Functional dioecy in Gleditsia amorphoides (Fabaceae)

CERINO, MARÍA CAROLINA; CASTRO, DAMIÁN CÉSAR; RICHARD, GERALDINA ALICIA; EXNER, ELIANA DE LUJÁN; PENSIERO, JOSÉ FRANCISCO

AUSTRALIAN JOURNAL OF BOTANY

CSIRO PUBLISHING

Año: 2018 vol. 66 p. 85 - 93

0067-1924

The genus Gleditsia (Fabaceae) comprises woody shrubs and trees that grow in temperate and subtropicalregions around the world. This genus is characterised by sexual polymorphism and functionally unisexual flowers. Gleditsiaamorphoides is the southernmost species of the genus, and is widely used as a source of timber and derived products forindustrial applications (galactomannans are extracted from its seeds and saponins are derived from its fruits). The speciesis endemic to the Chaquenean Forest of South America. It is described as morphologically androdioecious, with male andperfect flowers appearing on different plants. In the current study, we characterised floral morphology, experimentallytested the breeding system and analysed flower visitors. Results indicated that G. amorphoides staminate flowers produceviable pollen grains and that perfect flowers have a functional gynoecium and empty anthers, where pollen abortionoccurs early in floral development. The species relies on outcrossing, which depends mainly on pollen carried by insectpollinators, to produce seeds and fruits. We conclude that G. amorphoides is functionally dioecious, with staminate andpistillate floral morphs.