Possible functions of the petal hairs of Jodina Hook. & Arn. ex Meisn. (Cervantesiaceae) during pollination

Abstract

Jodina (Cervantesiaceae, Santalales) is a South American monotypic genus of hemiparasitic trees that occurs mainly in xeric and semi-xeric habitats. The genus is characterized by its rhombic, glabrous and stiff leaves. The flowers are monochlamydous and the petals give rise to long hairs arranged behind the stamens. It has been mentioned that these hairs could play a role during pollination nevertheless no information is recorded for Jodina or other members of Cervantesiaceae. The goals of this study were: (1) to deepen the anatomical analyses of the petal hairs and the disc, including chemistry; (2) to ascertain the possible role of the petal hairs during pollination. Flowers in different stages of development were collected in natural populations of Argentina and processed for LM and SEM analyses. Additionally, an olfactory test was conducted. We observed that, as the flower opens, the hairs enter the thecae and emerge with pollen grains adhered at their tips. The petal hairs contain proteins and lipids. They also stain light red with neutral red and emit a delicate pleasant fragrance. During field trips two species of Diptera were observed visiting the flowers. The findings let us to suggest a possible role of the petal hairs as osmophores to attract insects and as a reward for pollinators.