Influence of cadmium on photosynthesis and chlorophyll fluorescence characteristics in Acer ginnala and Acer mono.

Using pot experiment,the impact of soil Cd on photosynthesis and chlorophyll fluorescence characters of biennial northern broadleaved tree were investigated.Using the cultivation medium of the soil and weathering sand,designs 4 kinds of Cd concentration(comparison,10,50,100,200 mg·kg-1),simultaneously designing comparison(only sprinkling tap water) which aims to analyze the inner mechanism of Cd pollution and provides basis data for street trees choice of northern cities and scientific application.The result shows that Cd10 stimulates the increasing of Pn,Gs and Tr of Acer ginnala,gradually reducing with the Cd concentration rise,Ci is lower than comparison in Cd10,gradually increasing afterwards;Pn of Acer mono decreases,Ci increases,Gs and Tr firstly rise and drop afterwards.Thus it may be known that the non-stomatal limitation causes decreasing of Pn processed by high concentration Cd.Fv/Fm,Fv/F0,qP and qN of A.ginnala firstly rise and drop afterwards.With the increasing of Cd concentration,ΦPSⅡ reduces continually;the tendency of Fv/Fm,Fv/F0,qN and ΦPSⅠ in A.mono is the same to A.ginnala.The qP decreases with the increasing of Cd concentration.It seems that Cd has an effect on the growth of the two tree by destroying or restraining the success of photosynthesis.All index changes(besides Ci) of A.ginnala are bigger than A.mono for rise scope,but drop scope of A.mono is bigger than that of A.ginnala.Furthermore the patience of A.mono is better than that of A.ginnala.It provides theory evidence for application of Cd pollution in soil for the city.