Study On Accumulation Effect And Stress Response Of Macleaya Cordata To Mn

In recent years,the soil heavy metal pollution situation is more and more serious,endangers the human health.Phytoremediation technology,with its advantages of green,economical and in-situ treatment and remediation,has aroused extensive research and discussion in the field of preventing and controlling soil heavy metal pollution.Based on Macleaya cordata as the research object,the plants were treated with different concentrations of Mn,after 60 days of sand culture experiment,by measuring their biomass,plant height,branch number,total root length and plants Mn accumulation,activity of antioxidant enzyme system level,antioxidant content,pigment content,photosynthetic efficiency and the fluorescence parameters,explore the exogenous Mn on bo fall back into the effects of plant growth and physiological and biochemical indexes,clear plant’s capacity to absorb and enrichment of Mn,obtain the following results:(1)the low concentration of Mn(1000μM and 5000 p.M)promoted the growth of rhizome plants,and increased their biomass,plant height,total root length and number of plant branches;High concentrations(10,000 μM,15,000μM,20,000 μM)inhibited growth and reduced biomass.The critical concentration of Mn tolerance of c.microflora growth was 5000 μM.(2)the content of Mn in the root,stem and leaf tissues increased significantly with the increase of Mn concentration,and the increase of Mn content in the leaves was the most significant.The order of the strength of Mn accumulation and storage was;leaf>root>stem;The enrichment coefficients of the three tissues were all>1,which indicated that the enrichment ability of Mn was strong.(3)Mn is mainly distributed in the cell wall,followed by the soluble part of cytoplasm;Mncontent in leaves and stems increased with the increase of exogenous Mn concentration,while Mn content in other parts decreased.Mn content in root cell wall and cytoplasmic soluble substances(including vacuoles)increased with the increase of exogenous Mn concentration,while Mn content in other organelles(except vacuoles)decreased.(4)Mn mainly exists in the form of acetic acid state and sodium chloride state in the leaves,accounting for 41,51%-60.49%.Mn mainly exists in the form of water state and sodium chloride state in the stem,accounting for 39.61%-43.28%.In the root system of Mn,water extraction is the main state,accounting for 24.64%～27.98%.(5)low concentration of Mn increased the content of chlorophyll,carotenoid,soluble protein and free proline in the leaves of Macleaya cordata,while high concentration of Mn reduced the content.Mn of different concentrations increased MDA content in the leaves of the fallow plants,and the promotion effect was positively correlated with Mn concentration.(6)low concentration of Mn increased the activity levels of SOD and POD in the leaves of Macleaya cordata,while high concentration of Mn decreased the activity levels of both enzymes;Different concentrations of Mn reduced the activity level of CAT in the leaves of fallow plants,and the inhibitory effect was positively correlated with Mn concentration.(7)exogenous Mn can improve the Ci value of the plant leaves,but has no significant effect on the Ls value;Exogenous Mn can reduce the Fv/Fm,qP,ΦpPSⅡ and ETR values of the returned blade;Increases the NPQ value.To sum up,Macleaya cordata can be used as a plant for phytoremediation because of its strong ability to enrich Mn.