基于细胞壁吸附固定特性的小飞蓬耐Cd机制研究
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摘要
为探究小飞蓬根、叶细胞壁在Cd吸收过程中发挥的作用,以小飞蓬为供试植物,扫描电镜(SEM)观察Cd在小飞蓬组织中的分布及受损情况,通过细胞壁化学改性,利用吸附动力学和傅里叶红外光谱技术(FTIR)对小飞蓬根、叶细胞壁的Cd吸附固定特性进行了研究。扫描电镜结果显示,Cd胁迫下小飞蓬根、叶组织结构排列不规则,并出现晶体堵塞导管的现象,皮层组织是小飞蓬吸附固定Cd的重要部位;经酯化改性、氨基甲基化改性和果胶酶改性后,吸附动力学试验表明根细胞壁对Cd的累积吸附量分别相对降低了49.1%、38.5%和26.1%,叶细胞壁分别相对降低了39.47%、20.14%和30.23%。根细胞壁上的羧基和氨基在Cd吸附中的贡献作用较大,而叶细胞壁上的羧基和果胶在Cd吸附中的作用较明显。利用FTIR表征了小飞蓬根、叶细胞壁上Cd吸附位点的官能团信息后表明,在小飞蓬根、叶细胞壁吸附Cd的过程中,羟基、羧基和氨基是Cd的主要结合位点。其中,果胶为Cd的结合提供羟基官能团,纤维素和半纤维素为Cd的结合提供羧基官能团,而细胞壁蛋白提供了氨基官能团等结合位点。由此可见,细胞壁各组分中的羟基、羧基和氨基提供Cd结合位点,使细胞壁对Cd具有较高的吸附固定能力,是小飞蓬耐Cd的一种重要机制。
We examined the distribution and damage incurred by the tissues of Conyza canadensis due to Cd stress using scanning electron microscopy(SEM). The adsorption and fixation characteristics of Cd in the root and leaf cell wall were studied by chemical modification,adsorption kinetics, and Fourier transform infrared spectroscopy(FTIR). The results of SEM showed that under Cd stress, the structure of root and leaf tissues was irregularly arranged, and crystals blocked the vessels. The cortical tissue of C. canadensis was an important site for the adsorption and fixation of Cd. The adsorption kinetics test showed that the cumulative adsorptive capacity of the root cell walls for Cd was reduced by 49.1%, 38.5%, and 26.1% after esterification, aminomethylation, and pectinase modification, respectively. That of the leaf cell walls was also reduced, by 39.47%, 20.14%, and 30.23%, respectively. Carboxyl and amino groups in the root cell wall contributed greatly to Cd adsorption, while carboxyl and pectin in the leaf cell wall played a significant role. The functional group information of Cd adsorption sites on the root and leaf cell wall was characterized by FTIR, and the results showed that hydroxyl, carboxyl, and amino groups were the main binding sites. During this process, pectin provided the hydroxyl functional groups for the binding of Cd, cellulose and hemi cellulose provided the carboxyl functional groups, and cell wall proteins provided the amino functional groups and other binding sites. It can be concluded that hydroxyl, carboxyl, and amino groups are the main binding sites of Cd, which results in the cell wall showing a higher adsorption and fixation ability for Cd, and is an important mechanism of Cd tolerance in C. canadensis.
We examined the distribution and damage incurred by the tissues of Conyza canadensis due to Cd stress using scanning electron microscopy(SEM). The adsorption and fixation characteristics of Cd in the root and leaf cell wall were studied by chemical modification,adsorption kinetics, and Fourier transform infrared spectroscopy(FTIR). The results of SEM showed that under Cd stress, the structure of root and leaf tissues was irregularly arranged, and crystals blocked the vessels. The cortical tissue of C. canadensis was an important site for the adsorption and fixation of Cd. The adsorption kinetics test showed that the cumulative adsorptive capacity of the root cell walls for Cd was reduced by 49.1%, 38.5%, and 26.1% after esterification, aminomethylation, and pectinase modification, respectively. That of the leaf cell walls was also reduced, by 39.47%, 20.14%, and 30.23%, respectively. Carboxyl and amino groups in the root cell wall contributed greatly to Cd adsorption, while carboxyl and pectin in the leaf cell wall played a significant role. The functional group information of Cd adsorption sites on the root and leaf cell wall was characterized by FTIR, and the results showed that hydroxyl, carboxyl, and amino groups were the main binding sites. During this process, pectin provided the hydroxyl functional groups for the binding of Cd, cellulose and hemi cellulose provided the carboxyl functional groups, and cell wall proteins provided the amino functional groups and other binding sites. It can be concluded that hydroxyl, carboxyl, and amino groups are the main binding sites of Cd, which results in the cell wall showing a higher adsorption and fixation ability for Cd, and is an important mechanism of Cd tolerance in C. canadensis.
引文
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[10]罗洁文.类芦对重金属的吸收、富集机制及修复效果研究[D].福州:福建农林大学,2017.LUO Jie-wen.Absorption and accumulation mechanism of heavy metals and the effect of phytoremeduation by Neyraudia reynaudiana[D].Fuzhou:Fujian Agriculture and Forestry University,2017.
[11]朱宇恩,赵烨,徐东昱,等.旱柳(Salix matsudana Koidz)体内Cu迁移特征的水培模拟研究[J].环境科学学报,2011,31(12):2740-2747.ZHU Yu-en,ZHAO Ye,XU Dong-yu,et al.Investigation on the characteristics of copper migration in different tissues of Salix matsudana Koidz based on hydroponic experiment[J].Acta Scientiae Circumstantiae,2011,31(12):2740-2747.
[12]黄玫英,罗洁文,黄彩凤,等.Pb在类芦组织和亚细胞中的分布规律和毒害效应[J].农业环境科学学报,2016,35(11):2077-2085.HUANG Mei-ying,LUO Jie-wen,HUANG Cai-feng,et al.The distribution and toxic effects of Pb at the levels of the tissues and sub-cellular in Neyraudia reynaudiana[J].Journal of Agro-Environment Science,2016,35(11):2077-2085.
[13]武贝.海州香薷Cu耐性与积累机制研究[D].杭州:浙江大学,2009.WU Bei.Study of mechanisms for Cu tolerance and accumulation in Elsholtzia splendens[D].Hangzhou:Zhejiang University,2009.
[14]徐劼,保积庆.芹菜根细胞壁对镉的吸附固定机制及其FTIR表征研究[J].环境科学学报,2015,35(8):2605-2612.XU Jie,BAO Ji-qing.Adsorption and fixation mechanism of cadmium on celery(Apium graveolens L.)root cell wall and the analysis of FT-IR spectra[J].Acta Scientiae Circumstantiae,2015,35(8):2605-2612.
[15]Peterson C A,Enstone D E,Taylor J H.Pine root structure and its potential significance for root function[J].Plant and Soil,1999,217:205-213.
[16]Chen Z,Zhao Y,Fan L,et al.Cadmium(Cd)localization in tissues of cotton(Gossypium hirsutum L.),and its phytoremediation potential for Cd-contaminated soils[J].Bulletin of Environmental Contamination&Toxicology,2015,95(6):784-789.
[17]Liu D,Kottke I,Adam D.Localization of cadmium in the root cells of Allium cepa by energy dispersive x-ray analysis[J].Biol Plant,2007,51(2):363-366.
[18]张旭红,高艳玲,林爱军,等.植物根系细胞壁在提高植物抵抗金属离子毒性中的作用[J].生态毒理学报,2008,3(1):9-14.ZHANG Xu-hong,GAO Yan-ling,LIN Ai-jun,et al.A review on the effect of cell wall on the resistance of plants to metal stress[J].Asian Journal of Ecotoxicology,2008,3(1):9-14.
[19]Clemens S.Molecular mechanisms of plant metal tolerance and homeostasis[J].Planta,2001,212(4):475-486.
[20]Wgt W,Knox J P,Mikkelsen J D.Pectin:New insights into an old polymer are starting to gel[J].Trends in Food Science&Technology,9903852006,17(3):97-104.
[21]Douchiche O,Driouich A,Morvan C.Spatial regulation of cell-wall structure in response to heavy metal stress:Cadmium-induced alteration of the methyl-esterification pattern of homogalacturonans[J].Annals of Botany,2010,105(3):481-491.
[22]Krzes?owska M,Lenartowska M,Mellerowicz E J,et al.Pectinous cell wall thickenings formation:A response of moss protonemata cells to lead[J].Environmental&Experimental Botany,2009,65(1):119-131.
[23]王梦,段德超,徐辰,等.茶树根细胞壁不同组分对铅的吸附性能及其功能团的傅里叶红外光谱学研究[J].生态学报,2015,35(6):1743-1751.WANG Meng,DUAN De-chao,XU Chen,et al.Adsorption ability of cell wall(CW)components in roots of Tea Plant(Camellia sinensis L.)to Pb and FTIR spectra of their functional groups[J].Acta Ecologica Sinica,2015,35(6):1743-1751.
[24]Gardea-Torresdey J L,Tiemann K J,Parsons J G,et al.XAS investigations into the mechanism(s)of Au(Ⅲ)binding and reduction by alfalfa biomass[J].Microchemical Journal,2002,71(2):193-204.
[25]Kulczycki E,Ferris F G,Fortin D.Impact of cell wall structure on the behavior of bacterial cells as sorbents of cadmium and lead[J].Geomicrobiology Journal,2002,19(6):553-565.
[26]Krzes?owska M.The cell wall in plant cell response to trace metals:Polysaccharide remodeling and its role in defense strategy[J].Acta Physiologiae Plantarum,2011,33(1):35-51.
[27]张晓斌,刘鹏,李丹婷,等.铬诱导植物根细胞壁化学成分变化的FTIR表征[J].光谱学与光谱分析,2008,28(5):1067-1070.ZHANG Xiao-bin,LIU Peng,LI Dan-ting,et,al.FTIR spectroscopic characterization of chromium-induced changes in root cell wall of plants[J].Spectroscopy and Spectral Analysis,2008,28(5):1067-1070.
[28]Renault H,El A A,Berger A,et al.γ-aminobutyric acid transaminase deficiency impairs central carbon metabolism and leads to cell wall defects during salt stress in Arabidopsis roots[J].Plant Cell&Environment,2013,36(5):1009-1018.
[29]Wei Z L,Dong L,Tian Z H.Fourier transform infrared spectometry study on early stage of cadmium stress in clover leaves[J].Pakistan Journal Botaty,2009,41(4):1743-1750.
[30]顾艳红,刘鹏,蔡琪敏,等.FTIR结合生理特性研究镉胁迫对果灰藓的影响[J].光谱学与光谱分析,2009,29(3):620-623.GU Yan-hong,LIU Peng,CAI Qi-min,et al.Effects of Cd stress on FTIR spectra and physiological traits of Hhypnum fertile Sendtn[J].Spectroscopy and Spectral Analysis,2009,29(3):620-623.
[31]王成,蒋泽平,李文青,等.FTIR-NIR研究镉胁迫对构树试管幼苗生长的影响与机理[J].农业环境科学学报,2014,33(4):673-679.WANG Cheng,JIANG Ze-ping,LI Wen-qing,et al.FTIR-NIR spectrum study on response and mechanism of Broussonetia papyrifera sprout under cadmium stresses[J].Journal of Agro-Environment Science,2014,33(4):673-679.
[2]欧丽,刘足根,方红亚,等.定南县岿美山钨矿尾砂库区天然生长植物及其富集Cd特性研究[J].安徽农业科学,2010,38(3):1618-1620.OU Li,LIU Zu-gen,FANG Hong-ya,et al.Study on natural plants growth and their enrichment characteristics of Cd in Kuimei Tungsten mine area of Dingnan County[J].Journal of Anhui Agricultural Sciences,2010,38(3):1618-1620.
[3]Wei S,Zhou Q,Saha U K,et al.Identification of a Cd accumulator Conyza canadensis[J].Journal of Hazardous Materials,2009,163(1):32-35.
[4]杨刚,伍钧,唐亚,等.铅锌矿业废弃地草本植物重金属耐性研究[J].四川环境,2006,25(4):18-21.YANG Gang,WU Jun,TANG Ya,et al.Tolerance to heavy metals of some herbages in mining wasteland[J].Sichuan Environment,2006,25(4):18-21.
[5]徐劼,保积庆,于明革,等.茶树根细胞壁对铅的吸附作用[J].应用生态学报,2014,25(2):427-432.XU Jie,BAO Ji-qing,YU Ming-ge,et al.Lead adsorption by the root cell wall of tea plant[J].Chinese Journal of Applied Ecology,2014,25(2):427-432.
[6]孙婕妤,刘艳秋,李佰林,等.植物对镉的耐性机制以及对镉污染土壤修复的研究进展[J].江苏农业科学,2018,46(7):12-19.SUN Jie-yu,LIU Yan-qiu,LI Bai-lin,et al.Research progress on mechanism of plant tolerance to cadmium and remediation of cadmium contaminated soil[J].Jiangsu Agricultural Sciences,2018,46(7):12-19.
[7]Xiong J,An L,Lu H,et al.Exogenous nitric oxide enhances cadmium tolerance of rice by increasing pectin and hemicelluloses contents in root cell wall[J].Planta,2009,230(4):755-765.
[8]Je V D M,Schat H,Moerland P D,et al.Expression differences for genes involved in lignin,glutathione and sulphate metabolism in response to cadmium in Arabidopsis thaliana and the related Zn/Cd-hyperaccumulator Thlaspi caerulescens[J].Plant Cell&Environment,2010,31(3):301-324.
[9]Zhou C,Zhang K,Lin J,et al.Physiological responses and tolerance mechanisms to cadmium in Conyza canadensis[J].International Journal of Phytoremediation,2015,17(3):280-289.
[10]罗洁文.类芦对重金属的吸收、富集机制及修复效果研究[D].福州:福建农林大学,2017.LUO Jie-wen.Absorption and accumulation mechanism of heavy metals and the effect of phytoremeduation by Neyraudia reynaudiana[D].Fuzhou:Fujian Agriculture and Forestry University,2017.
[11]朱宇恩,赵烨,徐东昱,等.旱柳(Salix matsudana Koidz)体内Cu迁移特征的水培模拟研究[J].环境科学学报,2011,31(12):2740-2747.ZHU Yu-en,ZHAO Ye,XU Dong-yu,et al.Investigation on the characteristics of copper migration in different tissues of Salix matsudana Koidz based on hydroponic experiment[J].Acta Scientiae Circumstantiae,2011,31(12):2740-2747.
[12]黄玫英,罗洁文,黄彩凤,等.Pb在类芦组织和亚细胞中的分布规律和毒害效应[J].农业环境科学学报,2016,35(11):2077-2085.HUANG Mei-ying,LUO Jie-wen,HUANG Cai-feng,et al.The distribution and toxic effects of Pb at the levels of the tissues and sub-cellular in Neyraudia reynaudiana[J].Journal of Agro-Environment Science,2016,35(11):2077-2085.
[13]武贝.海州香薷Cu耐性与积累机制研究[D].杭州:浙江大学,2009.WU Bei.Study of mechanisms for Cu tolerance and accumulation in Elsholtzia splendens[D].Hangzhou:Zhejiang University,2009.
[14]徐劼,保积庆.芹菜根细胞壁对镉的吸附固定机制及其FTIR表征研究[J].环境科学学报,2015,35(8):2605-2612.XU Jie,BAO Ji-qing.Adsorption and fixation mechanism of cadmium on celery(Apium graveolens L.)root cell wall and the analysis of FT-IR spectra[J].Acta Scientiae Circumstantiae,2015,35(8):2605-2612.
[15]Peterson C A,Enstone D E,Taylor J H.Pine root structure and its potential significance for root function[J].Plant and Soil,1999,217:205-213.
[16]Chen Z,Zhao Y,Fan L,et al.Cadmium(Cd)localization in tissues of cotton(Gossypium hirsutum L.),and its phytoremediation potential for Cd-contaminated soils[J].Bulletin of Environmental Contamination&Toxicology,2015,95(6):784-789.
[17]Liu D,Kottke I,Adam D.Localization of cadmium in the root cells of Allium cepa by energy dispersive x-ray analysis[J].Biol Plant,2007,51(2):363-366.
[18]张旭红,高艳玲,林爱军,等.植物根系细胞壁在提高植物抵抗金属离子毒性中的作用[J].生态毒理学报,2008,3(1):9-14.ZHANG Xu-hong,GAO Yan-ling,LIN Ai-jun,et al.A review on the effect of cell wall on the resistance of plants to metal stress[J].Asian Journal of Ecotoxicology,2008,3(1):9-14.
[19]Clemens S.Molecular mechanisms of plant metal tolerance and homeostasis[J].Planta,2001,212(4):475-486.
[20]Wgt W,Knox J P,Mikkelsen J D.Pectin:New insights into an old polymer are starting to gel[J].Trends in Food Science&Technology,9903852006,17(3):97-104.
[21]Douchiche O,Driouich A,Morvan C.Spatial regulation of cell-wall structure in response to heavy metal stress:Cadmium-induced alteration of the methyl-esterification pattern of homogalacturonans[J].Annals of Botany,2010,105(3):481-491.
[22]Krzes?owska M,Lenartowska M,Mellerowicz E J,et al.Pectinous cell wall thickenings formation:A response of moss protonemata cells to lead[J].Environmental&Experimental Botany,2009,65(1):119-131.
[23]王梦,段德超,徐辰,等.茶树根细胞壁不同组分对铅的吸附性能及其功能团的傅里叶红外光谱学研究[J].生态学报,2015,35(6):1743-1751.WANG Meng,DUAN De-chao,XU Chen,et al.Adsorption ability of cell wall(CW)components in roots of Tea Plant(Camellia sinensis L.)to Pb and FTIR spectra of their functional groups[J].Acta Ecologica Sinica,2015,35(6):1743-1751.
[24]Gardea-Torresdey J L,Tiemann K J,Parsons J G,et al.XAS investigations into the mechanism(s)of Au(Ⅲ)binding and reduction by alfalfa biomass[J].Microchemical Journal,2002,71(2):193-204.
[25]Kulczycki E,Ferris F G,Fortin D.Impact of cell wall structure on the behavior of bacterial cells as sorbents of cadmium and lead[J].Geomicrobiology Journal,2002,19(6):553-565.
[26]Krzes?owska M.The cell wall in plant cell response to trace metals:Polysaccharide remodeling and its role in defense strategy[J].Acta Physiologiae Plantarum,2011,33(1):35-51.
[27]张晓斌,刘鹏,李丹婷,等.铬诱导植物根细胞壁化学成分变化的FTIR表征[J].光谱学与光谱分析,2008,28(5):1067-1070.ZHANG Xiao-bin,LIU Peng,LI Dan-ting,et,al.FTIR spectroscopic characterization of chromium-induced changes in root cell wall of plants[J].Spectroscopy and Spectral Analysis,2008,28(5):1067-1070.
[28]Renault H,El A A,Berger A,et al.γ-aminobutyric acid transaminase deficiency impairs central carbon metabolism and leads to cell wall defects during salt stress in Arabidopsis roots[J].Plant Cell&Environment,2013,36(5):1009-1018.
[29]Wei Z L,Dong L,Tian Z H.Fourier transform infrared spectometry study on early stage of cadmium stress in clover leaves[J].Pakistan Journal Botaty,2009,41(4):1743-1750.
[30]顾艳红,刘鹏,蔡琪敏,等.FTIR结合生理特性研究镉胁迫对果灰藓的影响[J].光谱学与光谱分析,2009,29(3):620-623.GU Yan-hong,LIU Peng,CAI Qi-min,et al.Effects of Cd stress on FTIR spectra and physiological traits of Hhypnum fertile Sendtn[J].Spectroscopy and Spectral Analysis,2009,29(3):620-623.
[31]王成,蒋泽平,李文青,等.FTIR-NIR研究镉胁迫对构树试管幼苗生长的影响与机理[J].农业环境科学学报,2014,33(4):673-679.WANG Cheng,JIANG Ze-ping,LI Wen-qing,et al.FTIR-NIR spectrum study on response and mechanism of Broussonetia papyrifera sprout under cadmium stresses[J].Journal of Agro-Environment Science,2014,33(4):673-679.
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