Glandular Trichomes of Fagonia L. (Zygophyllaceae) Species: Structure, Development and Secreted Materials

• Published in: Annals of botany Vol. 77; no. 1; pp. 25 - 34
• Main Authors: FAHN, ABRAHAM, SHIMONY, CARMELA
• Format: Journal Article
• Language: English
• Published: Elsevier Science Ltd 1996; Oxford University Press; Academic Press
• Subjects: adaptation; adaptation to desert conditions; cell division; cell growth; cell ultrastructure; Cell walls; Cytoplasm; developmental stages; Epidermal cells; Fagonia; fagonia arabica; fagonia glutinosa; fagonia mollis; Fluorescence; glandular trichomes; Leaves; lipophilic secretion; Materials; Mesophyll cells; plant development; plant morphology; Plants; polysaccharides; secreted material; secretion; Secretory cells; secretory granules; species; species differences; stalk; subepidermal chamber; Trichomes; xerophytes; Zygophyllaceae; Israel; subepidermal chamber; glandular trichomes; stalk; fluorescence; adaptation to desert conditions; Fagonia; secreted material
• ISSN: 0305-7364; 1095-8290
• DOI: 10.1006/anbo.1996.0004

The glandular trichomes of
Fagoniaconsist of one secretory cell and a multicellular stalk, which develops by division, elongation and elevation of epidermal cells. The latter become seperated from the mesophyll and a subepidermal chamber is formed. The length of the stalk, which differs in the various species or varieties is determined by the number of cell divisions and /or the extent of cell elongation. Although the basic morphology and development of the trichomes of the species and varieties examined are similar, two types of mature trichomes can be distinguished: one occurs in the two examined varieties of
F. mollisand the second in
F. glutinosaand
F. arabica. The secretory cells of the second type possess a very thick wall and bear a porous cupule on their top. Histochemical tests revealed that the sticky substance secreted by the secretory cells contains mainly polysaccharides and lipophilic compounds. The secreted material exhibits autofluorescence. In
F. mollisvar.
hispidachanges in the amount and shape of the fluorescent material inside the secretory cell, during the course of development, have been observed. The contribution of the glandular trichomes in
Fagoniaspecies to survival in hot desert conditions is discussed.