The Tolerance Research Of Polypogon Fugax N From Different Regions Under Cu²⁺ Stress

Trace Element Cu is essential to plant growth. Appropriate amount of Cu can promote plant growth, but more Cu will produce toxic effects on plants. In recent years, soil is polluted by more and more Cu, the yields and quality of crop is gradually declining, the quality of people′s life is seriously affected by it.Polypogon fugax N from different regions were elected as experimental materials. Under different Cu²⁺ sress, the seed germination and the physiological and biochemical characters were studied. The results showed as the following:1. The seed germination and plant growth were promoted under lower Cu²⁺ sress, but they were seriously inhibited along with the increasing of Cu²⁺ sress. Toxcity of Cu²⁺ on root was more serious at the sametime. Two populations of polypogon fugax N were compared, polypogon fugax N from the mining area was less affected under Cu²⁺ sress.2. Pot experiments: the contents of chlorophyll, soluble protein, soluble candy in two populations of polypogon fugax N were enlarged; membrane permeability and MDA content were less changed; SOD activity was gone up; the effection of POD and CAT activities was not significant under lower Cu²⁺ sress. With the increasing of Cu²⁺ sress, the contents of chlorophyll, soluble protein, soluble candy in them were gradually reduced; membrane permeability and MDA content were lager. SOD activity was seriously gone up, but the activity was notably dropped under 500mg/kg Cu²⁺ sress; POD and CAT activities were going up. Overall, the effection of the physiological and biochemical characters was different under different Cu²⁺ sress. The contents of chlorophyll, soluble protein, soluble candy and SOD activity were promoted under lower Cu²⁺ sress, but they were inhibited under higher Cu²⁺ sress. The membrane permeability, MDA content, POD and CAT activities were not clearly affected under lower Cu²⁺ sress, they were seriously enlarged under higher Cu²⁺ sress. Two populations of polypogon fugax N were compared, the effection of Cu²⁺ sress on the physiological and biochemical characters was smaller in the polypogon fugax N from the mining area.3. The results of the experiments show that: Cu²⁺ tolerance of polypogon fugax N is different as regional difference. The polypogon fugax N from the mining area may form their own specific resistance system to copper toxicity, due to long-term living in the environment polluted by copper. Such as, under different Cu²⁺ sress, the activities of SOD, POD and CAT were higher in the polypogon fugax N from the mining area. They can efficiently remove large quatities of free radicals in the body. The content of soluble protein was higher under Cu²⁺ sress,it can bind with Cu²⁺ and effectively reduced Cu²⁺ toxicity, indicating, the polypogon fugax N from the mining area has adapted the environment polluted by copper, it has become a kind of copper-resistant plant.