Nutrient partitioning among the roots, hedge and cuttings of Corymbia citriodora stock plants

Many eucalypt species are difficult to propagate as rooted cuttings. The mineral nutrition of cuttings is a key factor that limits adventitious root induction but little is known about partitioning of nutrients by eucalypt stock plants. This study determined N, P, K, Ca, B, S, Mg, Mn, Zn, Al, Fe and Na concentrations in the root system, pruned hedge and harvested cuttings of stock plants of the eucalypt, Corymbia citriodora. Between 17% and 31% of total plant mass was collected as cuttings at each harvest. The mobile nutrients, N, K and S, were highly concentrated in the cuttings and were removed in high amounts (e.g. 27-46% of total plant N) at each harvest, whereas less-mobile nutrients such as Ca and Zn were less concentrated in the cuttings than other plant parts. Adventitious rooting of eucalypt cuttings has been related to B concentration but this study revealed that B was much more highly concentrated in the hedge than the cuttings. Management of N and K concentrations for shoot production, and B concentrations for adventitious rooting, may be critical for sustaining rooted cutting production by C. citriodora.