The “<i>compact root architecture 2</i>” (<i>cra2</i>) mutants have short roots and more lateral roots independently of the growth conditions.

<p><b>A</b> and <b>B</b>, Representative examples of wild-type (WT) and <i>cra2-1</i> plants that were grown in the greenhouse for one month on a perlite-sand mixture (<b>A</b>) or for three months on soil (<b>B</b>). Bar = 1 cm in A, 10 cm in B. <b>C</b>, Quantification of the stems, pods and seeds dry weight of the WT, <i>cra2-1</i> and <i>cra2-2</i> plants that are shown in (<b>B</b>). The error bars represent confidence intervals (α = 5%). A Kruskal and Wallis test was used to determine the significant differences (indicated by letters, α<5%; n = 10). <b>D</b>, Quantification of the root length (upper graph), lateral root number (middle graph) and lateral root density (lower graph) of the WT, <i>cra2-1</i> and <i>cra2-2</i> plants that were grown <i>in vitro</i> for 10 days post-germination (dpg) on an N-deprived “i” medium <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1004891#pgen.1004891-GonzalezRizzo2" target="_blank">[42]</a>. The error bars represent confidence intervals (α = 1%). A Kruskal and Wallis test was used to determine the significant differences (indicated by letters, α<1%; n>25). <b>E</b>, Representative examples of the WT and <i>cra2-1</i> plants that were grown <i>in vitro</i> for three dpg on an N-deprived “i” medium <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1004891#pgen.1004891-GonzalezRizzo2" target="_blank">[42]</a> or for 14 dpg on the same medium (- N), on an N-rich medium (+N, Fahraeus with NH₄NO₃ 10 mM; <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1004891#pgen.1004891-Truchet1" target="_blank">[43]</a>), or on an N- and C-rich medium (+N+C, “Lateral Root Inducing Medium; <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1004891#pgen.1004891-GonzalezRizzo2" target="_blank">[42]</a>). Note that in <i>cra2</i>, the lateral roots were already emerged at three dpg (arrowhead) and that the “compact root system architecture” phenotype was detectable independently of the growth medium. Bars = 0,5 cm.