Transpiration and respiration are two mechanisms of water loss in fresh agricultural
products, resulting in visual and texture degradation. Neglecting respiration as a
mechanism of water loss may lead to erroneous results at saturation where water vapour
pressure deficit is zero and thus water loss is expected to be zero, however, the existence
of a finite water loss is noted. In this context, an analysis of the associated with
transpiration and respiration water loss in figs (Ficus carica L.) was carried out at 0oC,
10oC and 20oC and 45.64%, 80.22% and 98.65% relative humidity as well as the air
conditions of walk-in cold storage rooms. The estimated transpiration rate ranged between
0.11-1.416 mg cm-2
h
-1
for a water vapour pressure deficit of 0.0-0.98 kPa. The water
vapour pressure deficit estimation was based on the difference between cold air
temperature and figs’ surface temperature. The respiration rate was calculated at 0oC,
10oC and 20oC as 0.47±0.08, 0.94±0.11 and 2.69±0.17 mLCO2100g-1
h
-1
. Quantification of
the water loss showed that at 20oC and saturation, the water loss due to respiration
accounts for 3.9% of the respective water loss due to water vapour pressure deficit while
on average, the water loss due to respiration accounts for 1.5%, 2.1% and 2.6% of the
water loss due to water vapour pressure deficit at 0oC, 10oC and 20oC.
Does transpiration control stomatal responses to water vapour pressure deficit?
