Soybean and Bees

An endogenous rhythm in volatile production was also demonstrated with Cestrum nocturnum
(Solanaceae) flowers (Overland, 1960). An increase in the emanation of individual aroma
compounds from flowers of some F 1
alfalfa plants, over that observed in parent plants,
suggests that total flower aroma and floral aroma character can be genetically influenced
(Loper, 1976; CHIALVA et al., 1982). It may therefore be possible to alter the floral character
of alfalfa or other plant species to increase their attractiveness to foraging honeybees
(BUTTERY et al., 1982).
Flower volatile production in a number of other plant species has been studied. Examination
of over 150 species of orchid demonstrated the existence of a complex volatile spectrum
involving approximately 50 different compounds (Dodson and Hills, 1966; Hills et al.,
1968). Floral volatile production in orchids is species specific and is instrumental in pollination
as their principal pollinators, the euglossine bees, discriminate between orchid species
by olfaction (Dodson et al., 1969; NEILAND and WILCOCK, 1998). Complex volatile spectra
have been reported for flowers from banana shrub (Michellia figo Spreng) (Toda et al., 1982),
Castanopsis caspidata Schottky (Yamaguchi et al., 1979), clovers (Trifolium spp.) (Honkanen
et al., 1969), and elder (Sambucus nigra L.) (Velisek et al., 1981).
Nectar and protection
Carbohydrates, amino acids and volatiles serve mainly in the attraction and nutrition of legitimate
nectar visitors; however, nectars also contain other compounds, for example, proteins
and several classes of secondary metabolites (ZLATKIS et al., 1973). Mentions to nectar
proteins date to the first half of last century, as described by Buxbaum (1927) and Lütge
(1961). These proteins can be source of organic nitrogen, but there are other important functions
associated with them.
For instance, the nectarins in the FN of ornamental tobacco (Nicotiana langsdorffii x Nicotiana
sanderae) are likely to protect FN from microbial infestation through the Nectar Redox Cycle
(Carter and Thurnburg, 2004; Carter et al., 2007; Park and Thornburg, 2009; Carter
et al., 2006). Anyway, FN proteomes seem to be small, as only five proteins have been found
in the FN of ornamental tobacco, eight in the FN of Jacaranda mimosifolia and ten in the FN of
Rhododendron irroratum (Kram et al., 2008), but exceptions exist as mentioned by Gonzáles-
Teuber (2009a) in Acacia myrmecophytes mutualism, where more than 50 different proteins
were identified. It is worth mentioning that this species houses ant colonies for their indirect
defence. Heil (2011) describes the majority of the nectarins as pathogenesis-related proteins,
such as chitinases, glucanases and thaumatin-like proteins.
72 SoybeAn and bees