BREEDING SYSTEM IN FICUS CARICA, THE COMMON FIG. II. POLLINATION EVENTS

Pollination events are examined in Ficus carica , the common fig. The stigma of the long‐styled female flower is wet. Stigma and stylar secretions consist of mucopolysaccharides, lipids, and insoluble carbohydrates. The pollen from anthers of the male flowers is dimorphic, being tri‐ and diporate. Pollen tubes grow in intercellular secretions of the solid style until they reach the obturator which forms on the funiculus of the ovarian cavity. The obturator secretes primarily insoluble carbohydrates which remain sequestered under the cuticle. A pollen tube grows through the stylar tissues emerging beneath the cuticle of the obturator into these secretions and then penetrates the micropyle. Differences were observed between timed pollination trials in two sites in California. At one site, a characteristic coiling of pollen tubes occurred in the region of the funiculus before pollen tube penetration of the micropyle. At the other site, presyngamy pollen tube coiling was not observed and pollen tube growth rates were doubled. There were higher temperatures at the second site during the pollination experiment. The stigma of the short‐styled flowers is nearly dry, and the transmitting tract shows decreased amounts of secretion. The funiculus did not have a differentiated obturator and secretions there were insufficient to raise the cuticle over the micropyle. The short‐styled flowers appear to be losing their ability to function as fully viable females.