Responses of clonal river red gum (Eucalyptus camaldulensis) to waterlogging by fresh and salt water

Abstract

Summary. 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 glasshouse conditions for 16 weeks over winter. Both clones tolerated extended periods of waterlogging with fresh water without effects on growth, stomatal conductance or net gas exchange. Formation of adventitious roots in the soil surface under waterlogging with fresh water was earlier 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 than clone M66. In contrast, clone M66 may be more suited to saline conditions. Greater uptake of Na+ and Cl- occurred in clone M80. Lower water uptake of salt water and possibly greater tissue tolerance of salt by clone M66 may lead to greater survival under conditions where plants use saline groundwater. The results suggest that clone M80 would survive and utilise water when planted further upslope of highly salinised areas, with clone M66 better able to survive closer to such areas. The variation demonstrated between clones of E. camaldulensis indicates closer matching of their reclamation potential and the environmental conditions of damaged catchments should be possible.