The Effects Of Lanthanum Nitrate On The Active Oxygen Scavenging System And Protein Differential Expression Of Hevea Latex

Natural rubber has a high economic value and prospects of the global industrial raw materials, and is an indispensable strategic material. The main source of natural rubber is Hevea brasiliensis. Currently, ethephon stimulated tapping technique has been widely used in the production. However, in the production process of rubber trees, tapping and ethephon are both harmful to the bark tissue and affect the physiological metabolism of rubber trees. Ethephon compound agents can greatly reduce the side effects of ethephon. Today, rare earth nitrate and cheiated rare-earth molybdate are commonly used as ethephon compound agent, which containing rare earth elements.Treatments with ethephon, lathanum nitrate and mixture of ethephon and lathanum nitrate were applied on the open-cut trees, latex peroxidase (POD) activity, superoxide dismutase (SOD) activity, ascorbic acid (Vc) content, thiol content, protein content, dry rubber content, total solids content, and dry rubber production and other physiological parameters were determined. The differential expression of latex proteins were analyzed by 2-D electrophoresis and mass spectrometry.It was found that ethephon lanthanum nitrate treatment's POD specific activity was significantly lower than the application of ethephon only. The latex SOD specific activity of the application of lanthanum nitrate was significantly higher than the application of ethephon only. Lanthanum nitrate did not increase latex Vc and thiols content; lanthanum nitrate combined with ethephon had no effect on the latex Vc content; lanthanum nitrate combined with ethephon did not increase latex thiols content than that of ethephon treatment. Applied with lanthanum nitrate, the antioxidant capacity of rubber trees may be mainly improved by enzymatic oxygen species scavenging system, but not the non-enzymatic system.Dry rubber content, total solids content and dry rubber production of each treatment were compared and analysed. The results showed that lanthanum nitrate was no significant effect on the yield of rubber tree latex, while the potential of producing latex of rubber trees was protected by the application of lanthanum nitrate during tapping.TCA-acetone precipitation was used on extracting the whole latex protein. After 2-DE including isoelectric focusing (pH5-8,17 cm IPG strip) and SDS-PAGE (12.5% gel concentration), PDQuest software was used to analyze the differential protein spots, consequently to be identified by MALDI-TOF and MASCOT. Although La probably has no direct contribution to the rubber production, could be used to reduce the the damage to rubber tree of the ethephon as an compound agent.