OLIVE ROOT GROWTH OBSERVED BY FIELD RHIZOTRON
The olive (Olea europaea L.) is characterized by high drought tolerance and its roots show high transmigration capability and adaptability to changing conditions. Root growth is affected by the environment as is the functional specialization of each root structure. A quantity based analysis gives just a partial notion of the complexity of the process which allows the olive to be so adaptable. An experiment using rhizotrones was carried out that allowed sequential root growth, distribution, differentiation and mortality to be directly observed. Four olive trees were selected and a glass window for each tree (0.8 m deep by 1.3 m wide) was placed underground, 0.5 m away from the trunk in September 2007. Bi-weekly observations throughout the growing season made it possible to identify root growing rate and morphological changes. Based on their morphology roots observed have been divided into two different clusters <0.2 mm very fine (VF) roots, and >0.2 mm fine (F) roots. At no point during the observation period (from September 2007 to September 2008) did root growth stop, including winter months. The two clusters of roots behaved in a different way during the season. VF root growth peaked in February and F root growth from April to May. In both cases root growth drastically weakened from June to August with a faster reduction of VF roots. Root mortality was very low during the winter accelerating in May, likely influenced by an increase in temperatures. Root mortality slowed down deeper in the soil where moisture and temperature changes were not as high. All the presented results seem to be applicable to modern oliviculture, in high density orchard management, to obtain better control of the development of the whole plant and to reduce costs.
Polverigiani, S., Lodolini , E.M. and Neri, D. (2012). OLIVE ROOT GROWTH OBSERVED BY FIELD RHIZOTRON. Acta Hortic. 949, 271-278
root plasticity, root mortality, root turnover, soil moisture