Osmophores of Amorphophallus rivieri Durieu (Araceae)

Abstract

The undertaken investigations (SEM, LM) concentrated on the distribution and the anatomy of osmophores emitting a characteristic odour of inflorescence of Amorphophallus rivieri Durieu. The osmophores situated at the top part of spadix (appendix), secreted a strong fragrance during the whole period of blooming, whereas those located on the stamens, in the apical and in the middle part of the spatha produced a weaker smell. The fragrance at the basis of spatha was undetectable although both the secretion and the tissue structure characteristic for osmophores located on the adaxial surface of the remaining part of the spatha were observed. The gland tissue consisted of the epidermis and of several layers of subepidermal parenchyma. The epidermis was covered by a thin, striated cuticle or sticks of wax. Moreover, there was also a small number of stomata covered with a smooth cuticle. The cells of osmophores stained intensively with neutral red. They contained numerous lipid drops, which presumably are carriers of the secreted fragrance substances. The cells of subepidermal layers were filled up with starch grains in the appendix and stamens. A considerable quantity of starch was also observed in the deeper layers of parenchyma in the spatha. The pattern of osmophores distribution corresponds with the localization of these inflorescence fragments, which emit heat, as showed in the literature.