Effects of exogenous IAA and ACC on <i>ataucsia</i>-1 root growth.

<p>(A) Root phenotype of 10 days old wild-type and <i>ataucsia</i>-1 seedlings after treatment with IAA (0.03 and 0.1 µM). (B) Quantification of IAA effect on root growth. Seeds of wild-type and <i>ataucsia</i>-1 were germinated on nutrient medium for 5 days and then transferred to new medium either supplemented or not supplemented with IAA (0, 0.03 and 0.1 µM). Five days later, new root growth was evaluated. (Left) New primary root growth was measured and plotted as percentage of root growth on medium without IAA. (Right) Weight of root apparatus per cm of primary root length. (C) Quantification of ACC effect on root growth. As performed for panel B, 5 days old seedlings were transferred to medium supplemented or not with ACC (0, and 1 µM). Five days later, root growth was evaluated. (Left) Primary root growth. (Right) Two sets of y-axes are reported, on the left y-axis the weight of root apparatus per cm of primary root length and on the right y-axis the density of emerged lateral roots (number of lateral roots per cm of primary root). The values reported in B and C are means ± SE (n = 3) 15–20 seedlings per replicate. Student's <i>t</i>-test was applied. *P<0.05; **P<0.01; ***P<0.001 versus untreated seedlings or versus treated wild-type seedlings when indicated by brackets.