© 2006 Heron Publishing—Victoria, Canada
Is rootstock-induced dwarfing in olive an effect of reduced plant hydraulic efficiency?
Andrea Nardini (1, 4), Antonio Gascó (1), Fabio Raimondo (2), Emmanuelle Gortan (1), Maria A. Lo Gullo (2), Tiziano Caruso (3) and Sebastiano Salleo (1)
1. Dipartimento di Biologia, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italia / 2. Dipartimento di Scienze Botaniche, Università di Messina, Salita Sperone 31, 98166 Messina S. Agata, Italia / 3. Dipartimento di Colture Arboree, Università di Palermo, Viale delle Scienze 11, 90128 Palermo, Italia / 4. Corresponding author (nardini@units.it) / Received October 12, 2005; accepted December 4, 2005; published online June 1, 2006
Summary
We investigated the hydraulic architecture of young olive trees either self-rooted or grafted on rootstocks with contrasting
size-controlling potential. Clones of Olea europea L. (Olive) cv ‘Leccino’ inducing vigorous scion growth (Leccino ‘Minerva’, LM) or scion dwarfing (Leccino ‘Dwarf’, LD) were
studied in different scion/rootstock combinations (LD, LM, LD/LD, LM/LM, LD/LM and LM/LD). Shoots growing on LD root systems
developed about 50% less leaf surface area than shoots growing on LM root systems. Root systems accounted for 60–70% of plant
hydraulic resistance (R), whereas hydraulic resistance of the graft union was negligible. Hydraulic conductance (K = 1/R) of LD root systems was up to 2.5 times less than that of LM root systems. Total leaf surface area (AL) was closely and positively related to root hydraulic conductance so that whole-plant hydraulic conductance scaled by AL did not differ between experimental groups. Accordingly, maximum transpiration rate and minimum leaf water potential did
not differ significantly among experimental groups. We conclude that reduced root hydraulic conductance may explain rootstock-induced
dwarfing in olive.
Keywords:
grafting, HPFM, Leccino, Olea europea, root hydraulics, transpiration rate, water potential.
