Zinc nutrition and leaf carbonic anhydrase activity ofEucalyptus maculata seedlings andTrifolium subterraneum

Abstract

Carbonic anhydrase activity in selected leaves was examined in relation to zinc supply to Eucalyptus maculata seedlings find Trifolium subterraneum grown in the glasshouse on a zinc-deficient sand.In both species, carbonic anhydrase activity was closely related to the zinc supply and fell to 0 in severely-deficient plants. Enzyme activity increased linearly as a function of the leaf zinc concentration. In E. maculata plants supplied with adequate zinc, carbonic anhydrase levels were only 3% of those in T. subterraneum.It is concluded that foliar zinc analysis is more sensitive than the carbonic anhydrase assay for determining the zinc status of E. maculata seedlings. Critical zinc concentration for young fully-expanded E. maculata leaves was between 9 and 10 #g g-~ dry matter.

Phosphite and nutrient applications as explorative tools to identify possible factors associated with Eucalyptus gomphocephala decline in South-Western Australia

“…Furthermore, Zn deficiency is readily induced in eucalypt seedlings when fertiliser lacking Zn is applied (Wallace et al 1986;Dell and Wilson 1989). Thus, it is possible that use of fertiliser in agricultural pursuits adjacent to the E. gomphocephala trees may contribute to nutrient stress in mature E. gomphocephala trees.…”