Nectary structure and ultrastructure

It is easy to define nectaries from a functional point of view: they are plantsecreting structures that produce nectar, but it is difficult to provide a general definition. From the anatomical point of view nectaries vary widely in ontogeny, morphology, and structure (Fahn, 1979a, 1988; Durkee, 1983; Smets et al., 2000), both between species and within species, depending on flower sexual expression or flower morph in heterostylous and heteroantheric species (Nepi at al., 1996; Küchmeister et al., 1997; Fahn & Shimony, 2001; Pacini et al., 2003). Intraspecific morphological differences exist between flowers of the same plant and between plants of the same species with different ploidy (Davis et al., 1996), and morphological characters may be nean shrub community was largely shaped by phylogenetic and climate constraints. In the course of the flowering season (spring-summer) stomatal opening and nectary size decreased, thus minimizing nectar flow at a time when water was scarce. They hypothesized that very concentrated nectar was secreted via large modified stomata, whereas cuticular secretion was mainly encountered in species with very thin nectars. Petanidou (2007) speculates that the frequency of species with stomatal nectar secretion should be much higher in hot and arid climates like the Mediterranean and deserts than in temperate ones. © 2007 Springer. All rights reserved.