STIGMA, STYLE, AND POLLEN-TUBE PATHWAY IN SMYRNIUM-PERFOLIATUM (APIACEAE)

Smyrnium perfoliatum has a solid style and a wet, nonpapillate stigma. The stigmatic surface coating is totally produced by the stylar transmitting tissue. The main secretion compounds are unsaturated lipids and methylesterified pectins. Lipid transport from the cells of the transmitting tissue to the extracellular space occurs by multivesicular bodies. The accumulating secretion forms an axial array of intercellular channels within the transmitting tissue. Ascending secretion forces the stigma cells to separate from each other. Pollen tubes enter the style between the stigmatic cells and grow within the secretion-filled channel.