Initial Study On Ecological Restoration Of Chengchao Iron Mine Tailings, In Hubei Province

Metal mine waste tailing dumps are a typical degenerated ecosystem, and at first the restoration of them depends on the ecological restoration of vegetation, or rehabilitation. Later the quantity and species of soil animal and microorganism increase with the development of vegetation, and in the end the ecological system will be restored. In this paper we did some ecological research on the vegetation of rehabilitation in the field of Chengchao Iron Mine tailings, Hubei Province. The result shows that it is a better measure of ecology restoration to plant Robinia pseudoacacia L. in the wasted iron mine tailings. In the drought condition, the plants of Gramineae and Compositae are the pioneer species, while in the wetland environment Typha orientalis Presl and Phragmites communis Trim are the first species that reside in the tailings. The disturbance of human action can accelerate the restoration process of the vegetation.Moreover, through pot culture experiments, comparative study on the effects of iron mine tailings on growth and development and physiological function of three kinds of plants was done and the physiological and biochemical mechanism of metal tolerance of them was analysed in this paper. At the first step of the experiments, we selected eight species of plants to do the tests of germination percentage and survival percentage of seedlings. From which we selected three species to do further study, such as the free proline content, chlorophyll contents, the solvable protein contents, polypropylene-amide erect-board electrophoresis analysis of four isozymes (peroxidase, POD; catalase, CAT; esterase, EST; superoxide dismutase,SOD), activities of three enzymes (POD, EST and SOD). The three species of plants are Peanut (Arachis hypogaea L.) and ArudS (Festuca arundinacea Schreb cv. Arud3), Triple A (Festuca arundinacea Schreb cv. Triple A) Three treatments, X-M 100(100% tailings), X-M50(mine spoil -soil mix in the volume ratio of 1:1, 50% tailings+50% soil) X-M00(100% soil) were designed and each treatment was repeated four times. The following are the results of the initial comparative study:1) If there is suitable quantity of water, the seeds can germinate, and in the experiment we find it seems that the pure iron mine spoil will do health to thegermination of plants.2) Wasted mine tailings do harm to the growth and development of plants considering the physiological characteristics of survival percentage of seedlings, free proline content and chlorophyll contents. The survival percentage of seedlings and chlorophyll contents rise with the increase of the percentage of wasted mine tailings, and the change of free proline content is on the contrary.3) There is no significant difference of SDS protein band among three treatments of each plant. Most of proteins are small molecular weight ones, and their molecular weights are in the range of 14-31kD. However, the concentration was different, which can be confirmed by the solvable protein contents measured by the method of Lowery.4) Some difference of activities of three enzymes (peroxidase, esterase and superoxide dismutase) is observed between treatments, but it is not significant. At the same time, by using polypropylene-amide erect-board electrophoresis, four isozymes (peroxidase, catalase, esterase and superoxide dismutase) were analyzed. There was no electrophoretic difference among three treatments of each plant and the enzyme-bands are same.5) The above study showed that there is only a little difference between Triple A and Arud3 in some kinds of results, but there is significant difference between Peanut and in all kinds of results, include SDS-PAGE bands and four isozymes bands. The reason is that Triple A and Arud3 are two cultivated species of Festuca arundinacea Schreb. In a word , we think that Peanut, Triple A and Arud3 all can be used as pioneer species in the tailings, in which, Peanut is the most suitable one.