Table 1 Leaf temperature (T_leaf), photosynthetic efficiency (Fv/Fm), stem and minimum water potential (ψ_stem and ψ_min) measured in 5C and Riesling x 5C (RR) plants 8 weeks after the beginning of treatments (n = 5–8). W = well-watered plants; D = drought-stressed; C = control, non-phylloxerated; P = root phylloxerated. * indicates statistically significant differences within the factors (Irrigation or Infestation). A significant interaction between factors (Irr x Inf) was observed in Fv/Fm measured in RR, i.e. within W level: C > P; within P level: W < D

W

D

C

P

Irr x Inf

W

D

C

P

Irr x Inf

Tleaf, °C

32.6 ± 0.5

33.5 ± 0.6

32.8 ± 0.5

33.3 ± 0.6

n.s.

31.6 ± 0.6

33.5 ± 0.7*

32.1 ± 0.6

33.0 ± 0.7

n.s.

Fv/Fm

0.80 ± 0.01

0.81 ± 0.01

0.80 ± 0.01

0.81 ± 0.01

n.s.

0.78 ± 0.01

0.79 ± 0.01

0.79 ± 0.01

0.77 ± 0.01

*

ψ_stem, −MPa

0.64 ± 0.03

1.08 ± 0.03*

0.85 ± 0.03

0.87 ± 0.03

n.s.

0.54 ± 0.04

0.89 ± 0.04*

0.72 ± 0.04

0.71 ± 0.04

n.s.

ψ_min, −MPa

1.00 ± 0.04

1.29 ± 0.04*

1.08 ± 0.04

1.20 ± 0.04*

n.s.

0.82 ± 0.04

1.10 ± 0.05*

0.97 ± 0.04

0.95 ± 0.05

n.s.