Operation And Evaluation Of Antioxidant Systems In Root Tips Of Four Eucalyptus Seedlings Under Aluminum Stress

With the development of industrial level and the deepening of atmospheric acidification,aluminum pollution has become more and more serious.In the ecological restoration of urban polluted land in recent years,early fast growing plants can lay a solid foundation for future landscape construction and environmental improvement.Aluminum resistance in order to select excellent varieties of Eucalyptus,and understand the oxidation of aluminum resistance strength tree system working principle,this paper through the study of four different genotypes(Eucalyptus urophylla,Eucalyptus umbellate,Eucalyptus grandis and E.urophylla×E.grandis)from Eucalyptus aluminum resistance the root of the difference and antioxidant system differences and the damage of multiple indexes such as appearance,with the help of analysis of the growth of roots and the root of the evaluation of physiological and biochemical indexes,to observe the cell staining methods after comprehensive analysis draws the following conclusions:1.All four species of eucalyptus seedlings can produce responses to aluminum stress within 24 hours,which is most directly reflected in the effects on root elongation and root activity,as well as physiological indicators of plant roots and leaves.2.The research of four kinds of Eucalyptus seedlings under 24 hours 4.5m M Al3+ stress showed significant difference of aluminium resistance,through the roots and leaves of proline,soluble protein,soluble sugar,malondialdehyde and polyphenol oxidase content change indexes such as correlation analysis and membership function analysis,four types of Eucalyptus aluminum resistance:E.urophylla×E.grandis > Eucalyptus urophylla> Eucalyptus grandis>Eucalyptus umbellate.The hybrid E.urophylla×E.grandis is the most tolerant to aluminum toxicity and is suitable for planting in high aluminum polluted land.3.Eucalyptus seedlings was being forced to produce large amounts of ROS and RNS,the fluorescence microscopic observation shows its produce on the root tip cell division active region,and through to the dead cells in accordance with Evans blue staining and schiff’s reagent on MDA location observation is that the quantity of ROS and RNS and parts and the quantity of dead cells and MDA and parts were positively correlated.4.The production of ROS and RNS can activate the operation of the antioxidant system and the anti-nitrosation system of root tip cells,and the defense system of the aluminium-resistant tree species against aluminum toxicity stress is significantly different from that of the aluminium-sensitive treespecies.The root tips of aluminum-tolerant Eucalyptus seedlings,such as E.urophylla×E.grandis and Eucalyptus urophylla,were rapidly and significantly enhanced with CAT,SOD,As A,GSNOR and other key enzymes or non-enzymatic substances to clear the excessive accumulation of ROS and RNS and resist oxidative stress and nitrosation stress.On the other hand,aluminum-sensitive eucalyptus trees such as Eucalyptus umbellate and Eucalyptus grandis produced more NADPH oxidase to accelerate the accumulation of ROS,while a small amount of GSNOR,SOD and GSH led to the excessive accumulation of RNS,resulting in double damage.5.Antioxidant system response speed and higher antioxidant levels and resistance to aluminum,aluminum resistance strong genotypes of Eucalyptus root tip cells of As A and GSH loop response more quickly and its metabolites in the process of secretion is more vigorous,and by maintaining a high level of antioxidants such as APX,As A,GSH,etc to make a defense of the oxidative stress.