characterise saline-sensitivity of Populus x canescens, micropropagated
young trees were exposed to 25 mM and 100 mM in hydroponic culture. After exposure to saline
conditions the relative growth rate and biomass production was initially stimulated but
declined below growth of controls after several days. After three weeks of exposure to 100 mM
NaCl, leaves displayed severe injury indicated by chlorophyll loss and significant electrolyte
leakage as compared with controls or plants grown in 25 mM NaCl. Roots of poplar grown in
the presence of 100 mM NaCl contained elevated concentrations of malondialdyde indicating
that high salinity caused lipid peroxidation. Superoxide dismutase and catalase activities in
roots were enhanced immediately after exposure to saline conditions. With increasing exposure
time superoxide dismutase displayed a further increase, which was not accompanied by corresponding
increases in catalase activities, thus, suggesting that oxidative degradation of membranes
was caused by an imbalance of protective systems after long-term NaCl exposure.