Nardini Andrea, Gascó Antonio, Raimondo Fabio, Gortan Emmanuelle, Lo Gullo Maria A, Caruso Tiziano, Salleo Sebastiano
Dipartimento di Biologia, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italia.
Tree Physiol. 2006 Sep;26(9):1137-44. doi: 10.1093/treephys/26.9.1137.
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 (A(L)) was closely and positively related to root hydraulic conductance so that whole-plant hydraulic conductance scaled by A(L) 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.
我们研究了自根苗或嫁接到具有不同大小控制潜力砧木上的幼龄橄榄树的水力结构。对诱导接穗旺盛生长（莱基诺‘密涅瓦’，LM）或接穗矮化（莱基诺‘矮化’，LD）的油橄榄（Olea europea L.）cv‘莱基诺’无性系进行了不同接穗/砧木组合（LD、LM、LD/LD、LM/LM、LD/LM和LM/LD）的研究。在LD根系上生长的枝条比在LM根系上生长的枝条叶表面积少约50%。根系占植物水力阻力（R）的60 - 70%，而嫁接处的水力阻力可忽略不计。LD根系的水力导度（K = 1/R）比LM根系低达2.5倍。总叶表面积（A(L)）与根系水力导度密切正相关，因此按A(L)缩放的全株水力导度在各实验组之间没有差异。相应地，最大蒸腾速率和最小叶水势在各实验组之间没有显著差异。我们得出结论，根系水力导度降低可能解释了砧木诱导的橄榄矮化现象。
