期刊 Sr^(2+)在印度芥菜幼苗中的富集、亚细胞分布及贮存形态研究  被引量:7

Bioaccumulation, Subcellular Distribution and Chemical Forms of Strontium in Brassica juncea L.

作  者:赖金龙 杨垒滟 付倩[1] 何娇[1] 陶宗娅[1] 罗学刚[2] 

机构地区:[1]四川师范大学生命科学学院 [2]西南科技大学生物质材料教育部工程研究中心

出  处:《农业环境科学学报》2015年第11期2055-2062,共8页Journal of Agro-Environment Science

Bioaccumulation, Subcellular Distribution and Chemical Forms of Strontium in Brassica juncea L.

基  金:国家核设施退役及放射性废物治理科研重点项目(14ZG6101);四川省教育厅理工科重点课题(14ZA0030);四川省教育厅大学生创新创业训练计划项目(201410636040)

摘  要:为研究印度芥菜对Sr2+的富集、转运特性,解释超富集植物对Sr2+的解毒和富集机理,采用水培法培养印度芥菜幼苗至两片真叶,置于含锶[ρ(Sr2+)167(CK)~350 mg·L-1]的营养液中处理7 d后取样,通过差速离心法和化学试剂提取法分离提取植物器官、细胞的亚细胞组分和不同化学形态的Sr2+,原子吸收分光光度法测定各器官(根、茎和叶)、各亚细胞组分及不同化学形态的Sr2+含量。结果显示:印度芥菜各营养器官对Sr2+的富集量为"叶>茎>根",地上部分含量占总含量的84.93%~90.46%,转移系数(TF)达到5.63~9.48;生物富集系数(BCF)达到8.21~12.34;各器官中Sr2+的亚细胞分布主要集中在细胞壁和可溶性组分中,相对含量达到95.62%~100%;细胞核、前质体、叶绿体和线粒体等细胞器仅含少量的Sr2+(<2.92%);Sr2+在印度芥菜根中主要以果胶酸盐、蛋白质结合态或吸附态存在,茎、叶中主要以水溶性有机酸盐和一代磷酸盐的形态存在。研究结果表明:质膜转运蛋白介导的跨膜运输是印度芥菜根系吸收Sr2+的主要途径,将Sr2+以结合态的形式富集到根部,再以水溶态的形式将Sr2+经茎部转运至叶中贮存;同时,通过细胞壁的阻滞作用,将Sr2+结合固定在细胞壁,并将进入细胞质基质的一部分Sr2+转运到液泡内,暂时或"永久性"存贮;通过区域化分布有效降低了细胞器、胞质溶胶(cytosol)及内含物中的Sr2+含量,极大地减缓了Sr2+对细胞器的功能性损伤,此为印度芥菜对耐受Sr2+胁迫的重要机理之一。

This study examined the characteristics of uptake, accumulation, subcellular distribution, and chemical forms of Sr2 +in Brassica juncea seedlings at the two-leaf stage exposed to varying doses of Sr2+[ρ(Sr2+)167(CK)~350 mg·L-1] for 7 days. The accumulation of Sr2+in plant organs displayed the following sequence:leaves > stems > roots. Between 84.93%~90.46% of Sr2+in the plant was accumulated in the aboveground parts(leaves and stems). Translocation factor(TF)and bioaccumulation factor(BCF)of Sr2+were 5.63~9.48 and 8.21~12.34,respectively. Subcellular distribution showed that 95.62% ~100% of plant Sr2 +was localized in the cell walls and soluble fractions, with2.92% of Sr2+accumulated in organelles(including nucleus, chloroplast/proplastid and mitochondrion). Plant Sr2+existed in different chemical forms. In roots, the greatest amount of Sr2+was found in 1 mol·L-1Na Cl-extractable fraction, while most of the Sr2+was extracted by d H2 O in leaves and stems. For Sr2 +uptake by Brassica juncea, Sr2 +was first crossed through root plasma membrane mediated by plasma membrane transporters, combined with pectates and proteins in the roots, and then transported in solution to the leaves. In leaves, most of Sr2+was adsorbed on the cell wall, and Sr2+in the cytosol was transported into vacuoles for provisional or permanent storage. As a result, Sr2+content in organelles was effectively reduced, which may greatly alleviate the damage of Sr2+to organelles. Therefore, Sr2+location in the cell walls and vacuoles may contribute jointly to the accumulation and tolerance of Sr2+in Brassica juncea.

关 键 词: 富集 亚细胞分布 化学形态 印度芥菜 

strontium  bioaccumulation  subcellular distribution  chemical form  Brassica juncea L. 

分 类 号:X503.23[环境科学与工程—环境工程]

 

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