Effects of nocturnal warming and water deficit on leaf carbon
gain and biomass productivity
There were no interactive effects of nocturnal warming and water
treatment on Asat in both temperature regimes (i.e. cool
and warm; Table 3); while significant main effects were observed for
nocturnal warming under cool temperature regime (P <0.01) and
for water treatment under warm temperature regime (P =0.02), but these
effects were generally small (Figure 1). Although both treatments had no
significant effects on Rn, the variation of
Asat-Rn within each temperature regime
was similar to that of Asat, with the main effect found
for temperature (P <0.01) and water treatment (P
<0.01) under cool and warm temperature regimes, respectively
(Figure 2).
Within the cool temperature regime, nocturnal warming did not affect
vegetative (P =0.17), fruit (P =0.36) or total biomass (P =0.69), while
all biomass variables were significantly reduced under water-limited
conditions compared with well-watered conditions (P <0.05 for
all variables; Figure 6, Table 3). Within the warm temperature regime,
significant interactive effects between nocturnal warming and water
treatment were observed for biomass production (P <0.001 for
all variables). Dry mass production was promoted by warm night
temperatures under well-watered conditions, but was reduced or unchanged
under water deficit stress.