Glandular trichomes on the inflorescence of Chrysanthemum morifolium cv. Dramatic (Compositae). I. Development and morphology

Abstract

Floral apices of Chrysanthemum morifolium cv. Dramatic form glandular trichomes on the receptacle in interfloret positions and on the corolla tube above the constriction subtended by the ovary. The glandular trichomes in both positions are initiated by the enlargement of single epidermal cells followed by a single anticlinal division and a series of periclinal divisions resulting in a 10-celled biseriate structure. Receptacular trichomes develop while florets are being initiated on the flanks of the floral apex and by the time petal primordia are initiated these trichomes are mature. Glandular trichomes on the corolla tube are initiated on peripheral florets while florets are still being initiated in a centripetal direction. Each glandular trichome has a cuticular covering beneath which secreted materials accumulate, thereby distending the cuticle. A large pore eventually forms in the cuticle and presumably allows the escape of secreted substances.