applications, 6 dag. Seedlings were grown in constant light on 0.5× MS medium containing 2.0% sucrose plus indicated hormone supplement. (IAA) indole acetic acid; (NAA) naphtalene acetic acid; (GA) gibberellic acid; (BA) benzylaminopurine. Error bars are standard error.