Physiological And Biochemical Mechanism Of Biochemical Substance Of Schima Superba On Degrading Aluminum Toxicity To Chinese Fir

Chinese fir, recommended as the most important timber tree species in sorthern China, it's continuous planting induced soil degradation. Its culture area covers 11,000 thousand hektare and calculation up 3.5 hundred million. Chinese fir continuous plantation obstacle and low economic efficiency of Chinese fir plantation ecosystem caused by long term pure plantation cultivation.In order to explore the soil degradation, the research had turned to " the nutrition stress", especially Al and Mn. The acid soil of the south was rich in Al which was the very for Al toxicity in the forest.This paper was concerned with using Schima superba to degrade the Al toxicity of Chinese fir. The leaves of Schima superba were extracted through supercritical fluid CO₂ extraction technology by orthogonal design. So the Chinese fir germination was used to explore the allelochemicals. The main chemical composition of the SFE extract was determined by High Performance Liquid Chromatography and Mass Spectrometry (HPGC/MS); the qualitative analysis was done by Infared Red Spectroscopy (IR) and Nuclear Magnetic Resonance (NMR). Seed germination was used to indetify the biochemicals by man-made the material. The regressive rotation and water cultivate experiment were utilized to predict the physiological and biochemical index of the treaments. The threshold of Al concentration and the threshold of the biochemical substance to degrade Al toxicity of the Chinese fir on various pH value were determined by establishing the models for the growth. The main results as follows:1. The biomasary was used to discuss the leaves allelochemicals under various conditions of supercritical fluid CO₂ extration of Schima superba leaf. The result showed that compared with the pure solution of allelochemicals, the Al-included solution of allelochemicals had promoted the Chinese fir germination at some extent. But compared with the pure Al solution control, different extract parameter had different effect on seed germination. It was because there were heterogeneity and various content in Schima superbaleaf which was extracted under different parameters. Some of the component had positive effect on Chinese fir germination, for example, the parameter 1, the extract of supercritical fluid one had promotion the radical length, plumular axis and fresh weight. But some of the component had negative influence on the germination, for example, the parameter 1 had inhibition effects on the absolute germination rate, absolute germination power and dry weight. The allelochemicals of the same extract parameter had different effect on the same identification index, for example, Al-included solution of extraction through supercritical fluid 2 had promotion on some germination index when in lOOmg/kg and 200mg/kg, but it turned to inhibition in 500mg/kg.2. The active fragments of allelochemicals on II and IV framers were identified by HPGC-MS, IR and NMR technology, the important autointoxicational allelochemicals which can complexed with Al in fragment 2 and 4 were: 2, 5-di-tetrabutyl-l-hydroxy-trimethylbenzene, Tetradecanoic acid, Hexadecen-1-ol, 1-phenylpropane, 4-methyl -4-hydroxy-pentanone, m-hydroxy phthalic acid, DL-hydroxy-l,2,3-proanetracarboxylic and so on. By the analysis to the resembling cofficient of all the substance, the DL-hydroxy-l,2,3-proanetracarboxylic which had the maximal resembling coefficient was discussed in the paper.3. The germination was used again. The result was that every Chinese fir germination index had different sensibility to the various concentration of DL-hydroxy-l,2,3-proanetracarboxylic. Compared with the distilled water contrast, different concentration of DL-hydroxy-l,2,3-proanetracarboxylic had inhibition effect on absolute germination rate, absolute germination power, fresh weight and dry weight of Chinese-fir seeds. When the concentration under 3.10mM, the DL-hydroxy-l,2,3-proanetracarboxylic behaved obvious promotion the radicle length and plumular axis.4. The design of the regressive rotation and water cultivate experiment were utilized to analyze the various of pH value, the concentration of Al, the concentration of nutrition and the concentration of DL-hydroxy-l,2,3-proanetracarboxylic, which influence the 1 year'chinese fir seedings on the physiological and biochemical indexs such as the activation of NR,the relative electrical conductivity.the activation of SOD.the net photosynthetic rateand the dark respiration rate, etc. Combined the analysis of variance to the index and the factors, the series of the quadratic equation of four factors were optimized and established.5. Based on the regressive equations, a series of curves were set up. The curves were about the physiological and biochemical indexs responsing on pH value, the concentration of DL-hydroxy-l,2,3-proanetracarboxylic, the concentration of Al and the concentration of nutrition.The different factors had different impact on the physiological and biochemical indexs. The results were showed in the curves:(1) . As the concentration of Al, DL-hydroxy-l,2,3-proanetracarboxylic and nutrition in the solution were to a certainty, and the activation of NR was increased with the pH value along with the Al stress. The activation of SOD was descended at some degree along with the pH value on collectivity. The relative electrical conductivity was turned to reduce slightly. And the net photosynthetic rate was augmented among which the pH value was increased, whereas the dark respiration.(2) . As the pH value, the concentration of nutrition in the solution and the concentration DL-hydroxy-l,2,3-proanetracarboxylic were to a certainty, and the activation of NR and SOD was descended obviously with the strength of Al along with the Al stress. The relative electrical conductivity was turned to increase remarkably with the Al stress pricked up. The net photosynthetic rate and the dark respiration were descended among with the concentration of Al was increased.(3) . As the pH value, the concentration of Al and nutrition in the solution were given, and the activation of NR was descended obviously with the concentration of DL-hydroxy-l,2,3-proanetracarboxylic along with the strength of Al stress. The relative electrical conductivity was turned to decline slightly with the time. And the net photosynthetic rate was accelerated with the increasing on the concentration of DL-hydroxy-l,2,3-proanetracarboxylic, vice verse the dark respiration. The concentration DL-hydroxy-l,2,3-proanetracarboxylic had very complex influence on the activation of the SOD. The activation of SOD was descended with the strength of DL-hydroxy-l,2,3-proanetracarboxylic at some degree during the first 30 days' stress. But the concentration of matter had little impression on the activation of SOD in the last 15 days...