Soybean and Bees

Kram (2008) suggested a role in antimicrobial defence for the GDSL lipases (hydrolytic enzymes
with multifunctional properties) in the FN of the blue jacaranda (Jacaranda mimosifolia).
As nectars are commonly infested by microorganisms, most nectarins seem to be involved
in protecting nectar against them, particularly yeasts, whose metabolic activities
change nectar composition (Herrera et al., 2008, 2009). Nevertheless, although the presence
of some nectar-infecting microorganisms or nectar robbers might have beneficial effects
on the plant (Lara and Ornellas, 2002), Herrera et al. (2008) propose that most plants
benefit from keeping the nectar as sterile as possible, maintaining control on its chemical
composition.
Nectaries open stomata can be a point on entry of plant pathogens, as early mentioned by
Ivanoff and Keith (1941) and Keith and Ivanoff (1941). More recently, Buban et al. (2003) and
Farkas et al. (2007) describe the nectary as the primary site of infection by Erwina amylovora,
causal agent of the bacterial fire blight of apples and pears. To protect the plant, nectars
contain antimicrobial nectarins to protect the nectary tissue from infection. It has also been
observed that some nectars are toxic, due to some compounds toxic to robbers and pests, but
sometimes also to beneficials, like pollinators. The toxicity of the nectar is due to secondary
metabolites, non-proteins amino acids, phenolics and alkaloids (Baker, 1977; Adler, 2000).
Effects of nectar and pollen removal
Nectar removal by floral visitors may have a pronounced effect on the total amount secreted
by a flower. Although in some species nectar removal does not modify its production pattern
(Galetto and Bemardello, 1993, 1995; Galetto et al., 2000), in others the total amount of
sugar in the nectar may increase (Pyke, 1981; Galetto and Bemardello, 1995; Castellanos
et al., 2002) or decrease (Galetto and Bemardello, 1992; Bemardello et al., 1994;
Galetto et al., 1997). Predictions for these patterns are not straightforward because they
may be related to pollinators, environmental factors, plant resource allocation, or other factors
(Galetto and Bernardello, 2004).
Looking at the several characteristics of nectar production and dynamics, and also its interaction
with pollinator, several authors investigated the effect of nectar removal, the impact
over plant resources allocation (to nectar or seed production) and, at last, over cross pollination.
Ornelas and Lara (2009) suggested a possible theory to link cross pollination level,
nectar removal and increased yield. Studying different levels of nectar replenishment
and pollen receipt by the stigma, they suggested that pollination intensity and nectar
replenishment interact in their effects and affect seed production. Their study on Penste-
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