Apical pattern of fruit production in the racemes of Ceratonia siliqua (Leguminosae: Caesalpinioideae): role of pollinators

Abstract

Fruit production and arrangement within the raceme were studied in two dioecious populations of Ceratonia siliqua (Leguminosae: Caesalpinioideae), an arboreal species that produces caulogenous racemes (emerging only from the old branches) with numerous flowers. Fruit production per raceme was low and similar between years and populations and even between individuals. During flowering, there were considerable flower losses from predation and lack of pollination. A mean of nine flowers per raceme began the transformation into fruits, of which 77% aborted. The final fruit production per raceme increased significantly following hand pollination, but was always very much lower than the availability of flowers in the raceme. The results suggest that fruit production of each raceme is limited by both availability of resources and a deficient pollination. In racemes setting fruit arrangement follows a definite pattern that remains constant between years and populations: fruit production was significantly higher in the apical zone of the raceme and lower in the basal zone. The pollinators of C. siliqua (flies and wasps) showed a clear preference for beginning their visits at the apex of a raceme. As a result, the pollen load deposited on the stigmas decreased from apex to base of the raceme. In most of the flowers situated in the central and basal zone of the raceme, the number of pollen grains deposited on their stigmas was lower than the number of their ovules. The high number of seeds in developed fruits suggests that the plant selectively aborts flowers that receive a smaller pollen load. The results indicate that the final pattern of fruit arrangement within the raceme is a direct result of pollinator activity.

Components of fecundity and abortion in a tropical tree, Dahlstedtia pentaphylla (Leguminosae)

“…Then dispersal distance seems to be short anyway. Predation is another factor involved in fruit abortion (Lee and Bazzaz, 1982;Augspurger, 1986;Arista et al, 1999). Although there have been observations of ants disturbing the calyx and basal stamen tube where nectar is released in D. pentaphylla, these injuries do not prevent fruit development, and are observed only in the persistent calyx of developing fruits.…”

Reproductive Ecology of Rhynchanthus beesianus W. W. Smith (Zingiberaceae) in South Yunnan, China: A Ginger with Bird Pollination Syndrome

“…Low fruit set is a common phenomenon that has been widely reported among hermaphroditic plants, and various reasons have been suggested to explain the low fruit set in plant species, such as predation, lack of pollination, or lack of resources (Berjano et al 2006). Pollination can be the first factor limiting fruit production (Schemske 1980;Howell and Roth 1981;Arista et al 1999), and the study of the reproductive ecology of flowering plants is important for determining barriers to seed and fruit set. So we decided to investigate the reproductive ecology of R. beesianus.…”

Seeds and Seedlings Production of Bioenergy Tree Species Malapari (Pongamia pinnata (L.)Pierre)

“…A greater variance of fruit set over years may occur when pollination was carried out by the majority of floral visitors [19]. In general, fruit set is influenced by many factors of environments, breeding system evolution, pollination system and biogeography [19,20]. The periods of each stage of flowering and fruiting development located in the west and east of the branches did not show a significant difference following paired t-test (P > 0.05) ( Table 4).…”