Effects Of Heavy Metals Stress On The Growths,Pigment Contents And The Absorption Characteristics Of Heavy Metals In Corn (Zea Mays L.)

Heavy metals Pb,Cu is a kind of heavy metal pollutants,When the content exceeds a certain threshold concentration in plant,plant toxicity,the plant will produce toxic effects,light can cause plant metabolism process disorders,growth and development blocked,also can lead to plant death when on deep hurt,And heavy metals Pb,Cu poisoning will also cause some of the plant oxidation stress response.The correlation between the accumulation of heavy metals and the secretion of cytochrome in maize was provided by maize plants under heavy metal stress,which provided scientific basis for the resistance of heavy metals in maize and its resistance mechanism.The main findings are as follows:1.The influencing mechanism stress to study the effects of different varieties of maize on Cd?Pb?Cu?Zn and adsorption of heavy metal had been investigated by potting test experiment.Different varieties of corn were Li-Yu16,Zhong-dan909,Lu-Dan981,Zhong-Ke 4,Zheng-Dan958,Deng-Hai605.The results showed that the variation coefficient of available heavy metals in different soil maize was Pb>Zn>Cu>Cd,and the variation of available Pb in soil was 31.59⁶0.11,the coefficient of variation was 0.22,The variation coefficient of Cu is 13.70²0.65,the coefficient of variation is 0.17,and the coefficient of variation of the whole coefficient is lower.During the jointing period,the total Cd content of maize was 903,the highest was 0.31 mg·kg^-1,and the Pb content in Luban 981 was 1.73 mg·kg^-1,and Pb,Zn,Cu and Cd The enrichment coefficient of heavy metals is less than 1.0.At the time of harvest,the accumulation of four heavy metals was lower than that of Zhengdan 958,and the transfer coefficient of heavy metals was less than 1.0.2.The accuracy of anthocyanin and?-carotene assay in maize was studied by high performance liquid chromatography?HPLC?.The antioxidant activity of anthocyanin and?-carotene was studied by UV method.The results showed that the detection limit of anthocyanin was high in the concentration range of 0 mg·L^-1100 mg·L^-1,and the detection limit of?-carotene was determined by high performance liquid chromatography at 0.25 mg L^-125 mg·L^-11 concentration,the recovery rateof80%ormore.Theabilityofanthocyaninsand?-carotenetoremove DPPH·?1,1-diphenyl-2-trinitrophenylhydrazine?indicates that both have antioxidant ability.The highest DPPH scavenging rate was 95%at the concentration of 50 ug·mL^-1,higher than that of Vc?ascorbic acid?on DPPH·clearance.?-carotene at a concentration of 25 ug·mL^-11 for DPPH·clearance up to 36%,higher than BHT?dibutylhydroxytoluene?on DPPH·clearance.The antioxidant capacity of anthocyanins is higher than that of beta-carotene.3.The influencing mechanism of Pb and Cu stress to the corn's growth,synthesis of cytochrome and adsorption of heavy metal had been investigated by hydroponics experiment.The results showed that,single stress of heavy metal Pb or Cu led to a relatively lower root length of corn,while Pb and Cu combined stress experiment demonstrated a negative correlation between the root length and compound concentration.The biomass of corn samples remained relatively stable in single stress experiment of Pb or Cu,just increased firstly and then decreased with the increase of heavy metal Pb or Cu concentration.The content of chlorophyll presented a negative correlation with Cu concentration,and a positive correlation with Pb concentration.The content of?-carotenoids in single stress experiment of Pb or Cu,just increased firstly and then decreased with the increase of heavy metal Cu concentration,on the contrary with the increase of Pb concentration,the?-carotene decreased firstly and then increased.The content of anthocyanin increased relatively in the single stress treatment of Pb or Cu,but the increased extent caused by Cu stress was more significant,with the lowest increase of 0.65%and the highest increase of 21.25%;The adsorption abilities of different corn organs to heavy metal Pb and Cu exhibited some differences.The accumulation of heavy metals in corn?root>stem and leaf?kept positive correlation with the treatment concentrations.The absorption abilities of roots gradually increased with the increase of heavy metal Pb and Cu combined stress,while absorption of stems and leaves remained relatively stable.This indicated that the abilities of corn plant to migrate and accumulate heavy metal were stimulated by Pb and Cu combined stress.The correlation analysis between cytochrome synthesis and heavy metal indicated that the synthesis of corn cytochrome depend on the metal types.There was significant correlation between Pb content and?-carotenoid content,While Cu content was significantly correlated with anthocyanin content.Revealed that Pb exerted more effects to induce?-carotenoids,while Cu made much more important roles to induce anthocyanins.All of these provide scientific basis for plant heavy metal toxicity and resistance mechanism.