SRXRF研究苔藓植物对Pb/Fe/Cr污染的生物监视和累积特征

Biological monitor and accumulating characteristic of moss to Pb,Fe,Cr pollution by SRXRF

为研究苔藓植物对环境污染的累积特性和生物监视机理,用加入不同浓度的Pb、Fe、Cr培养基对二代扩繁后的小立碗藓进行胁迫试验,用同步辐射X射线荧光分析技术(SRXRF)测定藓体内金属元素含量,用微束荧光扫描技术(μ-SRXRF)分析了Cr、K等元素在苔藓叶和茎中的精细分布特征。结果表明,在单一重金属或复合重金属元素的胁迫下,藓体内污染金属元素的含量与培养基中相应元素的浓度呈现正相关,小立碗藓的受伤害程度随重金属元素浓度的增加而加重。重金属的胁迫导致小立碗藓吸收K、S等营养元素的能力急剧下降,且小立碗藓茎中K的吸收浓度由于受到过量Cr的拮抗作用而逐步降低。

In order to explore accumulating characteristic of moss as a biological monitor to environmental pollution, cultured Physcomitrella patens of the second generation was grown for 45 days in a specially prepared nutrient medium containing different concentrations of Pb, Fe or Cr, or mixture of Fe-Pb, Fe-Cr and Fe-Cu. Elemental contents in the moss tissue were determined using SRXRF （synchrotron radiation X-ray fluorescence）. Cr and K distributions in leaf and stem of the moss were obtained using micro-SRXRF. The results showed that in the sample groups of both types of the medium containing a single heavy metal or the metal mixture, the contents of polluted metal elements in the moss were correlated to the concentrations of corresponding elements in the culture medium. The moss injury was greatly aggravated with increasing content of heavy metal element. Under the contamination of heavy metals, the ability of moss to absorb nutritive elements （K, S） was declined sharply. Also due to the antagonism of excessive Cr, the content of K element deposited in moss stern decreased gradually.