WPT under water deficit and growth chamber conditions
Given that both L3 and L13 have demonstrated great differences on water
consumption in the days after water withdrawal compared to WT plants, we
next subjected a new set of plants to water deficit (WD) under growth
chamber conditions (24.5 °C, humidity 55.5% and 100 µmol photons
m-2 s-1 on average). As previously,
before the suspension of irrigation, the transgenic lines transpired
slightly less than WT plants, with significant difference observed in
L13 at the second day of the experiment (Figures 5A,B). However, under
WD condition, WT transpiration dropped whilst transgenic lines
transpired more (up to 37% in L13) than WT at the day 5, which
corresponds to two days after water withdrawn (Figures 5A,B). From day 5
to 8, WPT decreased in all genotypes, but L13 kept transpiring more than
WT until day 8 (Figure 5B). Considering the total WPT throughout this
experiment, L3 and L13 transpired 19 g H2O
plant-1 (5.4%) and 57 g H2O
plant-1 (16.3%) more than WT, respectively (Figure
5C). Comparing the accumulated WPT of WT and the transgenic lines under
WW and WD periods separately, L3 and L13 transpired 7.8 and 15.5% less
than WT under WW, respectively, but with no statistical significance. By
contrast, L3 and L13 transpired 11.1 and 36.74% more than WT under WD
condition, respectively, but only L13 was statistically different from
WT (Figure 5C inset).