The Ultrastructure of Glandular Trichomes ofPhillyrea latifoliaL. (Oleaceae) Leaves

Abstract

Abstract The anatomy and ultrastructure of glandular trichomes at different developmental stages were investigated in Phillyrea latifolia L. leaves by transmission electron microscopy and histochemical techniques. The trichome consisted of a multicellular secretory head, a unicellular stalk and a collecting cell surrounded by epidermal cells and spongy mesophyll cells. There were numerous plasmodesmata across the cell walls of trichome cells, and especially between the stalk cell and the collecting cell. The collecting cell and stalk cell contained few chloroplasts. Mitochondria, elements of the endoplasmic reticulum and small vacuoles were abundant in the secretory cells. Crystals were present in the secretory cells and the collecting cell, especially at the mature and senescent stages of trichome development. As the cuticle, which covered the secretory cells, did not show pores or perforations, it is proposed that secretion occurred by accumulation of products in subcuticular spaces followed by diffusion through the cuticle. Callose accumulation was observed between the stalk cell and the collecting cell of senescent trichomes, especially in salt-treated plants. Trichome ontogeny was accelerated in salt-treated plants.