RESPONSES OF CLONAL RIVER RED GUM (EUCALYPTUS-CAMALDULENSIS) TO WATERLOGGING BY FRESH AND SALT-WATER

Effects of waterlogging by fresh and salt water on growth, water use, stomatal conductance and net gas exchange of 2 clones (M80 and M66) of river red gum (Eucalyptus camaldulensis Dehnh.) were studied under gl asshouse conditions for 16 weeks over winter. Both clones tolerated ex tended periods of waterlogging with fresh water without effects on gro wth, stomatal conductance or net gas exchange. Formation of adventitio us roots in the soil surface under waterlogging with fresh water was e arlier in clone M80 than clone M66, as was recovery in water use. Thus , clone M80 may be more tolerant of soil saturation with fresh water t han clone M66. In contrast, clone M66 may be more suited to saline con ditions. Greater uptake of Na+ and Cl- occurred in clone M80. Lower wa ter uptake of salt water and possibly greater tissue tolerance of salt by clone M66 may lead to greater survival under conditions where plan ts use saline groundwater. The results suggest that clone M80 would su rvive and utilise water when planted further upslope of highly salinis ed areas, with clone M66 better able to survive closer to such areas. The variation demonstrated between clones of E. camaldulensis indicate s closer matching of their reclamation potential and the environmental conditions of damaged catchments should be possible.