Abstract
The stigma surface is a complex multicellular structure where the development of the pollen tube begins. This development is necessary for sucess in fertilization and depends on recognition processes that involve the anatomy of the stigma. Passiflora is an economically important genus because of its edible fruits. Many authors have described the stigma of Passiflora but nothing is known about the ontogenesis of this structure. This work aimed to describe the formation of the stigmatic surface of Passiflora elegans. Results showed that, in bud, the stigmatic surface of this species is flat with small cells. The cells in the subdermal layer have large vacuoles and the nucleus, near to the external periclinal walls. During its development the stigma surface becomes uneven due to the elongation of cells in the subdermal layer. Elongation results in an increase of external secretory surface area of the stigmas, and probably plays an important role in pollen recognition. The polysaccharide content found in the inner walls of these structures might be involved in the signal process for pollen tube growth during its early development. The morphological evidence presented here shows that, as the stigma of Passiflora is formed by dermal and subdermal cells, it should not be characterized as colleters or papillae and, therefore, it is defined here as stigma emergences.
Key-words:
anatomy; stigma development; stigma emergence; pollination