Root and Shoot Growth of Eucalyptus in Response to Container Configuration and Copper Carbonate

Abstract

After 7 months Modifying container design by changing the height : width ratio of containers or coating the interior surface of containers with copper compounds are among the various strategies used to prevent potbound root systems. Root growth was stimulated when plants with a naturally deep root system were grown in containers with a 7.9 height : width ratio, while growth of plants with a shallow root system was severely restricted in those containers (Biran and Eliassaf, 1980). The growth of deep-rooted woody plants also increased when these plants were grown in deeper containers with a height : width ratio of 3.0 vs. shallow containers with a height : width ratio of 0.4 (Keever et al., 1985). Copper compounds applied to the inside of containers or flats inhibits root growth, resulting in a more fibrous root system with a better root distribution within the container (Arnold and Struve, 1989). Studies on various species found increased and decreased growth responses for plants in copper-treated vs. nontreated containers (Arnold and Struve, 1989; Beeson and Newton, 1992; Furuta et al., 1972). Our objectives were to determine whether shoot and root growth of a vigorously growing species, Eucalyptus citriodora Hook., would be better in tall vs. regular-shaped containers with the same volume and whether coating the inside of the container with CuCO3 would reduce root circling and improve root and shoot growth. Eucalyptus citriodora liners were transplanted on 15 Aug. into plastic 3.7-liter containers of regular (standard no. 1) or tall configuration. Regular containers were 16.0 cm in diameter and 17.5 cm tall; the dimensions of the tall ones were 10.0 and 40.0 cm, respectively. The height : width ratio of regular and tall containers were 1.1 and 3.8, respectively. All containers were filled with 3.0 liters of Univ. of California Mix no. 2 (Baker, 1985). Tall containers were manufactured from polyvinyl chloride pipe cut to the specified height. Nylon screen was fastened to the bottom of the pipe and taped around the outside of the pipe.