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.