Figure 3.

In Seedlings, PGX3 Functions in Root Elongation and Regulates Cotyledon Shape, Stomatal Spacing, and Stomatal Pore Size.

(A) Primary root length of 4- to 8-d-old light-grown seedlings in Col and pgx3-1. Error bars are se (n ≥ 91 seedlings per genotype per day from three independent experiments; ***P < 0.001, Student’s t test). Relative growth rates (RGRs) of roots in each genotype are indicated in the graph.

(B) and (C) Cotyledon shape of 6-d-old pgx3-1 mutants. Panels show representative images (B) and quantifications (C) (n ≥ 107 seedlings per genotype from three independent experiments).

(D) and (E) Stomatal cluster analysis in cotyledons of 6-d-old Col and pgx3-1 seedlings. Panels show representative PI staining (D) and quantifications (E) (n ≥ 271 stomata from 12 seedlings per genotype, two independent experiments; ***P < 0.001, χ² test). Red brackets in (D) indicate clustered stomata.

(F) Stomatal dimensions. Shown are brackets representing pore length (1, blue), pore width (2, magenta), and guard cell pair height (3, green) along with representative PI staining images of stomata in 6-d-old seedlings of Col, pgx3-1, PGX3 comp #3, and PGX3 OE #7.

(G) to (J) Measurements of pore length (G), pore width (H), guard cell pair height (I), and the ratio of pore length to guard cell pair height (J) in 6-d-old Col, pgx3-1, PGX3 comp #3, and PGX3 OE #7 seedlings. Numbers in black boxes on the graphs correspond to numbers in stomatal dimension legend in (F). Error bars are se, and lowercase letters represent significantly different groups (n ≥ 140 stomata from at least 10 seedlings per genotype, two independent experiments; P < 0.05, one-way ANOVA and Tukey test).

Bars = 1 mm in (B), 10 µm in (D), and 5 µm in (F).