Overview of the Arabidopsis growth experiment on soil.

Mutant lines are grown alongside their respective wildtype backgrounds on trays containing soil medium with different levels of dissolved MgSO₄·7H₂O. To control for environmental variation, each tray was divided in 8 sections, with a mutant line and its associated wildtype background line planted in alternating fashion. Yellow boxes highlight the sections with mutant plants within each flat; the other sections contain wildtype plants. For the comparison between cax1/cax3 and Col-0, 60 mM was not tested. The plants shown here are 3 weeks old and were harvested and analyzed after completing 4 weeks of growth. The experiment was repeated three times.