Figure 5.

ATH1 Inhibits Cell Proliferation in the Subapical Region of the Shoot.

(A) to (D) Whole-mount staining of vascular strands of wild-type ([A] and [C]) or ath1-3 ([B] and [D]) seedlings grown in standard light ([A] and [B]) or in low light ([C] and [D]); the arrowheads mark the distance between the base of the shoot meristem and the point where the vascular strands converge at the top of the hypocotyls. hy, hypocotyl; pe, petiole.

(E) to (H) Sections through the shoot apices of seedlings comparable to those shown in (A) to (D), respectively.

(I) Cell length in the region indicated between arrowheads in (A) to (D), measured in sections comparable to those shown in (E) to (H). Bars represent averages ± sd (n = 16 to 18 for each treatment).

(J) Total length of the region between arrowheads in (A) to (D), measured in sections equivalent to those in (E) to (H). Bars represent averages ± sd (n = 4 for each treatment). Numbers over each bar are ratios between total length and average cell length.

Bars = 1 mm in (A) to (D) and 200 μm in (E) to (H).