Figure 2.

SA Regulates Root Growth and Development in a NPR1-Independent Manner

(A) Representative images showing the morphological changes of Col-0 and npr1 under SA treatment. DMSO is the solvent control. Scale bars, 2 cm.

(B) SA inhibited the primary root elongation in a NPR1-independent manner. Root length of 7-day-old Col-0 and npr1 seedlings grown on MS plates with different concentrations of SA was measured. Relative length was calculated by dividing the values with the root length at SA = 0. Boxplots show the first and third quartiles, with whiskers indicating maximum and minimum, the line for median, and the black dot for mean. n = 11–28; p values were calculated by a two-tailed t test for indicated pairs of Col-0 and npr1 at a certain concentration of SA.

(C–H) SA interfered with root gravitropism independently of NPR1. Root tip angles of 7-day-old Col-0 (C–E) and npr1 (F–H) seedlings were measured and shown as polar bar charts. Two-tailed t tests were performed to indicate the difference of mean value, and F-tests indicate the difference of variances. For Col-0, SA treatments were compared with the DMSO control, and the npr1 groups were compared with Col-0 under the same SA treatment, respectively.

(I) Inhibition of lateral root formation by SA does not involve NPR1. The number of emerged lateral roots for 10-day-old plants was counted. n = 20–25. p values were calculated by a two-tailed t test.

See also Figure S1.