Study On Rapid Propagation Of Bryophytes And Enrichment Characteristics Of Radon

Aiming at the key technical issues of uranium tailings and the surrounding environment airborne radioactive Rn pollution control,this paper uses four wild-type bryophytes growing in a uranium tailings area as materials,through identification and research of its rapid propagation technology;After treatment with different gradient concentrations of uranium stress,different treatment times,etc.,the U enrichment method and enrichment of one of the main nuclides of uranium tailings radon source by four bryophytes were analyzed,and their antioxidant enzymes?SOD,POD,and CAT?activity were measured and analysis of its enrichment characteristics;use the FD-216 environmental radon measuring instrument to measure the radon concentration changes of the 4 bryophytes covering the surface of the uranium tailings within 8 hours,and analyze the microstructure and enrichment characteristics of the bryophytes leaves after radon adsorption.The aim is to be able to cultivate a large number of bryophytes to cover the surface of uranium tailings in a short time,and provide a certain reference for the control and treatment of airborne radioactive Rn pollution in uranium tailings and the surrounding environment.The main findings are as follows:?1?4 types of wild-type bryophytes collected from uranium tailings are analyzed through comparative analysis of their microscopic and macroscopic community structures,combined with the description of the species in Volumes 1 to 10 of?Chinese Moss Atlas?,identified as:Hypnum cupressiforme L.ex Hedw.Var.Cupressiforme,which belongs to Orders HYPNOBRYALES,Families Hypnoideae,and Genus Hypnum Hedw;?2?Hypnum plumaeforme,which belongs to Orders HYPNOBRYALES,Families Hypnoideae,and Genus Hypnum Hedw;?3?Plagiomnium acutum?Lindb.?T.Kop.,which belongs to Orders EURYALES,Families Mninceae,and Genus Plagiomnium T.Kop.;?4?Taxiphyllum taxirameum?Mitt.?Fleisch.[Stereodon taxirameus Mitt.],which belongs to Orders HYPNOBRYALES,Families Hypnoideae,and Genus Taxiphyllum Fleisch..Under the conditions of light intensity 36?mol photons·m^-2·s^-1,light time 16 h,and humidity 75%,the combination of factors and levels most suitable for rapid reproduction is obtained:Hypnum cupressiforme L.ex Hedw.Var.Cupressiforme(pH 6.5,20°C,red jade soil,Brassinolide 20mg·L^-1),Hypnum plumaeforme(pH 5.5,20°C,red jade soil,Brassinolide 20 mg·L^-1),Plagiomnium acutum?Lindb.?T.Kop.(pH 5.5,20°C,red jade soil,Brassinolide 40 mg·L^-1),Taxiphyllum taxirameum?Mitt.?Fleisch.[Stereodon taxirameus Mitt.](pH 6.5,20°C,red jade soil,DA-6 5 mg·L^-1).?2?The release of Rn from uranium tailings originates from the decay of radionuclides uranium,thorium,radium,etc,among which the decay of uranium becomes the main.Through the adsorption and enrichment of uranium by bryophytes,the total release of Rn can be controlled or reduced from the source.The U enrichment of 4 bryophytes was positively correlated with the concentration and treatment time of uranium stress.The ability of 4 species of bryophytes to accumulate U was negatively correlated with uranium stress time and concentration,and the effect of uranium stress concentration on the ability of bryophytes to accumulate U was greater than the uranium stress time.The adsorption and enrichment of U by bryophytes is mainly based on extracellular enrichment,supplemented by intracellular absorption.Its total U enrichment capacity is 116.15?g·g^-1169.03?g·g^-1,and its U enrichment capacity:Hypnum cupressiforme L.ex Hedw.Var.Cupressiforme>Taxiphyllum taxirameum?Mitt.?Fleisch.[Stereodon taxirameus Mitt.]>Plagiomnium acutum?Lindb.?T.Kop.>Hypnum plumaeforme.The activities of SOD in four bryophytes were negatively correlated with uranium stress concentration and positively correlated with uranium stress time;POD and CAT activities were positively correlated with low concentration gradient(?100 mg·L^-1)uranium stress and high concentration gradient(?100 mg·L^-1)Uranium stress is negatively correlated with uranium stress time.The relationship between SOD stress and uranium stress concentration of4 bryophytes is opposite to the change trend of their activities,and the relationship between POD and CAT stress and uranium stress concentration is the same as their activity change trend.The stress of 3 antioxidant enzymes and uranium stress time There is a negative correlation,and the effect of uranium stress time on the resistance to oxidative enzyme stress is greater than the concentration.The stressors are:Hypnum plumaeforme>Plagiomnium acutum?Lindb.?T.Kop.>Taxiphyllum taxirameum?Mitt.?Fleisch.[Stereodon taxirameus Mitt.]>Hypnum cupressiforme L.ex Hedw.Var.Cupressiforme.Resistance to stress:Hypnum cupressiforme L.ex Hedw.Var.Cupressiforme>Taxiphyllum taxirameum?Mitt.?Fleisch.[Stereodon taxirameus Mitt.]>Plagiomnium acutum?Lindb.?T.Kop.>Hypnum plumaeforme.?3?The field study of uranium tailings by bryophytes to control radon gas varies with the species of bryophytes,the uranium tailings are covered with bryophytes to control the release of radon:Hypnum plumaeforme>Hypnum cupressiforme L.ex Hedw.Var.Cupressiforme>Plagiomnium acutum?Lindb.?T.Kop..Within 8 hours,the radon concentration(>200Bq·m^-3)in a confined space per unit volume decreased:44.88%⁷6.82%,and its effect on the release of radon was extremely significant.The bryophytes have a certain ability to accumulate Rn,and accumulating in the environment because of its water absorption characteristics.The presence or absence of domestication of bryophytes,leaf surface area,leaf roughness,and water absorption are all factors that affect the ability of bryophytes to absorb and accumulate Rn.