THE TAPETUM AND SYSTEMATICS IN MONOCOTYLEDONS

Citation
Ca. Furness et Pj. Rudall, THE TAPETUM AND SYSTEMATICS IN MONOCOTYLEDONS, The Botanical review, 64(3), 1998, pp. 201-239
Citations number
81
Categorie Soggetti
Plant Sciences
Journal title
ISSN journal
00068101
Volume
64
Issue
3
Year of publication
1998
Pages
201 - 239
Database
ISI
SICI code
0006-8101(1998)64:3<201:TTASIM>2.0.ZU;2-8
Abstract
This paper critically reviews the homologies and distribution of tapet um types in monocotyledons, in relation to their systematics. Two main types of tapetum are widely recognised: secretory and plasmodial, alt hough intermediate types occur, such as the ''invasive'' tapetum descr ibed in Canna. In secretory tapeta, a layer of cells remains intact ar ound the anther locule, whereas in the plasmodial type a multinucleate tapetal plasmodium is formed in the anther locule by fusion of tapeta l protoplasts. In invasive tapeta, the cell walls break down and tapet al protoplasts invade the locule without fusing to form a plasmodium. When examining tapetum type, it is often necessary to dissect several developmental stages of the anthers. Secretory and plasmodial tapeta a re both widely distributed in monocotyledons and have probably evolved several times, although there may be some systematic significance wit hin certain groups. Among early branching taxa, Acorus and Tofieldia h ave secretory tapeta, whereas Araceae and Alismatales are uniformly pl asmodial. The tapetum is most diverse within Commelinanae, with both s ecretory and plasmodial types, and some Zingiberales have an invasive tapetum. Lilianae (Dioscoreales, Liliales, and Asparagales) are almost uniformly secretory.