Reproductive biology of Caesalpinia calycina and C. pluviosa (Leguminosae) of the caatinga of north-eastern Brazil.

摘要

The pollination biology, breeding system and fruiting success of Caesalpinia calycina and C. pluviosa var. sanfranciscana were studied in caatinga vegetation in Bahia, NE Brazil. The principal pollinators for both species were carpenter bees. Caesalpinia calycina is andromonoecious but in C. pluviosa all flowers are hermaphrodite. In C. calycina all selfed flowers were abscised within 72 h despite rapid self-pollen tube growth to the ovary and ovule penetration. Prevention of selfing therefore seems to be controlled by a post-zygotic mechanism. Both species had very low fruit set and it is suggested that this is at least in part due to geitonogamous pollinations with ovule penetration by self pollen tubes.