Figure 5.

Distinct Effects of CA-rop2 and DN-rop2 Expression Distinguish the Rop-Dependent and Rop-Independent Phases of Anisotropic Cell Expansion.

(A) A “pseudo-time-course” analysis of radial and longitudinal expansion was conducted on hypocotyl cortex cells. The fifth cortex cells from three adjacent files were used in this analysis. Changes in cell expansion on these cortex cells were followed from days 1 to 5 after germination.

(B) and (C) Changes in average lengths and widths of hypocotyl cortex cells from days 1 to 5 after germination (n = 32). The cortex cells displayed their most rapid cell expansion in both the radial and longitudinal directions during days 2 and 3, although preferential expansion occurred in the longitudinal direction. Statistical analysis (t test) showed that during this period, longitudinal expansion was inhibited significantly by DN-rop2 expression, whereas radial expansion was promoted significantly by CA-rop2 expression (P ≤ 0.05). After day 3, only longitudinal expansion was observed, and neither radial nor longitudinal expansion was affected significantly by CA-rop2 or DN-rop2 expression.

WT, wild type.