Mucilage‐producing Cells in the Seed Coat of Plantago Ovata: Developmental Fine Structure

Abstract

As the ovule of Plantago ovata matures into a seed its epidermal cells are transformed from undifferentiated parenchyma to thin‐walled containers of almost pure mucilage. During this process the volume of the cells increases 60–80 fold, and the protoplast degenerates to a remnant. Rapid cell expansion begins with pollination and is accompanied by an increase in the size of the nucleus and nucleolus, a change in the random arrangement of ribosomes, a decrease in the thickness of cell walls, and synthesis of starch. Deposition of mucilage inside vacuoles and between the plasma membrane and cell wall accompanies a marked increase in the number and size of Golgi vesicles. Histochemical evidence using the thiocarbohydrazide‐osmium vapor method shows polysaccharide to be present within Golgi vesicles while they are still attached to the Golgi apparatus. Mucilage deposition is associated with further cell expansion, separation of the protoplast from the cell wall, fusion of vacuoles and extra protoplasmic space, and the disappearance of starch.

Ontogeny of solasodine-containing mucilage layer inSolanum viarum Dunal, ploidy types

“…The presence of electron dense clumps was observed only at this stage. A similar pattern of development and differentiation of mucilage-secreting epidermal cells of the seed coat has been reported in Plantago ovata by Hyde (1970). He found rapid cell expansion, increase in nuclear and nucleolar size and accumulation of starch, followed by deposition of mucilage inside the vacuoles.…”

Differentiation of Mucilage Secretory Cells of the Arabidopsis Seed Coat

“…However, the appearance of the vesicles and fibrillar material correlates closely in time and space with the synthesis and secretion of mucilage observed by light microscopy. In addition, mucilage-producing cells in the root tips of Arabidopsis, tobacco, Trifolium pratense, and oat (Staehelin et al, 1990;Staehelin, 1992, 1995) and in the seed epidermis of Plantago ovata and B. campestris (Hyde, 1970;Van Caeseele et al, 1981) share similar ultrastructural characteristics. These data suggest that the seed coat mucilage is secreted via the Golgi apparatus.…”

Etude des modalites de la secretion de mucilage par les trichomes stipulaires de Psychotria bacteriophila (Rubiacees).

“…Les dictyosomes Tous les auteurs qui ont etudie les modalites de la secretion de mucilage par les cellules vegetales ont insiste sur le role primordial joue par les dictyosomes, aussi bien dans les cellules mucigenes des coiffes de racines (Mollenhauer et al 1961, Mollenhauer et Whaley 1963, Juniper et Roberts 1966, Northcote et al 1966, Morre et al 1966, Dauwalder et al 1966, 1969, Harris et al 1970, Rougier 1971Goff 1973, Juniper et Pask 1973, Dexheimer et al 1978) que dans les cellules muci genes des glandes digestives des plantes carnivores (Schnepf 1960, 1961, 1963, Dexheimer 1976, 1972, Vintejoux 1973, Vintejoux et Prevost 1976, les cellules muci genes d'organes specialises (Bonnot et Hebant 1970, Bouchet et Deysson 1971, 1972, 1973, Schnepf et Busch 1976 ou tout autre type cellulaire produisant du muci lage (Hyde 1970, Vian et al 1970, Tourte 1972 Chez le Psychotria bacteriophila, les modalites de la secretion sont assez diffe rentes, bien que la quantite de mucilage exude soit tout aussi importante et que les dictyosomes jouent aussi un role essentiel dans la synthese des polysaccharides du mucilage.…”