Temporary incidence of polygamomonoecy in the biodiesel plant <i>Jatropha curcas</i> L. is associated with style polymorphism promoting automatic self-pollination

Abstract

Polygamomonoecy – the occurrence of perfect flowers alongside staminate and pistillate ones – in the monoecious biodiesel plant Jatropha curcas L. was reported as rare and often dismissed as having no specific functionality. Here we report that the incidence of perfect flowers is almost exclusively limited to a short period at the beginning of the blooming season and is directly associated with stigmas bending over fertile anthers, as early as in the mature bud stage. All perfect flowers have bent stigmas, while this trait is completely absent from female flowers produced later in the blooming season. In light of this species’ self-compatibility, we suggest that the occurrence of perfect flowers with bent stigmas promotes automatic self-pollination, thus enhances reproductive success when conditions are unfavourable for pollination.