Adaptive Response Of Enhanced UV-B Radiation For Alpine Plants

The natural environment of Tibetan Plateau is harsh where the alpine meadow indicates seriously deteriorated and UV-B radiation is very strong.They had a profound effect on the flora and fauna of live in the region.In order to study of the adaptive response of the enhanced UV-B radiation on the alpine species of Tibetan Plateau that we use wild legume forages Vicia unijuga A.as research materials with the UV-B radiation level was 6.4KJ.m-2.d-1(simulating a 9%ozone depletion over Gannan of Gansu province,China 340 55'N,2900m)in laboratory conditions.The research content including plant growth,physiological metabolism and molecular control aspects.The results of the study indicated that:1 The resopnse of the Vicia unijuga A.adaptability to enhanced UV-B radiation performance for growth slowed,plant dwarf,biomass decreased,leaf area reduced,leaf shape change narrow and root-shoot ratio increased,etc.2 Enhanced UV-B radiation promotes the content of lignin increased,deposition of thickened in stems and lignification becomes more serious in the Vicia unijuga A.Moreover,the medullary cavity was increase and arrangement of messy in the central of stem.3 High lignification is an adaptive response to enhanced UV-B radiation in the Vicia unijuga A.Collenchyma andxylem vessels had already showed lignification before phloem and metaxylem formed in the tissues.Simultaneously lignin has begun to rapidly generate in the early growth stage.4 Phenolic acid contain ferulic acid and p-counaric acid in the Vicia unijuga A.,but they are very few that is not the main ingredient of phenolic acid.5 The lignin structure of the Vicia unijuga A.mainly is S lignin and S-G lignin;With its growth,lignification degree increasing that is mainly lilac base propane unit(S lignin)that mainly generated by gene CCoAOMT regulation and the high lignification inhibits the growth of plants.6 Plant endogenous hormone ZT,6-BA,GAs,IAA were significantly higher than the control group at the beginning of the enhanced UV B-processing,due to the stress growth.Drops rapidly with the extension of radiation time and significantly lower than the control group,including GAs and IAA is sensitive to UV B radiation,its content change is more intense.Enhanced UV-B processing ABA was not detected in advance,but makes the comparison of the content is significantly higher than control,the Vicia unijuga A.most of strong UV B radiation with the stress response mechanism,make the radiation damage delay.7 Ultraviolet irradiation accelerated the consumption of plant N.N metabolism speeds significantly promoted the generation of lignin.8 The lignin synthesis of the Vicia unijuga A.related genes of CAD in UV B radiation treatment is relatively sensitive,expression is suppressed,the whole process of expression quantity are lower than the control group;F5H gene expression levels.Vulnerable to UV radiation-B inspire CCOAOMT gene,expression,are a key regulation failed and food S lignin synthesis genes.