Handbook of palynology

Plant Breeding Systems.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1096-0031.2008.00212.x

Plant Systematics: A Phylogenetic Approach

Nectar production and presentation

The construction of classifications, as well as the understanding of biological diversity, depends upon a careful comparison of attributes of the organisms studied (Stuessy, 1990). It is widely known that data from diverse sources showing differences from taxon to taxon are of systematic significance. During the 20th century, systematists have emphasized that their discipline involves a synthesis of all knowledge (Stevens, 1994) or, in other words, the variation of as many relevant characters as possible should be incorporated into the natural system to be constructed. The extent to which particular characters are constant or labile will determine their usefulness to systematics. In general, more conservative characters will be valuable in defining families and orders, whereas more labile characters may be useful at the generic and specific levels (Webb, 1984). There is no doubt that floral characters are among the most used in the classification of flowering plants. At the same time, they constitute essential features in diagnostic keys to taxa in both taxonomic treatments and Floras (Cronquist, 1981, 1988).

A systematic survey of floral nectaries

Microsporogenesis, microgametogenesis and pollen morphology of Passiflora spp. (Passifloraceae)

Elaiophores in Gomesa bifolia (Sims) M.W. Chase & N.H. Williams (Oncidiinae: Cymbidieae: Orchidaceae): structure and oil secretion.

Flowers of Prunus persica (L.) Batch. cv. Forastero have an orange toral nectary. The nectariferous tissue was formed by densely packed parenchyma cells (secretory cells) and an epidermis with hairs and modified stomata. The epidermal cells were highly vacuolated with a striated cuticle. The ultrastructure of these cells contained a cytoplasm with endoplasmic reticulum, plastids, mitochondria and dictyosomes. Sub-epidermal cells were barely vacuolated and their ultrastructure was similar to that of the epidermal cells. Differences were observed only in the endoplasmic reticulum, which is organized in a parallel configuration. Plasmodesmata were found between adjacent secretory cells and between secretory and epidermal cells. An electron dense secretion occurred in the intercellular spaces and between the external tangential wall and the cuticle of the epidermal cells. According to the ultrastructural observations, the sugar solution could be passed through the symplast or the apoplast. The nectar could be exuded from the stomata and the micro-channels of the cuticle covering the epidermal cells.

Beatriz G. Galati

Papers

Microsporogenesis, microgametogenesis and pollen morphology of Passiflora spp. (Passifloraceae)

Elaiophores in Gomesa bifolia (Sims) M.W. Chase & N.H. Williams (Oncidiinae: Cymbidieae: Orchidaceae): structure and oil secretion.

Floral nectary ultrastructure of Prunus persica (L.) Batch cv. Forastero (Newcomer), an Argentine peach

Ultrastructure of the corona of scented and scentless flowers of Passiflora spp. (Passifloraceae)

Anatomical studies of the secretory structures: Glandular trichomes and ducts, in Grindelia pulchella Dunal (Astereae, Asteraceae)