Figure 1. The “compact root architecture 2” (cra2) mutants have short roots and more lateral roots independently of the growth conditions.

A and B, Representative examples of wild-type (WT) and cra2-1 plants that were grown in the greenhouse for one month on a perlite-sand mixture (A) or for three months on soil (B). Bar  = 1 cm in A, 10 cm in B. C, Quantification of the stems, pods and seeds dry weight of the WT, cra2-1 and cra2-2 plants that are shown in (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). D, Quantification of the root length (upper graph), lateral root number (middle graph) and lateral root density (lower graph) of the WT, cra2-1 and cra2-2 plants that were grown in vitro for 10 days post-germination (dpg) on an N-deprived “i” medium [42]. 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). E, Representative examples of the WT and cra2-1 plants that were grown in vitro for three dpg on an N-deprived “i” medium [42] or for 14 dpg on the same medium (- N), on an N-rich medium (+N, Fahraeus with NH₄NO₃ 10 mM; [43]), or on an N- and C-rich medium (+N+C, “Lateral Root Inducing Medium; [42]). Note that in cra2, 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.