Embryological studies in Anredera cordifolia (Ten.) Steenis (Basellaceae)

POZNER, R.; MALDONADO, S.

Giornale Botanico Italiano

Società Botanica Italiana

Lugar: Firenze; Año: 1989 p. 39 - 48

0017-0070

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> This paper deals with the ovule and anther structure, sporogenesis and gametogenesis of Anredera cordifolia (Ten.) Steenis. The conclusions are: the anther wall develops according to the Monocotyledoneous type of Davis (1966). The tapetum is secretory and the endothecial cells develop U-form thickenings on radial and internal tangential walls. Microspore mother cells undergoe simultaneous cytokinesis, and the microspore tetrads are tetrahedral. Pollen grains are 3-celled when shed. At anthesis the ovule is orthoamphitropous, crassinucellar and bitegmic, with the micropyle formed by the inner integument. The archesporial cell cuts off a primary parietary cell wich becomes the parietal tissue. A nucellar cap develops from the nucellar epidermis. The outer integument is dermal and subdermal in origin, but the inner is only dermal. Only one archesporial cell differentiates from the nucellus, and the megaspores are arranged in T-tetrads. The chalazal megaspore produces a 8-nucleate embryo sac which develops according to the Polygonum type. The mature synergids present a filiform apparatus that accords to the type I, following Cocucci (1981). The antipodal cells are ephemeral. Starch grains accumulate in the synergids, egg cell and central cell. Finally, the systematic value for Basellaceae of the embryological characters here considered is discussed.