Response Of Four Ornamental Tree Species To Soil Cadmium And Lead Contamination

The reaction of the growth and physiological and biochemical of Acer mandshurica Max., Philadelphus schrenkii Rupr., Rosa davurica Pall. and Lonicera maackii Max. were studied under the stress of cadmium and lead in the soil by the seedlings in pots in greenhouse, the resistance of the four species seedlings to cadmium and lead was evaluated. Every species was designed under different concentration gradient, Cd~2+: 50, 100, 200 mg.kg~-1 (pure Cd~2+ ), Pb~2+: 500, 1000, 2000 mg.kg~-1 (pure Pb~2+ ), simultaneity CK was designed (show CK, Cd50, Cd100, Cd200, Pb500, Pb1000, Pb2000 ). The results were as follows:1 Under the stress of cadmium and lead contamination, leaves appeared chlorosis system, Cd~2+ treatment was the most obvious, the system of Acer mandshurica Max. and Lonicera maackii Max. were the most outstanding among the four tree species seedlings. The lower concentration of Cd~2+ and Pb~2+ can stimulate the growth of new branches and leaves of most tree species. Each index decreased with the Cd~2+ and Pb~2+ concentration enhanced, thereinto, the effect on Acer mandshurica Max. was maximal.2 Under the stress of cadmium and lead contamination, peroxidation of membrane lipid were affected, relative conductivity and manlondialdehyde (MDA) content were increased. With the increase of cadmium and lead treatment concentration, the variety range of relative conductivity and manlondialdehyde (MDA) content of Acer mandshurica Max. was highest. That was enhanced 59.84% and 44.44% than that of CK under the highest cadmium concentration treatment, that was enhanced 75.59% and 58.33%than that of CK under the highest lead concentration treatment,, followed by that of Lonicera maackii Max., that of Philadelphus schrenkii Rupr. and Rosa davurica Pall, were least.3 Under the stress of cadmium and lead contamination, the free radical scavenging system was seriously affected. The activity of superoxide dismutase(SOD) of four tree species seedlings decreased with the increasing of cadmium and lead treatment concentration, nevertheless, the activity of catalase(C AT) of four tree species seedlings was different because of different seedlings species. The variation range of Acer mandshurica Max. and Lonicera maackii Max. were higher than Philadelphus schrenkii Rupr. and Rosa davurica Pall.. The activity of CAT of four tree species seedlings was different variationa trend.4 Under the stress of cadmium and lead contamination, photosynthetic system weredamaged. Chlorophyll content, Fv/Fm, qP, OPS II and net photosynthetic rate were decreased, whereas the qNP was increased. General speaking from the variation of chlorophyll content, Fv/Fm, qP, Philadelphus schrenkii Rupr.> Lonicera maackii Max.> Acer mandshurica Max.; the resistance of four tree species seedlings to lead was Philadelphus schrenkii Rupr. >Rosa davurica Pall. > Lonicera maackii Max.> Acer mandshurica Max.