Stigma, Style, and Obturator of Ornithogalum Caudatum (Liliaceae) and Their Function in the Reproductive Process

Abstract

Transmitting tissue in Ornithogalum is divided into three regions corresponding to classical divisions of the gynoecium: stigma, style, and ovary. The stigma differentiates from epidermal cells of the stylar apex. These cells form the stigmal papillae and have dense cytoplasm with abundant ER and lipid bodies. Papillae have walls with small transfer‐ingrowths. At floral receptivity, papillae secrete a small amount of surface exudate. Epidermal cells of the style contain numerous spherosomes and have thin filaments of cytoplasm traversing the central vacuole. The stylar cortex is composed of 3‐6 layers of parenchyma cells which contain numerous spherosomes and often have secondary vacuoles. Vascular tissue in the style consists of one collateral bundle in each lobe. Cells of the epidermal layer lining the stylar canal are secretory. They are initially vacuolate but fill progressively with dense cytoplasm as their secretory activity increases. Secretory activity occurs in three phases, each characterized by a particular organelle population and secretory product. At anthesis, the canal is filled with an exudate consisting of carbohydrate, protein, and lipid. In the ovary, the obturator differentiates from cells at the base of the funiculus and the tip of the carpel margins. It forms a pad of tissue which covers most of the former placenta. The obturator is secretory and produces a surface exudate. We believe our observations on Ornithogalum support the hypothesis that all transmitting tissue is of the same morphological origin and that it provides nutritive and chemotropic factors for pollen tube growth.

Stigmatic surface in the Vochysiaceae: reproductive and taxonomic implications

“…Different kinds of style may be present in the same group, as in the Caesalpinioideae (Owens 1989) and they may not be that different in their basically secretory nature. As for the species studied, the style is solid, filled by a secretory transmitting tissue, which shows a continuity between the stigma and the placentary obturator, similar to that described for Ornithogalum caudatum (Liliaceae) (Tilton & Horner 1980). The different types of stigma can be related to incompatibility mechanisms (Heslop-Harrison 1975).…”

Stigma, Style, and Pollen Recognition inGalinsoga QuabriradiataRuiz & Pav. (Compositae)

“…et al (1976) reported the absence of lipids from the exudate of Lycopersicon, lipids do occur in minor amounts in Malus (CREST! et al 1980), and are significant components of the stylar exudates of Forsythia (DuMAS 1974(DuMAS , 1977, Ornithogalum (TILTON and HoRNER 1980), Citrus (CIAMPOLINI et al 1981), and of Galinsoga, as reported here.…”

“…(1976); CLARKE and KNOX (1978); FERRARI et al (1981); MAscARENHAS and MARMELSTEIN (1981); HrNATA et al (1982) and NrsHio and HrNATA (1982). Many pubblications intervene between the anatomical and molecular ends of the spectrum, and these are reviewed by, or included in, the works of HANF (1935); VASIL and }oHRI (1964); HESLOP-HARRISON and SHIVANNA (1977), TILTON and HoRNER (1980), and HESLOP-HARRISON (1981).…”

Morphoanatomy and ontogeny of fruit in Bromeliaceae species

“…Thus, the syncarpy character is highly relevant for group taxonomy in delimiting the subfamilies, so that, considering the new phylogeny of the family (Givnish et al 2007), its detailed (Tilton & Horner 1980). Sajo et al (2004b) cited the presence of this tissue in the placental region, but did not describe it.…”