Fig. 9.

Effect of sucrose concentration on phellogen and aerenchymatous phellem (AP) formation in seedlings pinched at epicotyls. Soybean seedlings were grown under drained soil conditions. When unifoliate leaves were fully expanded, an incision was made in the epicotyl of each seedling at 2 cm above the cotyledon. The cut surfaces were treated with different concentrations of sucrose, following which seedlings were grown under waterlogged conditions for 7 d. Cross-sections were taken at 1 cm above the soil surface from seedlings under each condition. Area ratios of phellogen [PH; (A)] and AP (B) to stele were calculated. Values are means ± SD (n = 3). The area ratio of phellogen showed equal variances and normal distribution. The area ratio of AP showed unequal variance and a normal distribution. Different letters indicate significant differences among all conditions (P < 0.05, one-way ANOVA followed by Tukey’s HSD post-hoc test in phellogen or Kruskal–Wallis analysis in AP for multiple comparisons).