Structure, ontogeny and histochemistry of cyathial nectaries in Euphorbia heterophylla L. (Euphorbiaceae)

Abstract

The mature cyathial nectary of <i>Euphorbia heterophylla</i> L. consists of distint secretory and sub-secretory zones. The secretory zone consists of 1-3 layer of palisade-like epidermal cells, supplied by both phloem and xylem. Distinct 'secretory pits' surrounded by thin cuticle are present in the secretory tissue. Enzymes such as succinic dehydrogenase and acid phosphatase were localized. Probable functions of cyathial nectaries and animal visitors are discussed.