Breeding System in Ficus Carica, the Common Fig. Ii. Pollination Events

Abstract

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.

How to be a Fig Wasp

“…We begin with an overview of pollination ecology, setting aside the antagonistic (8,50,197). For example, egg-laying by pollinators is closely synchronized with the receptivity of fig flowers, and the release of adults from the fig coincides exactly with pollen presentation (12,119,141). Fig phenology (24,26) and the production of fig crops (97) are also closely linked to pollinator population dynamics (5).…”

“…Style length dimorphism is a defining feature of dioecious species and separates the inflorescence types into gall figs and seed figs (13). A general picture of dioecious fig pollination has emerged after more than a century of observation (8,12,48,50,55,119,158,197). Female pollinators are attracted to both gall and seed figs (3,127,162); they pollinate both types, but their offspring only develop in gall figs (48,55).…”

“…Gall figs are functionally "male" because they foster the wasp larvae that disperse fig pollen as adults. Ovules that would otherwise produce seed instead serve to nourish wasp offspring (12,123). On the other hand, seed figs are functionally "female" because the styles are too long for ovipositors to reach the ovules, and viable seeds result from pollination.…”

Cospeciation Analysis of an Obligate Pollination Mutualism: Haveglochidion Trees (Euphorbiaceae) and Pollinating Epicephala Moths(gracillariidae) Diversified in Parallel?

“…In obligate pollination mutualisms, the pollinators are responsible for the fertilization among conspecific host flowers, and thus some adaptation in the plants to exclude nonlegitimate pollinators is likely present. In fact, there are several candidates of reciprocally selected traits that may reinforce plant-pollinator specialization, such as synchronized phenological patterns (Wiebes 1979;Beck and Lord 1988;Patel and Hossaert-McKey 2000), species-specific olfactory signals (Ware et al 1993;Hossaert-McKey et al 1994;Song et al 2001;Grison-Pigé et al 2002, 2003, and reciprocal adaptation between pollinator morphology and floral structure (Ramírez 1974;Herre 1989;Van Noort and Compton 1996;Kato et al 2003;Weiblen 2004). Thus, knowledge on the degree of cospeciation in obligate pollination mutualisms provides an essential step toward understanding the historical role of coevolution in shaping speciation and diversification in plants and pollinators.…”

Influences of presowing treatments on the germination and emergence of fig seeds (Ficus carica L.)

“…Currently, unknown genes still determine whether a seed from a single syconium will be a caprifig or an female fig. (BECK; LORD, 1988).…”