Studies On Effects Of Zinc And Cadmium On Growth Of The Alfalfa

In our country, water crisis is increasingly serious and the pollution eara of soil heavy metal Cadmium expands continuously. Under this situation, my dissertation studys alfalfa which has good economic value and strong drought and cold resistance. In the study, resistance experiments of heavy metal- Cadmium arid Znic are carried out. It proved that in the scope of experimental concentration the effect which Znic and Cadmium has on alfalfa presents dosage relation. It is known that low concentration of Cadmium and Znic can promote seeds to sprout and seedling to grow; high concentration has restrain effect. In the potted plant experiment, Cadmium has the same effect on sprout rate, root and leave of seedling and seed of alfalfa. The content of Cadmium in the body of alfalfa has relation with the concentration of Cadmium. When the concentration is low, 0-6 mg/kg , the content of Cadmium in the root of alfalfa is lower than in the stern and leaf, but two times higher than the forage hugiene standard of our country. When the concentration is higher than 10mg/kg, the content of Cadmium in the root is 20 times higher than the standard, but the content of Cadmium in the soil decreased obviously, so alfalfa of this condition is the best alternative for renovating polluted soil. When 200mg/kg Znic is added, the poison of Cadmium is decreased dramatically with the grow time increasing, the Cadmium effect on living number decreased. At the same time, the content of Cadmium in the body of alfalfa has decreased, some of them has decreased under standard. The content of chlorophyll and carotenoid in alfalfa decrease when the concentration of Cadmium increased.The effect which Cadmium has on alfalfa of mini-eara is smaller than potted plant because condition is difference.