Selenicereus grandiflorus

Flower and study material

The 2001 study examined flowers of Selenicereus grandiflorus collected in Veracruz, Mexico, in 1997. Material represented developmental stages from 2 cm buds to 15 cm open flowers. The white flower opens at night, and tissue emitting a sweet scent lies on the inner surface of the lower part of the floral tube. [Mosti et al. 2001, pp.194–195]

The secretory cell

Electron microscopy showed progressive enlargement of the cells and their vacuoles. Elements of the smooth endoplasmic reticulum fused with the vacuolar membrane and delivered lipid material into the vacuole. At flower opening, the large vacuole occupied almost the entire cell interior. Loss of the nucleus and reduction of the cytoplasm formed part of the final developmental stage of this tissue. [Mosti et al. 2001, pp.199–200]

Secretion and scope of inference

The authors described holocrine secretion, in which the product is released as the cell breaks down. Formation of subcuticular spaces also indicated an additional secretion route. Chromatographic analysis detected guaiacol and allyl-syringol among other compounds. Later-eluting compounds were tentatively identified as long-chain hydrocarbons, alcohols and ethers. [Mosti et al. 2001, pp.199–201]

The paper provides direct observations of cells and extract composition. The authors propose that pollinator contact mechanically releases the secretion and that moths pollinate the flowers on the basis of floral traits. These elements were not tested by visitor observations or pollinator-exclusion experiments. [Mosti et al. 2001, pp.201–202]