| Acid rain pollution is one of the major environmental problems over the world. Exploring the resistance of garden plants to acid rain pollution and enhancing plant resistance by exogenous regulating, with a certain reference value for prevention of landscape vegetation selection and acid rain pollution.In this study, one year old A. zerumbet chosen to be tested material.According to the Sichuan local natural characteristics of acid precipitation,with different pH values (2,2.5,3,3.5,4,4.5,5.6) of simulated acid rain treatment on test materials,and different concentrations of lanthanum solution spraied before pH3.0acid rain spraied on materials.This test is in order to know the response of A. zerumbet physiological and ecological indexes of different pH acid rain, and lanthanum on resistance to the effects of acid rain stress. The main results are as follows.1) pH≤3.5simulated acid rain caused significant harm on leaves, formation of white to reddish brown round blobs. The test material under pH4.0simulated acid rain, few leaves appeared granular faded and little burn marks after30d.2) High concentrations (pH≤2.5) Simulated acid rain, inhibited the A. zerumbet height growth, while the pH3.5-pH4.5simulated acid rain could promote the A. zerumbe height growth.3) pH≤3simulated acid rain leaded to a reduction in A. Zerumbet chlorophyll content. pH5.6of simulated acid rain on the chlorophyll content almost had no effect.Car content increased with the pH increased first and then decreased, the peak was pH3.0and pH3.5.4) With the increase of simulated acid rain treat times, soluble protein accumulation was blocked. But pH3.0treatment on soluble protein accumulation had a certain role in promoting. Soluble sugars in the pH≥3.0treatments might have a higher level, and then decreased, in pH≤4.5treatment were first increased and later decreased.5)MDA and EC increased with the pH value increases. But with the number of acid rain spray increase, MDA decreased and gradually stabilized, but EC increased.The content of Pro increased with the pH value increases., but with the in the number of acid rain spray increase, Pro content were gradually reduced, and tends to be stable.With the acid rain spray time increase, the activity of the SOD activity and POD activity decreased gradually.6) La3+concentration can relief acid rain stress, the most direct proof is to enable the material of pH3.0treatment without foliar injury symptoms, and promoted the plant height growth. Suitable La3+concentration(0.2-1.6mmol/L) also increased chlorophyll content, Pro content, POD and SOD activity, make Chla/Chlb, Car change more smoothly, decreased EC and MDA content, and lanthanum related to pH3.0acid rain stress as antagonistic effect on the organic matter accumulation8) In consideration of all index general, the author thinks of simulated acid rain on A. zerumbet damage threshold is pH3.5, La3+on pH3.0simulated acid rain to produce the best concentration of remission is0.4mmol/L. |
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