Effects Of Acid Aluminum Composite Stress On The Physiological Indicators And Absorption Of Nutrients In The Chinese Fir Seedling

With the rapid development of modern industry, the phenomenon of acid rain pollutionbecomes worse and worse. Many research results show that the continuous planting ofcunninghamia lanceolata also can lead to soil acidification. The essence of soil acidification is Altoxicity, which is considered a main limit factor affecting plant growth in acidic soils. Southernsoil is acidic soil of rich iron-aluminized, and the soil pH reduction caused by acid rain pollutionand the continuous planting of cunninghamia lanceolata will inevitably lead to aluminum toxicityin Chinese fir. Based on this background, with the1year of Chinese fir seedlings as experimentalmaterial, we adopted soil culture experiment and investigated the effects of acid aluminumcomposite stress on the MDA content, activity of SOD, POD, CAT, PPO and chlorophyllfluorescence parameters in Chinese fir seedling leaf, and further analyzed the influence of acidaluminum composite stress on Chinese fir seedling Ca, Mg, Mn, Cu and P mineral nutrientaccumulation. And from the perspective of physiological metabolism and nutrient accumulation,we state the response mechanisms of the fir to acid aluminum composite stress theoretically. Theresults not only enrich the research content of cunninghamia lanceolata Al toxicity, but also lay acertain theoretical basis for prevention and control of Al toxicity as well as sustainablemanagement on Chinese fir. The main results are as follows.1. Under the acid aluminum composite stress, with the extension of stress time, the MDAcontent of Chinese fir seedling leaf showed a trend of rising. Under the condition of the sameacidity, with the increase of Al concentration in Chinese fir seedling, the MDA content showed atrend of rising, the MDA content of the plant was ck <low aluminum <middle aluminum <highaluminum. Under the condition of the same aluminium concentration stress, with the pH reductionof the potting soil, MDA content in plant leaf is on the rise. The MDA content of the plant isck<pH5.0<pH4.5<pH4.0.2. Under the same concentration of aluminum, POD activity of Chinese fir seedling wasincreased with pH decreased. At the same level of the acid treatment, with the increase ofconcentration of aluminum Chinese fir seedling POD activity showed the trend of first increased after decreased; With stress time deferred, the Chinese fir seedling leaf POD activity presented thefirst after rising downward trend.3. Under the same concentration of aluminum processing level, as the acid stress intensified,SOD activity increased, and under the condition of no aluminum, acid effects of SOD activity onChinese fir seedlings is largest. At the same level of the acid treatment, with the increase ofconcentration of aluminum in cunninghamia lanceolata seedlings, SOD activity reduced afterrising first. In pH5.0processing level, the aluminum concentration effects of SOD activity onChinese fir seedlings is largest. With the extension of stress time, the Chinese fir seedling leafSOD activity also presented the first after descending trend.4. With the stress time deferred, the CAT activity of Chinese fir seedling leaf showed a risingtrend. Under the same concentration of aluminum level, CAT activity of Chinese fir seedlingincreased as the acid stress intensified. And under the condition of high aluminum, the impact ofacid stress CAT activity on Chinese fir seedlings is the least. In pH5.0processing level, the CATactivity of Chinese fir seedlings showed first decreased after increasing trend with the increase ofAl concentration; under other level of the acid treatment, CAT activity of Chinese fir seedlingincreased with the increased concentration of aluminum5. Under the same acid treatment, the PPO activity increased with the increase of aluminumconcentration, and the influence of aluminum concentration on PPO activity of Chinese firseedling reduced with the reduction of the pH. At the same level of acid treatment, PPO activity ofChinese fir seedling increased with the increased of aluminum concentration, and under thecondition of no acid, the aluminum’s influence on Chinese fir seedling PPO activity is greater thanother acid treatment6. With the time of acid-aluminum composite stress increased, chlorophyll fluorescenceparameter of F0in Chinese fir seedling leaf showed an ascendant trend, whereas Fm, Fv showed adownward trend. Under the same level of acid treatment, chlorophyll fluorescence parameters ofF0showed as ck> low aluminum> middle aluminum> high aluminum; Fm, Fv of chlorophyllfluorescence parameters showed as ck<low aluminum <middle aluminum<high aluminum. Underthe same level of aluminum concentration, chlorophyll fluorescence parameters of F0showedck>pH5.0>pH4.5>pH4.0, while the Fm and Fv showed as ck<pH5.0<pH4.5<pH4.0. 7. Acid-aluminum composite stress inhibited the absorption of Ca, Mg, Mn and P in Chinesefir seedling, and the influence degree was different. Under the same level of acid treatment,content of Ca, Mg, Mn and P in Chinese fir seedling all showed ck> low aluminum> middlealuminum> high aluminum; Under the same level of aluminum concentration treatment, Ca, Mg,Mn and P content of root, stem and leaf of Chinese fir seedling all showedck>pH5.0>pH4.5>pH4.0. However, the change pattern of Cu content in root, stem and leaf afteracid-aluminum composite stress is not obvious in Chinese fir seedling.