Solar radiation and temperature have a large influence on fruit
sugar accumulation. Under normal growth conditions, however, it
is difficult to attribute the effect of each individually. Higher temperatures
(ranging from 26 to 30 ◦C) led to increased TSS when
applied during fruit cell division and ripening due to, respectively,
changes in carbohydrate biosynthetic enzyme activity (Walker and
Ho, 1977), and increased transpiration (Gautier et al., 2008). In both
instances, fruit fresh weight and days to harvest were also sometimes
reduced at the higher temperatures. Sink competition also
comes into play. Increasing temperature in a cherry tomato promoted
fruit evapotranspiration and higher sugar levels, but with
increased sink competition sugar content decreased, presumably
due to respiration at the higher temperature (Gautier et al., 2005).