Figure 6

TEM micrographs of AVIs in the adaxial epidermal cells of the inner petal region of lisianthus flowers. A. Material being deposited onto a dense AVI part (white arrowhead) from directional rupturing of electron-dense bodies (vesicles, arrow) through a loose thread network zone (double white arrowhead). Smaller electron-dense vesicles are also visible in presumed PVCs in the cytoplasm. B. Close-up image of the boxed region in A, showing a PVC containing an electron-dense vesicle, and the close proximity of the abundant ER. C. Part of an adaxial epidermal cell under high magnification, showing two PVCs (about 250 nm) containing electron-dense bodies (< 200 nm, arrow) in the cytoplasm and a small electron-dense body merging with a large electron-dense body in the central vacuole (V). Starch granule indicated by black arrowhead. D. Part of an adaxial epidermal cell, showing large electron-dense bodies (arrow) in small vacuoles prior to the release to the central vacuole (V). E. TEM image showing electron-dense bodies (arrow) and the rupturing and depositing of its contents (threads, double back arrowhead) onto the dense part (white arrowhead) of an AVI in the central vacuole (V). F. Close-up image of part of an AVI, showing a membranous or thread network and intravacuolar membrane fragments (dashed arrow). G. Close-up image of part of a rupturing electron-dense body. No membrane boundary is apparent. H. Close-up image of an electron-dense body before rupturing. No membrane boundary is apparent.