MORPHOLOGICAL AND PHYSIOLOGICAL COMPARISONS OF CLONAL LINES OF EUCALYPTUS-CAMALDULENSIS .1. RESPONSES TO DROUGHT AND WATERLOGGING

Morphological and physiological responses to drought and waterlogging of six clonal lines of Eucalyptus camaldulensis Dehnh., originally fro m five geographically separated locations, were compared under control led glasshouse conditions. The clones differed significantly in their ability to produce leaf and root tissue during stress periods. Clones which produced the greatest numbers of leaves (Dongara, WA clone M76 a nd Silverton, NSW clone M79) had leaves of low specific weight, while clones which produced fewer leaves (Erudina, SA clone M66 and Murray B ridge, SA clone M86) had leaves of relatively high specific weight. Cl onal lines that produced the greatest leaf area also produced the grea test root weight. Comparisons of water use produced fewer differences, although clone M76, which produced the greatest number of leaves and the greatest total leaf area, also used the most water in both the dro ught and waterlogging trials. Stomatal conductance, net gas exchange a nd leaf nutrient allocation did not differ greatly among the clonal li nes. An ability to produce and maintain transpiration surface appears the most valuable physiological attribute of plants selected to dewate r damaged agricultural catchments currently being subjected to increas ing periods of waterlogging due to excessive clearing of native woodla nds.