CdCl_(2)胁迫对甘蔗幼苗根系细胞壁Cd积累的影响  

Effects of CdCl_(2) Stress on Cadmium Accumulation in Cell Wall of Root System of Sugarcane Seedlings

作　　者：肖京林 覃美 杨曙[1] 易科 黎晓峰[1] 唐新莲[1] 凌桂芝[2] XIAO Jing-lin;QIN Mei;YANG Shu;YI Ke;LI Xiao-feng;TANG Xin-lian;LING Gui-zhi(Guangxi Key Laboratory of Sugarcane Biology/Collaborative Innovation Center of Sugarcane Industry,Ministry of Education/College of Agriculture,Guangxi University,Guangxi Nanning 530004,China;Institute of Agriculture and Animal Husbandry Industry Development,Guangxi University,Guangxi Nanning 530004,China)

机构地区：[1]广西甘蔗生物学重点实验室/教育部蔗糖产业协同创新中心/广西大学农学院,广西南宁530004 [2]广西大学农牧产业发展研究院,广西南宁530004

出　　处：《西南农业学报》2021年第11期2490-2495,共6页Southwest China Journal of Agricultural Sciences

基　　金：国家自然科学基金项目(31660593,31660592);广西科技重大专项(桂科2018-266-Z01);广西自然科学基金项目(2021GXNSFAA070517)。

摘　　要：【目的】探究镉(CdCl_(2))胁迫下甘蔗幼苗根系细胞壁Cd的积累特点及Cd对甘蔗种茎初生根的影响,为在土壤Cd超标区域推广种植甘蔗新品种提供参考依据。【方法】以新选育的中蔗1号(Z1)和中蔗6号(Z6)为试验材料,开展不同浓度(1.0、2.0和5.0μmol/L)CdCl_(2)胁迫水培试验,测定甘蔗幼苗根系的Cd含量和细胞壁中的Cd积累量、果胶和半纤维素含量及甘蔗种茎初生根的相对伸长率和根尖活力等指标,分析根系细胞壁在缓解Cd毒害中的作用并评价2个甘蔗新品种的Cd耐受性。【结果】1.0、2.0和5.0μmol/L CdCl_(2)处理Z1和Z6幼苗根系的Cd含量分别约为其叶片Cd含量的136、124和116倍;甘蔗根系对Cd具有较强的截留能力,其中5.0μmol/L CdCl_(2)处理甘蔗幼苗根系中的Cd有57.50%位于根系细胞壁中,而细胞壁中的Cd有95.00%以上积累在果胶和半纤维素组分中,且随着CdCl_(2)胁迫浓度(1.0、2.0和5.0μmol/L)的提高积累在果胶组分中Cd的比例(18.71%、28.52%和36.28%)显著增加(P<0.05,下同)。同时,甘蔗幼苗根系细胞壁的果胶含量、果胶甲酯酶(PME)活性和去甲酯化果胶含量也随着CdCl_(2)胁迫浓度的提高而增加,使得更多的Cd被细胞壁果胶所吸附固定。CdCl_(2)胁迫下Z1根系和叶片的Cd含量显著高于Z6,而根系相对伸长率和根尖活力与Z6相近,表明Z1对Cd的耐受性强于Z6。【结论】在CdCl_(2)胁迫下,甘蔗幼苗根系的细胞壁是Cd积累的主要部位;CdCl_(2)胁迫致使甘蔗根系细胞壁果胶组分含量增加,PME活性提高,果胶甲酯化程度降低,细胞壁对Cd的结合能力提高,使得更多的Cd被根系细胞壁所吸附积累。【Objective】The accumulation characteristics of Cd in root cell wall of sugarcane seedlings with cadmium(CdCl_(2))stress and the effect of Cd on primary rooting were investigated,so as to provide reference for the promotion of planting new varieties in areas with excessive soil Cd.【Method】Using newly selected Zhongzhe No.1(Z1)and Zhongzhe No.6(Z6)as test materials,hydroponic tests were carried out under different concentrations of CdCl_(2)(1.0,2.0 and 5.0μmol/L)to determine the content of Cd in roots,the accumulation of Cd in cell wall,the contents of pectin and hemifiber,the relative elongation of primary roots and root tip activity.The role of cell wall in alleviating Cd toxicity was analyzed and the Cd tolerance of two new cultivars was evaluated.【Result】Cd content in Z1 and Z6 roots treated with 1.0,2.0 and 5.0μmol/L CdCl_(2)was about 136,124 and 116 times of that in leaves,respectively.The roots had a strong Cd retention ability,and 57.50%of Cd in the 5.0μmol/L CdCl_(2)treatment was located in the root cell wall,while more than 95.00%of Cd in the cell wall was accumulated in pectin and hemicellulose components.Cd accumulation in pectin fractions(18.71%,28.52%and 36.28%)was significantly(P<0.05,the same as below)increased with the increase of CdCl_(2)stress concentration(1.0,2.0 and 5.0μmol/L).The pectin content,PME activity and methyl demethylated pectin content of root cell wall also increased with the increase of CdCl_(2)stress concentration,making more Cd adsorbed and fixed by cell wall pectin.Cd content in roots and leaves of Z1 was significantly higher than that of Z6 under CdCl_(2)stress,while relative root elongation and root tip activity of Z1 were similar to that of Z6,suggesting that Z1 had a stronger tolerance to Cd than Z6.【Conclusion】Under CdCl_(2)stress,the cell wall of sugarcane root was the main part of Cd accumulation.CdCl_(2)stress increased the pectin component content of root cell wall,increased PME activity,decreased the degree of methyl esterification of pectin,and im

关 键 词：甘蔗幼苗 CdCl_(2)胁迫 根系 细胞壁 果胶 半纤维素 Cd积累 

分 类 号：S566.1[农业科学—作物学]