Effects Of Combined Aluminum, Manganese, Calcium On Chlorophyll Content, Fluorescence And Absorption Of Nutrients Of Chinese-fir Seedings

With the increase of the world's population and development of industry, the phenomenon of global soil acidification turn more and more serious. Global forest decline caused by soil acidification had affected the human survival and development. Followed the increasing acidification of soil, manganese and aluminum become more easily dissolved, and manganese toxicity and aluminum toxicity had become one of the main factors that hazards plant growth. High content of iron and aluminum in acidic soil of southern China have laid a congenital condition for aluminum toxicity to plants.As the native tree species in southern China, Chinese-fir is one of the most important timber tree species in southern China. With the growing bursaphelenchus xylophilus damage of Pine massoniana forest, Chinese-fir plays an increasingly important role in protecting our physical security and ecological security. However the long-standing practice of forestry show that with the repeat planting ,Chinese-fir plantation has a lower stand quality and an obvious decline in forest productivity. Many research results revealed that the main reasons caused the decline productivity has a close relationship with biological characteristics of Chinese-fir, toxicity of their own and aluminum toxicity. In view of these reasons, This paper take the aluminum toxicity as the major research area, Chinese-fir as the research object and by hydroponic culture to carried out experimental research. By measuring the change of Chlorophyll content, Chlorophyll fluorescence characteristics and nutrient uptake of Chinese-fir seedings under different stress time, in combined of aluminum, manganese, calcium. To elaborate the mechanism of toxicity. The main results are as follows:(1) Under different stress time, the combined of aluminum, manganese, calcium,had different effects on the content of Chlorophyll a, Chlorophyll b and Chlorophyll (a+b).On the whole, most treatments had increased in a varily degrees, but the promotion was different. For the Chlorophyll a, the treatment 8 after the 7 days stress, the treatment 4 after the14 days stress and the treatment 15 after the 21days stress, had a maximum effect. Compared with the initial value, the improvement was 56.48%, 68.14%, 63.27%, respectively. For Chlorophyll b, the treatment 6 after the 7 days stress, the treatment 13 after the14 days stress and the treatment 13 after the 21days stress, have a maximum effect; Compared with the initial value, the improvement is 51.42%, 73.44%, 112.28%, respectively. As far as chlorophyll (a+b) was concerned, the treatment 8 after the 7 days stress, the treatment 13 after the14 days stress and the treatment 15 after the 21days stress, have a maximum effect; Compared with the initial value,the improvement is 52.20%, 67.48%, 84.38%, respectively。Under the same treatment in different stress time Chlorophyll a, Chlorophyll b and chlorophyll (a+b) had a different change trend. The range analysis results showed that, manganese ions took an maximum effect, next was aluminum ions.(2) Under different stress time, the combined of aluminum, manganese, calcium, had different effects on the Chlorophyll fluorescence of Chinese-fir seedlings after the 7 days, 14 days, 21 days stress time, Fm/F0,Fv/Fm had a maximum magnitude drop under the treatment 14(Al 0.5mmol,Mn 0.3mmol,Ca 0mmol), 7(Al 1mmol,Mn 0.5mmol,Ca 0mmol), 13(Al 0mmol,Mn 0.5mmol,Ca 0.5mmol). Manganese ions took an maximum effect on Fm/F0 and Fv/Fm..With the increasing concentration of manganese ions, the parameters of ChloropHyll fluorescence decline. And the maximum pHotochemical efficiency Fv / Fm and the electron transfer through PSⅡ(Fm/F0) were inhibited.(3)The nutrient content in different organs of Chinese-fir seedings had a greatly change. Different organs in different stress time, nutrient content in roots and nutrient content in leaves change greatly, but a lesser extent changes in stem. Under different treatments macroelement K,Ca, Mg and trace elements Al,Mn had a great change;but trace element Zn, Fe, Cu had a smaller change. Under different treatments, the content of Al in the roots changed evidently. But the content of K, Ca, Mg, Mn elements changed evidently in the leaves. This showed that under the combined action of aluminum, manganese, calcium, Al is malinly fixed in the roots of Chinese-fir seedlings. The changes of K, Ca, Mg, Mn in the leaves of the Chinese-fir seedlings impact the photosynthetic content to some extent.Thereby, affected photosynthesis and reduce the capacity of nutrient absorption and transformation of Chinese-fir.In summary, when pH = 4.5,under the solution culture, the combined aluminum, manganese, calcium has a significant impact on hlorophyll content, Chlorophyll fluorescence, and the content of K, Ca, Mg, Al, Fe, Cu, Zn, Mn nutrients on Chinese-fir seedlings.