Effects of anatomical structures and phenolic compound deposition on the rooting of olive cuttings

Abstract

Olive tree is propagated vegetatively, which requires good adventitious rooting. The objective of this study was to analyze the influence of the presence of anatomical structures and of phenolic compound deposition on the rooting of stem cuttings of olive. Semihardwood cuttings from olive cultivars Maria da Fé, Santa Catalina, Ascolano 315 and Grappolo 541, treated with indole-3-butyric acid solution at a concentration of 3000 mg L−1, were studied. During the rooting period of the experiment, which totaled 60 days, the origin of the root primordia, the changes in the anatomical structures of the wounded region and the presence of phenolic compounds and lignin in this region were analyzed and at the end of 60 days the phytotechnical parameters such as rooting percentage and calloused cuttings were evaluated. Cuttings with a high percentage of callogenesis were less likely to root. Phenolic compounds were detected in cambial cells, confirming the accumulation of these compounds in the regeneration zone of the cuttings. The sclerenchyma ring, like the phloem and cortical tissue, was a structure that did not prevent the adventitious rooting of olive cuttings but represented a structural obstacle to the emission of adventitious roots. The presence of phenolic compounds in the cambial region raises the possibility that they influence adventitious rooting, since they have close relationships with enzymes involved in the metabolism and transport of auxin.