Gravel et al. performed detailed studies of fruit composition
in response to different nutrients in four cultivars, and found that
fruit glucose levels correlated negatively with calcium, but magnesium
and sulphate positively affected fructose (Gravel et al., 2010).
Whether these changes will be discerned when the fruit is eaten
is not known, but it may be possible. Heeb et al. (2005) found that
organic sources of nitrogen and ammonium were superior to inorganic
nitrate in increasing fruit sugars and acids, which led to better
favorable ratings by taste-testing.