Transpiration is another important character in crop physiology
correlated with A and gs. It is driven by differences in vapor pressure and is influenced by environmental factors. Year and cropping
system influenced considerably transpiration (Table 4). Transpiration (E) (mmol H2O m−2
s
−1
) was higher in the organic than in the
conventional system in 2010 and in 2011 (4.49 vs. 4.04 and 4.10
vs. 3.42) and, considering the average of 2 years data, it was 15.5%
higher. None of the cultivars showed any differences between the
two systems apart from Regent, which in 2010 had a higher value of
transpiration in the organic than in the conventional system. Sibari,
Alican and Wally Red had the highest transpiration values in the
conventional cropping system in 2010, while Augurio had the highest value of E in the conventional cropping system in 2011 (Table 4).
Net assimilation rate, intercellular carbon dioxide concentration
and transpiration are directly influenced by stomatal conductance.
The average stomatal conductance (gs) (mol H2O m−2
s
−1
) was
higher in the organic than in the conventional system in each year
of cultivation (0.64 vs. 0.59 and 0.61 vs. 0.49; Table 5)