Figure 4

Morphological and cytological characterisation of hypocotyls and trichomes. (A) Morphological comparison of the hypocotyls of WT, pPLAIIIβ-mutant, KO, OE lines, and COM. Plants were grown in MS medium for 5 d, including WT, pPLAIIIβ mutant, KO, OE1, OE2, and COM. Bar = 1 cm. (B) Cytological characterisation of the hypocotyl epidermal cells in various lines. Hypocotyl epidermal cells of WT, KO, and OE1 from 6-day-old seedlings showing reduced cell length and increased cell width in the OE plants examined by scanning electron microscopy (first row). Hypocotyl cross-sections of WT, KO, and OE plants stained with aniline blue (second row). KO plants developed longer trichome branches, whereas OE1 plants had shorter branches compared with WT (third row). Bars = 50 μm (first row) or 100 μm (second and third rows). (C) The morphological and cytological measurement of hypocotyls and trichomes. Compared with WT, KO plants developed longer hypocotyls with more epidermal cells in the hypocotyl and the trichome branches, whereas OE plants had shorter hypocotyls and trichome branches. There was no difference in cell number on the hypocotyl axis among the genotypes, but OE plants had shorter, wider epidermal cells in the hypocotyl relative to those in WT. All values are the means ± SE of 15 samples. * and ** indicate significant differences at P ≤0.05 and at P ≤0.01, respectively, by Student’s t test, compared with WT.