Study On The Ability Of Resistance To Heavy Metal And Acid Rain Stress Of 3 Main Landscape Trees In Fuzhou

The reaction of the growth and physiological and biochemical of Ficus microcarpa L.f., Cinnamomum camphora(L.)Presl,and Mangifera indica Linn were studied under the stress of copper and zinc in the soil and simulated acid rain by the seedlings in pots.Every species was designed under different concentration gradient,Cu²⁺:50,100,200,400 mg·kg^-1(pure Cu²⁺), Zn²⁺:50,125,250,500mg·kg^-1(pure Zn²⁺),simulated acid rain:pH5.0,pH4.0,pH3.0, pH2.0.The control group(CK)was set as well.The experiment was sustained for about 6 months.The results were as follows:1.Under the stress of copper,zinc contamination,the leaf cell permeability of three species seedlings were increased,Zn²⁺treatment was the most obvious,Mangifera indica Linn was the most outstanding among the three garden species seedlings,but the leaf cell permeability may decreased with low concentration,maybe is the lower concentration of Cu²⁺,Zn²⁺can stimulate the growth of them;but under the stress of copper contaminaton,the effect on Ficus microcarpa L.f.was maximal,under the concentration of 400 mg·kg^-1Ficus microcarpa L.f.had very significant differences from the contrast;under the stress of simulated acid rain,the leaf cell permeability of three species had a tendency to increase,except for Cinnamomum camphora(L.) Presl under the concentration of pH5.0,Mangifera indica Linn increased most fastest between three species.2.Under the stress of copper,zinc contamination,the photosynthetic system of 3 species were damaged.The chlorophyll contents and net photosynthetic rate of species seedlings increased first and decreased afterwards,the variation range of three garden species seedlings was different because of different species.The decreased range of Ficus microcarpa L.f.was higher than other two species under the stress of copper and zinc contamination,the Cinnamomum camphora(L.)Presl was minimum.Under the stress of simulated acid rain, the effect of photosynthetic on Mangifera indica Linn was maximal,under the concentration of pH2.0 Mangifera indica Linn had significant differences from the contrast,Cinnamomum camphora(L.)Presl was minimum,the lower concentration of acid rain can stimulated the chlorophyll contents and net photosynthetic rate of the species while higher concentration it decreased.3.Under the stress of copper,zinc contamination,the free radical scavenging system was seriously affected.The activity of peroxidase(POD)and the activity of catalase(CAT)were increase or decrease with the increasing concentration of two heavy metals.The variation range of three garden species seedlings was different because of different heavy metals and different species.The activity of POD and CAT of 3 species had different tendencies,the effect of protective enzyme system on Ficus microcarpa L.f.was maximal under the stress of copper contamination;Mangifera indica Linn was maximal under the stress of zinc contamination. Under the stress of simulated acid rain,the free radical scavenging system had a tendency to increase first and decreased afterwards,and it also had a tendency to decreased just like Mangifera indica Linn,it showed that the effect of protective enzyme system on Mangifera indica Linn was maximal.4.Under the stress of copper,zinc contamination,the growth of three species seedlings can also be affected.The species under stress can be thiner on basal diameter and lower on high,the less on biomass accumulation,Zn²⁺treatment was the most obvious.The lower concentration of Cu²⁺,Zn²⁺can stimulate the growth of new branches and leaves of three garden species,but as the concentration is higher,the index decreased,thereinto,the effect on Mangifera indica Linn was maximal under the stress of zinc contamination,Ficus microcarpa L.f.was maximal under the stress of copper contamination.Under the stress of simulated acid rain,three species seedlings had different growth appearances,the variation range was different because of different species, the lower concentration of acid rain can stimulated the growth of the three species while higher concentration it inhibited the growth of the three species.Through overall evaluation by subordinate function method,the results had shown that the resistance of three garden species to copper stress could be ordered as:Cinnamomum camphora (L.)Presl＞Mangifera indica Linn＞Ficus microcarpa L.f..The results had shown that the resistance of three garden species to zinc stress could be ordered as:Ficus microcarpa L.f.＞Cinnamomum camphora(L.)Presl＞Mangifera indica Linn.The results had shown that the resistance of three garden species to simulated acid rain stress could be ordered as:Cinnamomum camphora(L.)Presl＞Ficus microcarpa L.f.＞Mangifera indica Linn.