THE TRANSMITTING TRACT IN GLORIOSA-SUPERBA - STRUCTURE, PISTIL EXUDATE AND POLLEN-TUBE GROWTH

The structure of the pistil exudate, transmitting tissue and pollen tu be growth of Gloriosa superba L. were studied. Flowers are protogynous , as the stigmas become receptive one day prior to anther dehiscence, and remain receptive for at least four days. Neutral red and auramine O proved to be useful for the indication of stigma receptivity, The st igma is wet while the papillae and canal cells form slight interior ce ll wall ingrowths reminiscent of transfer cells. Pistil exudate is mos tly lipidic, confirmed by the prevalence of endoplasmic reticulum in t he cytoplasm. The canal exudate includes substances derived from degen erating canal cell walls and lipid-like vesicles breaking down into fi ne fibrillar matter possibly associated with the pollen tube cell wall . Pollen tubes grow in close association with the stylar secretion, re aching most ovules, even though pollen tube numbers decrease on their way down the stylar canal. Callose deposition in the nucellus of some self-pollinated ovules could be indicative of a partly pre-zygotic gam etophytic self-incompatibility system.