Functional copper requirement for catechol oxidase activity in plantation Eucalyptus species
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Copper (Cu) deficiency in eucalypts is associated with tree deformation and reduced wood production from plantations. Presently, diagnosis of the early stages of Cu deficiency is unreliable as critical tissue Cu concentrations for tree growth have not been defined. Since wood quality is usually impaired in advance of tree growth, a biochemical test for Cu deficiency was sought for three Eucalyptus species commonly used in plantation forestry (E. globulus Labill., E. grandis Hill ex Maiden and E. urophylla Blake). Foliar Cu requirements for catechol oxidase activity were determined in a glasshouse sand culture study with 10 rates of Cu supply (0, 10 -15, 10 -14, 10 -13, 10 -12, 10 -11, 10 -10, 10 -9, 10 -7 and 10 -5 M). In contrast to shoot dry weight, which only responded to Cu supply in E. urophylla, foliar Cu concentration and catechol oxidase activity, in 140-day-old seedlings, increased with the addition of Cu in all species. Stem lignification also responded to Cu supply in parallel to the activity of catechol oxidase. Functional Cu requirements of 2.4, 2.1 and 2.6 mg kg -1 dry weight for catechol oxidase activity in E. globulus, E. grandis and E. urophylla, respectively, were derived from statistical models fitted to the relationship between catechol oxidase activity and Cu concentrations in recently matured leaves.
|Publication Type:||Journal Article|
|Murdoch Affiliation:||School of Biological Sciences and Biotechnology|
|Publisher:||Kluwer Academic Publishers|
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