ACC Treatment Can Partially Suppress Tropism Defects of d6pk Mutants.
(A) Representative photographs of three 5-d-old wild-type and mutant seedlings grown in the absence and presence of 0.2 µM ACC and exposed to unilateral white light (100 µmol m−2 s−1) for 20 h. Bar = 5 mm.
(B) Quantification of hypocotyl bending in 5-d-old etiolated seedlings as shown in (A).
(C) Quantification of negative gravitropism of the hypocotyls of 5-d-old seedlings. Each segment corresponds to a 30° angle window.
(D) Quantification of graviresponse of 5-d-old wild-type and mutant seedlings grown in the dark in the absence or presence of 0.2 µM ACC. Hypocotyl gravitropism was determined 24 h after changing the gravity vector by 90°.
In (A), (B), and (D), the agravitropically growing seedlings were reoriented toward the gravity vector in safe green light before phototropism response ([A] and [B]) and graviresponse (D) experiments were initiated. Average and sd were determined from at least 12 seedlings. Student’s t test, compared with Columbia (Col) unless otherwise indicated by brackets: *0.01 < P < 0.05; **0.001 < P < 0.01; ***P < 0.001.
[See online article for color version of this figure.]