Development of leaf water deficits in detached green and lime-chlorotic leaves of seedlings from populations ofEucalyptus obliqua L'Hérit

Abstract

The water relations of three populations ofEucalyptus obliqua affected by limechlorosis were studied by monitoring water loss of leaves detached from seedlings. Water was lost faster from chlorotic leaves than from green leaves of the same population; the rate of water loss was inversely propotional to the chlorophyll content. Although chlorophyll content may affect stomatal behaviour, the water loss curves were interpreted as indicating that cuticular aspects of leaf water retention were severely affected. These findings concur with recent observations of severe water stress in chlorotic plants growing on calcareous soils in the Cape Otway region. Moreover, it appears that the greater susceptibility of the acidic population to lime-chlorosis compared with that of the calcareous population would be a considerable disadvantage when growing on a calcareous site subjected to periodic droughts.