Ultrastructure of the corona of scented and scentless flowers of Passiflora spp. (Passifloraceae)

AMELA GARCÍA, M. T., GALATI, B. G. & HOC, P. S.

FLORA

Elsevier

Lugar: Jena; Año: 2007 vol. 202 p. 302 - 315

0367-2530

To know thoroughly the structure and function of the corona of Passiflora, the anatomy and ultrastructure of two species were analysed in relation to the emission of odour perceivable by humans: a scented one, P. caerulea L., and a scentless one, P. suberosa L. Both species exhibited secretory tissue, whose cells were characterised by dense cytoplasm, numerous mitochondria and vacuoles. Evidence of granulocrine secretion was detected. Nevertheless, there were differences concerning some cytological structures: P. suberosa lacked sER and starch but had large and many lipidic globules while P. caerulea had few dictyosomes, scarce lipidic content, a greater proportion of sER/rER and amyloplasts. The cellular features of P. caerulea correspond with the ones of fragrance tissues. The secretion appearance and quantity was also different between both species: P. caerulea exhibited sparse drops on the cuticle in contrast to P. suberosa, that secrets a wax-like material. If this is the final product of the secretory process or just a vehicle that contributes to the emission of volatile compounds, as occurs in certain osmophores, needs further confirmation with chemical analysis. Results are discussed in the context of the pollination syndromes of each species and their florivores.