Abstract: Salix matsudana was grown in hydroponic culture for 14 d with CdCl₂ (0, 5, 25, 50 μmol·L^-1), the effects of Cd on photosynthetic performance and endopetidase activites of S. matsudana were investigated through analyzing chlorophyll, Rubisco, PEPC free amino acid and endopetidase. Total chlorophyll, chlorophyll a and b were decreased in Cd-treated plant, Rubisco activity was reduced with Cd levels in the medium, PEPC activity in roots and leaves showed an decline under Cd treatment，free amino acids in roots remained no significant change, but free amino acids in leaves were increased depending upon concentration of Cd; endopeptidase in roots was hindered at different dose of Cd, however, endopetidase in leaves increased at higher dose of Cd compared to control. The results showed that the effects of Cd on photosynthesis of S. matsudana were related to decrease in photosynthetic pigments, up-regulation of endopeptidase in leaves and inhibition of CO₂ carboxylation.

Key words: Salix matsudana Koidz., Cd, photosynthesis, free amino acid, endopeptidase