Effect of cadmium on seed germination and seeding growth of pumpkin

The pollution of cadmium has a serious influence on most organisms and cadmium has a large bioaccumulation. When the cadmium toxicity reached a certain degree, there will be a series of disease performance for example, yellow leaves, chlorotic dwarf plants and other symptoms of poisoning. All in all, it has a serious impact on quality and yield of crop. At present, the research on the effect of heavy metal pollution on the plant growth is getting more and more attention. The pumpkin seeds were treated with cadmium chloride solution 0, 2, 5, 10, 20, 40, 80, 120, 200 and 300umol/L respectively. The results showed that when the concentration of cadmium was lower than of 20umol/L, the germination rate increased with the increase of cadmium concentration and over this cadmium concentration, the situation is the opposite. Under high concentration stress, the average length of root length was decreased but fresh weight was not changed. The seed vigor index and germination index of pumpkin decreased with the increase of cadmium concentration. Moreover, under the environment of low concentration cadmium stress, the activity of POD and CAT decreased. The content of soluble protein increased with the increase of Cd concentration when the concentration of cadmium was low. After the concentration of more than 20umol/L, the content of soluble protein decreased with the increase of cadmium concentration. It indicated that stress environment has obvious effect on the content of soluble protein in plant. All in all, the activity of the leaf oxidase plays an important role in the cadmium toxicity.