Study On Physiological And Ecological Adaption Of Typical Plants In Pyrite Zone Of Dafang, Guizhou

In order to understand physio-ecological mechanisms of two kinds of typical plants, Symplocos tetragona Chen et Y.F.Wu and Betula luminifera H. Winkl. adapting for sulfur and iron in different pyrite zone in Dafang county, Bijie city, Guizhou province, their photo-physiological parameters, such as net photosynthetic rate(Pn), transpiration rate(Tr), stomatal conductance(Gs) and water utilization efficiency (WUE), were measured in the field in this study,. At the same time, we physiological-biochemical parameters, such as the element of leaves, chlorophyll(Chl), soluble sugar, proline(Pro), soluble protein, malondialdehyde(MDA), catalase(CAT) and peroxidase(POD), were monitored indoor. The simulation were applied to the two typical plants sprayed with different concentrations of ferrous sulfate and potassium sulfate solution in the field. At last, photosynthetic, physiological and biochemical parameters of were integrated to evaluate the adaptation of the two plants. The main results are showed as follows:1、The pH of spring water in the YZS pyrite zone was 7.26, but those of the surface water and roadway floor water were less than 3. The total iron content of spring water, surface water and roadway floor water were 11.2mg/L,76.2-520mg/L and 5500mg/L, respectively. The sulfate concentration of spring water was 796.41mg/L, and others ranged from 2378.2 to 20781mg/L. The above results were far beyond the limits specified in the relevant V class water quality standard except the pH of the spring water. And there were severely acidification and dissimilation of the ions in the water quality. The effective sulfur contents of the plot YZS, SYZ and XMZ in the deep soil from 70 to 80 centimeter were 139.46mg/kg,188.5mg/kg and 188.5mg/kg, respectively. And the available soil sulfur index(SAI) were 56.86,76.33 and 77.19 respectively. However, the sulfur content and SAI value in pond bottom mud were reaching up to 1805.4mg/kg and 728.80 respectively. The effective sulfur content in the surface soil was slightly lower than deep soils, but that was far beyond the scope of general plant demand for effective sulfur, forming a distinct sulfur stress. The effective iron content in the surface soil(0 to 15 cm) and pond bottom mud were 20.065mg/kg,33.67mg/kg,34.37mg/kg and 264.81mg/kg, respectively. The iron level reached a high or extremely high level. The mining and smelting of pyrite took serious pollutions to the water and soil environment.2、 The total iron content of Symplocos tetragona Chen et Y.F.Wu fresh leaves was 220.9～495.3mg/kg, litter leaves were 412.1～657mg/kg, while the flower was 2481.5mg/kg; Total sulfur of leaves was 7.2～13.3mg/kg. Those results indicate that Symplocos tetragona Chen et Y.F.Wu has good adaptability for high concentration of iron and sulfur, this is mainly based on the continuous absorption and storage to the available iron and sulfur. The total iron content of Betula luminifera H. Winkl. was 797.8mg/kg, suggesting that it has good adaptability to high concentration of iron.3、Pn, Gs and Tr of Betula luminifera H. Winkl. were greater than Symplocos tetragona Chen et Y.F.Wu in three different pyrite areas(YZS、SYZ、XMZ); Light compensation point(LCP) and light saturation point(LSP) of Betula luminifera H. Winkl.were 19μmol·m-2·s-1 and 1675μmol·m-2·s-1, respectively. Those of Symplocos tetragona Chen et Y.F.Wu were 16 μmol·m-2·s-1 and 1033μmol·m-2·s-1,respectively. Betula luminifera H. Winkl. has a wider range of photosynthesis than Symplocos tetragona Chen et Y.F.Wu. This result indicates that Betula luminifera H. Winkl. is of stronger photosynthetic capacity and adaption to high concentrations of soil iron and sulfur than Symplocos tetragona Chen et Y.F.Wu. The Pn of two kinds of typical plants were significantly affected by Gs and Tr. The Tr in different pyrite zone was XMZ<SYZ<YZS, and WUE was just the opposite. This is mainly due to different pyrite zone with the different pollution levels, so that the vegetation cover and soil moisture are of significant differences.4、In October, the content of chlorophyll(Chl), soluble sugar, proline(Pro), soluble protein, malondialdehydeand(MDA) and the activities of catalase(CAT) and peroxidase(POD) were more 60 percent than in May. This shows that the physiological and biochemical indexes of the typical plants have obvious seasonal variations. And this difference was caused by the accumulation of photosynthesis and the concentration effect caused by the decrease of respiration.5、Integrating the indices of photosynthesis(Pn, Tr, Gs) and physio-biochemistry (chlorophyll, soluble sugar, proline, soluble protein, malondialdehyde, catalase and peroxidase) is to calculate the average of these two typical plants subordinate function values in different pyrite zones by using fuzzy subordinate function. In plots YZS, SYZ, XMZ, the average subordinate function values of Symplocos tetragona Chen et Y.F.Wu are 0.417,0.633,0.504 respectively, and Betula luminifera H. Winkl.,0.474,0.508,0.535, respectively. Reference to the relevant resistance levels, Symplocos tetragona Chen et Y.F.Wu is moderate or higher resistance level in different pyrite zones, but Betula luminifera H. Winkl. is moderate resistance level, and with the contents of iron, sulfur stress strengthening, Betula luminifera H. Winkl. has stronger resistance. These results show that Symplocos tetragona Chen et Y.F.Wu and Betula luminifera H. Winkl. have a comparatively strong physio-ecological adaptability for different pyrite zones, and with different environmental conditions, the adaptation levels of the same specie have changed.