Nectary structure and ultrastructure in two floral morphs of koelreuteria elegans subsp. formosana (sapindaceae)

• Autores: Ávalos, Adán Alberto; Lattar, Elsa Clorinda; Galati, Beatriz Gloria; Ferrucci, María Silvia
• Año de publicación: 2017
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Flora, 2017, vol. 226, p. 29-37.
• Materia: Ultrastructure; Koelreuterieae; Flower nectary; Nectarostomata; Nectar secretion
• Institución: Universidad Nacional del Nordeste

Fil: Ávalos, Adán Alberto. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentina.
Fil: Ávalos, Adan Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica del Nordeste.
Fil: Lattar, Elsa Clorinda. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; Argentina.
Fil: Lattar, Elsa Clorinda. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica del Nordeste; Argentina.
Fil: Galati, Beatriz Gloria. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; Argentina.
Fil: Ferrucci, María Silvia. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; Argentina.
Fil: Ferrucci, María Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica del Nordeste: Argentina.
The structure and ultrastructure of the floral nectary of staminate and pistillate flowers of Koelreuteria elegans subsp. formosana (Sapindaceae, Koelreuterieae) were studied. In both floral morphs, the floral nectary is extrastaminal, receptacular, thimble-shaped and persistent. The anatomical analysis revealed a differentiated secretory parenchyma and a less developed, inner non-secretory parenchyma. These anatomical features reveal that the nectary is structured, and is supplied by phloem traces derived from the central stele. In the middle of the floral nectary there are few modified stomata. The nectarostomata were of anomocytic type;they may occur atthe level of or sunken below the adjacent epidermal cells. Sta tistically significant differences were observed between both floral morphs in relation to nectar volume and the different moments of day, whereas the sugar concentration showed no significant differences. Ultrastructural studies showed no difference between staminate and pistillate flowers. At anthesis, amy loplasts and lipid globules were observed in the secretory parenchyma cells, whereas at post-anthesis the secretory parenchyma cells were degenerated. Floral nectar is secreted through nectarostomata and the outer epidermal cell walls. These results are discussed in relation to other species belonging to different tribes within Sapindaceae