d. Average number of cell divisions along the epidermis (ep) and cortex (co) in 5 DAG old Col-0 and eir1-4 root tips 12 HAT to ammonium or nitrate supplemented media. Data are derived from n=15 and n=17 roots of Col and n=10 and n=9 roots of eir1-4 on ammonium and nitrate, respectively. Statistical significance was evaluated with ANOVA at p<0.05. The box chart components are defined as; box (25%-75%), central band (median line), central box (mean) and the range is within 1.5IQR. 