Lead, Cadmium Stress Response Of Different Genotypes Of Potato Plantlets

Potato (Solanum tuberosum L.) is the fourth important food crop following wheat, corn and rice in the worldwide. With the development of potato production and processing industry in china, potatoes were the most development potential Cultivated crops, as it was more and more important in the increased proportion of food and demand of products exporting. Now, The Pollution of Soil heavy metal in common exist, such as Pb and Cd. The food safety problems caused by Pb and Cd became more seriously, which was concerned by people from all of the world. Here, we used the liquid culture method, Set four Pb and Cd stress level respectively, Dealing with seven genotypes of potato plantlets, Dividing into four periods, in order to examining the biomass and part of physiological index of potato plantlets, The main results and conclusions were as follows:1. In our test, after treated with Pb20d, each genotypes were showed for the inhibition of Plantlet growth (dry weight of Stem and leaf) exception B10, And the higher the concentration the more inhibition were; Meanwhile, treated with Cd40d, each genotypes were showed for the promotion of Plantlet growth (dry weight of Stem and leaf) exception Syl. And the higher the concentration the more promotion were. Analysis that in the liquid culture conditions the Concentrations of Pb may be set high in our test, and the Concentrations of Cd may be low.2. Under the Pb treatment conditions MDA content were higher than control, and MDA content increased with increasing concentrations of Pb. The interaction effects of MDA genotypes and treatment of Pb reached a significant level during each period, It showed that there are obvious oxidative damage between the differences genotypes, treated with Cd after10～30d, the contents of leaf MDA were close to or lower than the control, and with increasing days the trend were declining, However, the MDA levels higher than the control under the40d Cd conditions.3. when MDA content close to or above0.025μmol/g, MDA content were higher than the control in each of Pb and Cd concentrations. Analysis that0.025μmol/g may be the start the regulation of the critical point in the Pb and Cd stress, which were the level of membrane lipid damage and the repair system of the potato plantlets.4. During the periods treatment of Pb, the content of Pro、the effect of SOD activity、 POD activity were all reached a significant or extremely significant level; In which Pro content was significantly lower than control after Processing20d; The activity of SOD significantly higher than that of the control before30d; overall, the activity of POD was higher than the control. In general, SOD and POD were may be the repair mechanism of the start to the Pb stress in the Potato Plantlets. Because of the treatment of Pb and interaction effects of genotypes were all reached extremely significant level, it indicated that under the Pb stress, it may be existed potato genotypes complex toward oxidative damage repair mechanisms.5. The content of Pro, the effect of POD activity were reached a extremely significant level in Cd treatments, also Cd treatments and genotype interaction effect reached a significant level; but SOD activity reached a significant level only in the20d During the periods treatment of Cd. when in the10～30d, Pro content is lower than control,40d close to the control; in the10～30d, SOD activity as a whole is lower than the control, and in the40d of Cd treatment, SOD activity with no significant difference as the control; POD activity in the1Od with the control between the difference was not significant, when in the20-30d, POD activity was significantly lower than control; when in the40d of Cd treatment, POD activity was significantly higher than the control. Thus, POD was may be the repair mechanism of the start to the Cd stress in the Potato Plantlets, But view the degree of stress injury, There may be other repairing, such as protective enzyme or non-enzymatic、phytochelatins.6. In this test, we find that different genotypes of potato plantlets caused the different of the injury response and start of repair mechanism. It is Showed that potato may be has independent of the genetic foundation under Pb and Cd stress, therefore, Molecular genetic techniques should be used on the tested materials.