Table 1.

Most common vessel length L₀ (m), maximum vessel length L_m (m), number of vessels per cross-sectional area of root xylem (N_V, no. mm⁻²), xylem vessel lumen diameter (d_L, mm), number of first order roots (N_R, no. trunk⁻¹), mean cross-sectional area of framework roots emerging from the trunk (A_CR, cm² root), and mean roostock trunk diameter (T_d, mm) for plants of Vitis vinifera cv. Merlot grafted onto V. riparia×V. rupestris cv. 101-14Mgt or V. Berlandieri×V.rupestris cv. 1103P root systems Each value is the mean from five plants for xylem measurements and rootstock trunk diameter and nine plants for root morphology measurements within the same rootstock and sampling date ± the corresponding standard error. Statistically significant differences between rootstocks are indicated by values within the same row that do not share the same lowercase letter (P ≤0.05).

Rootstock property	Root system
	V. riparia×V. rupestris cv. 101-14Mgt	V. berlandieri×V. rupestris cv. 1103P
L0 (m)	0.09±0.01 b	0.13±0.01 a
Lm (m)	0.52±0.06 b	0.70±0.04 a
NV (number mm−2)	27.92±3.60 a	27.33±3.27 a
dL (mm)	0.09±0.01 a	0.11±0.02 a
NR (number trunk−1)	15.00±1.26 b	22.44±2.47 a
ACR (cm2 root−1)	1.80±0.26 a	1.86±0.22 a
Td (mm)	42.53±0.91 b	65.19±0.86 a