F. Ciampolini

Ultrastructural and histochemical features of pistil of Malus communis: The stylar transmitting tissue

Abstract The structural and histochemical features of the stylar transmitting tissue of Malus communis were investigated by light and transmission electron microscopy. The transmitting tissue of apple is composed of cells and intercellular substance. The cells are very rich in cytoplasm and are characterized by numerous large rough endoplasmic reticulum (RER) cisterns, and by large Golgi vesicles rich in polysaccharides. The intercellular substance, probably secreted by transmitting tissue cells, contains proteins and polysaccharides. A possible role of the intercellular substance in the incompatibility reaction is discussed.

Intranuclear crystalloids in leaves and styles of Linaria vulgaris mill

Unusual intranuclear inclusions present in the parenchymatic cells of leaves and styles of Linaria vulgaris are described. These inclusions are composed of layers of tubules spaced 9–10 nm apart. The direction of the tubules in each layer is offset 60° with respect to the tubular direction in the adjacent layers. The diameter of the tubules (23–26 nm) suggests a similarity to the cytoplasmic microtubules. The high degree of molecular order in these structures allows discrete optical diffraction to 7 nm. These intranuclear microtubular crystalloids, as already reported for other such crystalloids, have close associations with the nucleoli.

La componente lipidica dell'essudato stigmatico di Citrus limon (L.) Burm

Abstract The lipidic component of Citrus limon (L.) Burm. stigmatic exudate. Chromatographic methods (Gas Chromatography and Thin Layer Chromatography) were used to investigate the lipids present in the stigmatic secretion of Citrus limon. 12 fatty acids, ranging from C 12 to C 24, were identified; they form 7 classes of different lipids, 3 of them having unsaturated components.

Alcuni cenni sulla biologia del polline

SummaryIn the present paper some data on the pollen biology are reported. The current knowledge on the pollen development, pollen dispersion in the wind pollination are shortly described. The chemical composition of some pollen grains are also reported.RiassuntoNel presente lavoro vengono riportati alcuni brevi cenni sulla biologia del polline. Viene descritto il processo di formazione del granulo pollinico e la sua dispersione con particolare riguardo alle piante anemofile. Vengono brevemente riportati anche alcuni dati sulla composizione chimica del polline.