两种生态型香根草对镉的耐受和积累特性比较  

Comparative Tolerance and Accumulation Characteristics of Cadmium in Two Vetiver Grass Ecotypes

作　　者：董名扬 孙瑶 冯晓晖 汪毅 胡斌 周强[1,2] DONG Mingyang;SUN Yao;FENG Xiaohui;WANG Yi;HU Bin;ZHOU Qiang(Key Laboratory of Plant Resources Conservation and Utilization,College of Hunan Province,Jishou University,Jishou 416000,China;Hunan Provincial Engineering Laboratory of Control and Remediation of Heavy Metal Pollution from Mn-Zn Mining,Jishou,Hu nan 416000,China)

机构地区：[1]吉首大学植物资源保护与利用湖南省高校重点实验室,湖南吉首416000 [2]锰锌矿业重金属污染综合防治技术湖南省工程实验室,湖南吉首416000

出　　处：《西北植物学报》2022年第8期1330-1338,共9页Acta Botanica Boreali-Occidentalia Sinica

基　　金：国家自然科学基金(31860117,31300337);吉首大学研究生科研创新项目(JGY202169)。

摘　　要：以Monto和Veriveria nermorlis两种生态型香根草[Chrysopogon zizanioides(L.) Roberty]为材料,采用室内水培试验,在不同浓度(0、200、800、2 000μmol·L^(-1))硝酸镉溶液处理7 d后,比较、分析两类型香根草的叶片生长状况、叶绿素荧光参数、镉的积累、亚细胞分布和化学形态分布等指标的差异,明确两类香根草对镉的耐受能力和积累特性。结果表明,(1)在中度(800μmol·L^(-1))和重度(2 000μmol·L^(-1))镉胁迫条件下,Monto的叶片生长状况优于Veriveria nermorlis,其F_(m)、F_(v)/F_(m)和F_(v)/F_(o)等叶绿素荧光参数显著高于Veriveria nermorlis,而其叶片、根部镉含量、富集系数和镉转移系数则显著低于Veriveria nermorlis。(2)镉主要分布在香根草根和叶细胞壁组分和可溶性组分中,两者镉含量占比之和达95%以上;对于两种生态型香根草的叶片和Monto的根部而言,细胞壁组分和可溶组分镉占比随着镉胁迫浓度增加分别呈增加和下降趋势,但两参数在Veriveria nermorlis根中的变化趋势则相反;Monto叶中细胞壁组分的镉占比要高于Veriveria nermorlis。(3)镉的化学形态分布分析显示,两种生态型香根草叶片中以氯化钠提取态镉为主,而根中以乙醇提取态和氯化钠提取态镉为主;Monto根中乙醇提取态的镉含量占比远大于Veriveria nermorlis。研究发现,Monto香根草的镉耐受能力较强,主要因为其根、叶中的镉积累量、镉富集系数和转移系数均低于Veriveria nermorlis,且Monto叶片中细胞壁组分的镉占比和根中乙醇提取态镉的占比更高。In this study, Monto and Veriveria nermorlis ecotypes of vetiver grass [Chrysopogon zizanioides(L.) Roberty] were treated with cadmium nitrate solution at different concentrations(0, 200, 800, 2 000 μmol·L^(-1)) for 7 days. We compared and analyzed the differences of leaf growth status, chlorophyll fluorescence parameters, cadmium accumulation, subcellular distribution and chemical forms distribution between the two vetiver ecotypes to determine the tolerance and accumulation characteristics of the two types of vetiver grass to cadmium. The results showed that:(1) under middle and high cadmium concentrations, the growth status of Monto was better than that of Veriveria nermorlis, and the chlorophyll fluorescence parameters(F_(m), F_(v)/F_(m) and F_(v)/F_(o)) of Monto were higher than those of Veriveria nermorlis, and the translocation factor, bioconcentration factor and the cadmium accumulation in the leaves and roots of Monto were lower than Veriveria nermorlis.(2) It was also found that more than 95% of accumulated Cd existed in the cell wall and soluble components of the leaves and roots of both ecotypes. The proportions of Cd in the cell wall of leaves and roots of Monto, and leaves of Veriveria nermorlis were increased with the rise of Cd concentration, and the proportions of Cd in soluble fraction were decreased gradually, while those of Veriveria nermorlis roots displayed the opposite trend. And the proportions of Cd in the cell wall of leaves of Monto were higher than Veriveria nermorlis.(3) Analysis of chemical forms of Cd distribution showed that NaCl-extracted Cd had the highest ratio in leaves, while ethanol-and NaCl-extracted Cd were dominant in roots of Monto and Veriveria nermorlis. Further, a higher proportion of ethanol-extracted Cd and a lower proportion of NaCl-extracted Cd were observed in the roots of Monto. This work can suggest that Monto was more tolerant to cadmium stress comparing to Veriveria nermorlis, which may be mainly associated with the lower Cd accumulation, bioconcentration fa

关 键 词：香根草 生态型 镉胁迫 叶绿素荧光 亚细胞分布 化学形态 

分 类 号：Q945.79[生物学—植物学] Q942.6