Anatomical Aspects of Rooting Nabali and Raseei Olive Semi-Hardwood Stem Cuttings

This research was conducted to study the anatomy of adventitious root formation in semi-hardwood stem cuttings of ‘Nabali’ and ‘Raseei’ olive cultivars. Semi-hardwood stem cuttings of ‘Nabali’ and ‘Raseei’ olive cultivars were prepared and rooted in a greenhouse at various sampling dates. Stem segments from the basal portion of the cuttings were taken before rooting and at 2-week intervals during the rooting period to investigate anatomical structure and adventitious root formation on the cuttings. The results indicated that anatomical structure of the stem cutting cross sections for both olive cultivars was basically similar. Origin of root initials in ‘Nabali’ and ‘Raseei’ olive cuttings is the cambial zone. In both olive cultivars, sclerenchyma tissue was found to form a continuous ring of 3-6 layers of cells, and did not form a mechanical barrier for adventitious root formation. Noticeable increase in the thickness of the cortex during rooting was observed in ‘Nabali’ cuttings as compared to ‘Raseei’, which might act as a barrier for development of the root primordia. Difficulty in rooting ‘Nabali’ cuttings could be attributed to changes in anatomical structure of the cutting during the rooting period