Experimental investigations of five different mosses on accumulation capacities of Cu,Pb and Zn

Uptake of Pb, Cu and Zn by different epiphytic moss species Floribundaria floribunda (Doz. &; Molk.) Fleisch., Taxiphyllum giraldii (C. Muell.) Fleisch. and Thuidium sparsifolium (Mitt.) Jaeg., an epilithic moss Thuidium delicatulum (L.) Mitt. and a leafy liverwort Ptychanthus striatus (Lehm. &; Linderb.) Nees. was studied experimentally. The plant bodies were treated with single metal and mixed metal solutions of Pb(NO₃)₂, CuCl₂ and ZnCl₂ at different concentrations ranging from 10^?10 to 10^?2 mol L^?1. Higher uptake of Pb, Cu and Zn by T. giraldii, T. sparsifolium and P. striatus than by F. floribunda and T. delicatulum was shown in both treatments. Compared with the single metal treatment, the uptake of Zn was very low at higher concentrations in the mixed metal treatment. A slight depletion of Zn was noticed in the long-term exposure. Leaching of naturally accumulated Zn from the mosses and leafy liverwort was also observed when treated with higher concentrated (10^?4, 10^?2 mol L^?1) Pb(NO₃)₂ and CuCl₂ solutions. Similarly, the leaching of naturally accumulated Cu was observed in leafy liverwort P. striatus with 10^?2 mol L^?1 Pb(NO₃)₂ and ZnCl₂ treatments. However, insignificant changes were observed on naturally accumulated Pb and Cu in mosses. From these experiments, the epiphytic mosses T. giraldii and T. sparsifolium, which have high Cation exchange capacity and large leaf surface area, have been found to be suitable for assessing heavy metal concentration in a moderately or slightly contaminated environment.     

生长条件对苔藓硫含量和硫同位素组成指示大气硫沉降的影响

对相同大气沉降和土壤背景但生长条件不同的苔藓w（S）和δ（34S）进行了分析. 土生苔藓w（S）高于石生苔藓,表明土壤对苔藓w（S）指示大气硫沉降有影响. 受树冠遮挡的苔藓w（S）偏低反映了树冠吸收会削弱冠下的大气硫输入,而不同类型树冠对大气硫的截留吸收程度不同,这可能是造成树冠下方苔藓w（S）存在差异的主要原因,但随树冠厚度变化无明显规律.石生苔藓δ（34S）与大气硫δ（34S）吻合,而土生苔藓δ（34S）明显受土壤硫的影响而偏正. 此外,树冠下苔藓δ（34S）偏高还与树冠吸收大气硫的过程中发生34S歧视有关,苔藓δ（34S）随树冠厚度增加而偏正,进一步证实了树冠的长期吸收会使沉降到树冠下的大气硫源δ（34S）偏正. 因此,受生长条件歪曲了的苔藓w（S）和δ（34S）不能用于解释大气硫沉降的变化和来源,开阔地的石生苔藓比土生苔藓和受树冠遮挡的苔藓更具有大气指示意义.