Figure 1.

(A) CAB expression is increased in dark-grown tir3-1 seedlings. Five micrograms of total RNA from 5-day-old dark-grown seedlings was probed with a CAB2 cDNA. To confirm equal loading, the blot was stripped and re-probed with an 18S rRNA gene. (B) doc1-1 inflorescence stems are deficient in polar auxin transport. Twenty-five millimeters of stem was excised, and the apical end was placed in nutrient solution containing 1 μM ¹⁴C-IAA ± NPA for 18 h. The basal end of the inverted segments was placed in nutrient solution where indicated. The amount of radioactive IAA (CPM) transported to the basal end of the stem was assayed by liquid scintillation. Each column represents the mean of 10 stem segments. The average of three stem segments was used for the control columns. Bar, SEM.