Fig. 4

Transmission electron micrographs of husk and caryopsis cuticles at regions of poor adhesion. a Inner surface cuticle of a palea at GS 51 grown in cool conditions. The cuticular layer (solid black arrow) often began to detach from the underlying cell wall (detachment shown by black and white arrow) at the corners between adjacent epidermal cells. b Region of separation between the husk (lemma) and pericarp at GS 85. The cementing layer does not fill the entire space between the pericarp and the husk, evidenced by gaps in the cementing material (black arrow). The interface between the pericarp cell wall and the pericarp cuticle is not smooth, but does not show globular deposits of cutin (black and white arrow). A thin, electron-lucent outer cuticle separates the pericarp cuticle from the electron-dense cementing material (white arrow). c Caryopsis at GS 85 from CC treatment. The surface cuticles of the husk and caryopsis are separated (black arrow). The underlying cuticular layer of the pericarp has a slightly flocculate appearance (black and white arrow) with electron-dense lamellae in the cuticle proper (white arrow). At the point of separation, these lamellae are not all in parallell, but occur at several orientations. Lamellae do not occur on the inner cuticle of the lemma. d Tubelike cell at a region of separation between the husk and caryopsis (black arrow) at GS 85 in a CC grain. CC = cell corner, Le = lemma cell wall, Pe = pericarp cell wall, T = tubelike cell