Several Mosses To Heavy Metal Stress Response

Many heavy metals like lead, mercury, cadmium, cobalt and so on enter in the atmosphere, the water, the soil because of heavy metal mining, smelting, processing and commercial manufactures. The heavy metal pollution have characteristics of confidentiality, permanence and irreversibility, and the human body health is affected through food chains. Therefore heavy metal pollution monitor and prevention is one of the most important topics of urban environment protection. In this paper, bryophyte gametophytes at Laoshan Mt. were selected as the experimental materials at Laoshan Mt. We studied the heavy metal enriching power and adsorption characteristic of the different bryophytes, cell distributed characteristic of different heavy metals and effect of heavy metal stress on chlorophyll fluorescence parameters in bryophyte. The results were listed as follows:1.Heavy metal content was researched between 2008 and 2009 in the bryophyte. The results indicated:(1)The bryophyte is the good indicator plant of environment quality, which not only shows the environment heavy metal pollution in the present situation, but also can be as a long-term monitor of environmental variation. Looking from the heavy metal content of bryophyte and soil at Laoshan, the heavy metal Zn content is the highest, the Cd content is the lowest, the Pb and the Cu content is close. The Pb and the Cu content in the environment in 2009 is more than that in 2008 at Laoshan. But as a whole, Qingdao has the good air quality.(2) Different species of bryophytes had different adsorptive ability to the same metal, and the same bryophyte had different adsorptive ability to the different heavy metals.(3)The difference of concentrates ability which different species of bryophyte has to the same metal is extremely remarkable. It is suggested that the moss Hypnum plumaeforme and Grimmia pilifera could be used as bioindicators in monitoring for the heavy metals pollution. The bryophyte of lithophilic habitat compared to locally born has the stronger accumulation ability. Grimmia pilifera ability is the strongest.2.Adsorption characteristic in two mosses Hygrphpnum eugyrium(B.S.G.) and Atrichum umdulatum(Hedw.)P.Beauv. to the stress caused by singed Pb, Cd, Cu and Zn have been investigated. The results indicated:the bryophytes' adsorption dynamics to heavy metal could be carved into two stages, the rapid reaction phase and slow reaction phase. Different species of bryophytes had different adsorptive ability to the same metal, and the same bryophyte had different adsorptive ability to the different heavy metals. The capacity of the bryophytes adsorption to the heavy metal enhances along with the processing solution concentration increases.3.Cellular distributed characteristic in two mosses Hygrphpnum eugyrium(B.S.G.)and Atrichum umdulatum (Hedw.)P.Beauv. to the stress caused by singed Pb, Cd, Cu and Zn have been investigated. The results indicated:the massive heavy metals mainly distributed in the extracellular sites, and heavy metals of intracellular, especially particulate proportion are few. Cellular distributed characteristic were varied among different heavy metal species, indicating proportion is related to the heavy metal type.4.The response mechanisms of antioxidative systems in three mosses Hygrphpnum eugyrium (B.S.G.),Atrichum umdulatum(Hedw.)P.Beauv. and Hypnum plumaeforme Wils.to the stress caused by singed Pb,Cd,Cu and Zn have been investigated. The results indicated:(1)Heavy metals stress induced dose-dependent and time-dependent decline of chlorophyll fluorescence parameters in three mosses. (2) Different species of bryophytes had different tolerance to the same metal, and the same bryophyte had different tolerance to the different heavy metals. Atrichum umdulatum had a certain tolerance in Pb. The single heavy metal Cd and Cu had a more impact on photosynthesis in three mosses than the single heavy metal Pb and Zn.(3)The decline of their chlorophyll fluorescence parameters were related to the concentration of heavy metal and the processing time. Single Pb, Cd and Cu resulted in a decline of chlorophyll fluorescence parameters of Fv/Fm,ETo/TRo,RC/CSo and ETo/ABS.ETo/ABS and RC/CSo are more sensitive than other parameters, which may reflect the endurance of bryophyte under the heavy metal stress.