• 关键词：匐枝青藓  铅污染  同步辐射  X射线荧光分析  生物响应

• 基金项目：国家自然科学基金项目(No.10775170);中国科学院知识创新工程重要方向性项目(No.KJCX3.SYW.N3);上海市科委重点项目(No.08390513800);上海市教委科研创新项目(No.09YZ176);上海市重点学科项目(No.S30406)

• 娄玉霞
• 上海师范大学生命与环境科学学院, 上海 200234

• 张元勋
• 中国科学院上海应用物理研究所, 上海 201800

• 俞鹰浩
• 上海师范大学生命与环境科学学院, 上海 200234

• 曹阳
• 上海交通大学生命科学技术学院, 上海 200240

• A.Iida
• Photon Factory, National Laboratory for High Energy Physics, Tsukuba, Ibaraki 305, Japan

• 曹同
• 上海师范大学生命与环境科学学院, 上海 200234

• 摘要：为了研究苔藓植物对铅元素的富集特征和对铅污染的生物响应特性,选用多年生、植株体较大、分布广泛且易于采集的匐枝青藓(Brachytheciumprocumbens)为试验材料,在试验区使用不同浓度(0～3.0mmol·L^-1)的Pb²⁺污染液对人工栽植的匐枝青藓进行了动态胁迫试验(7～28d).使用同步辐射光源的X射线荧光分析技术(SRXRF)测定了植株体内Pb、K、P、S、Fe、Zn等多种元素含量.结果表明,0.2mmol·L^-1的低Pb²⁺胁迫剂量下胁迫生长7d时,植株体内的Pb元素富集量高出对照组29倍,表明匐枝青藓对铅元素具有很强的吸收和富集能力.相关性分析结果表明,藓体内的Pb元素含量与Pb²⁺胁迫剂量和胁迫周期均呈显著正相关.遭受Pb²⁺胁迫状况下,匐枝青藓植株体生长受到抑制,细胞超微结构发生变化,Fe、Ni、Pb等金属离子过量富集;同时,植株体内必须营养元素K、P和Zn的含量显著低于对照,揭示出过量富集的Pb元素对受伤植株体内吸收K、P、Zn等营养元素产生拮抗作用.本研究结果表明匐枝青藓对铅污染的生物响应非常敏感,可作为监测环境铅污染的生物指示植物.

• Abstract：To explore the accumulation characteristics and biological responses to lead in mosses,one widely distributed moss species,named Brachythecium procumbents was chosen. After culturing in special prepared mediums containing 0～3.0 mmol·L^-1 of Pb²⁺ for 7～28 days,the concentrations of chemical elements including Pb,K,P,S,Fe,Zn were analyzed in the whole moss tissues using synchrotron radiation X-ray fluorescence(SRXRF). When grown for 7 days,the content of Pb in the moss tissues under the low Pb²⁺ dosage(0.2 mmol·L^-1) was more than₂₉ times higher than the control. This showed that B. procumbens had a strong absorption and enrichment capacity for Pb. Correlation analysis indicated that the Pb accumulation in the moss tissues had a significant positive correlation with both the Pb²⁺ dosage and the stress periods. Under Pb²⁺ stress,B. procumbens grew much more slowly and the cell ultra-structure was obviously affected. Fe、Ni and Pb were absorbed and accumulated excessively in the moss tissues. However,the essential nutritional elements K,Pand Zn were much lower than in the control. This suggested that excessively accumulated Pb in the damaged plants has an antagonistic effect on the absorption of these nutritional elements. Our results in this work showed the biological response of B. procumbens was very sensitive to the Pb stress,and it could be used as a bio-indicator for Pb contamination in the environment.

• Key words：Brachythecium procumbens  lead pollution  synchrotron radiation  x-ray fluorescence analysis  biological response

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