镉胁迫对伴矿景天细胞壁多糖果胶组分及其果胶甲酯酶的影响  

Effects of cadmium stress on pectin components and pectin methylesterase of cell wall polysaccharide in Sedum plumbizincicola

作　　者：毕莉艳 李元[1] 李博[1] 李明锐[1] 王吉秀 秦丽[1] BI Liyan;LI Yuan;LI Bo;LI Mingrui;WANG Jixiu;QIN Li(College of Resources and Environment,Yunnan Agricultural University,Kunming 650201,China)

机构地区：[1]云南农业大学资源与环境学院,昆明650201

出　　处：《农业资源与环境学报》2023年第3期636-643,共8页Journal of Agricultural Resources and Environment

基　　金：云南省重点研发计划课题(2019BC001-04);国家自然科学基金项目(31560163,31860112,41761073,41967049)。

摘　　要：为探究细胞壁果胶对Cd胁迫的响应机理,通过盆栽实验研究了不同镉(Cd)浓度(0、25、50、75、100、200 mg·kg^(-1))对伴矿景天细胞壁果胶含量、果胶甲酯酶(PME)活性、细胞壁果胶半乳糖醛酸含量和Cd含量的影响。结果表明,随着Cd处理浓度的增加,伴矿景天地上部和根部细胞壁螯合态果胶、碱性果胶含量均在Cd处理浓度为100 mg·kg^(-1)时最大,且螯合态果胶含量表现为地上部>根部,碱性果胶含量表现为地上部<根部。地上部细胞壁PME活性和半乳糖醛酸含量在Cd处理浓度为25 mg·kg^(-1)时最大,与对照相比显著增加了40.4%和39.2%。Cd胁迫抑制了根部细胞壁PME活性,Cd处理浓度为75 mg·kg^(-1)时,伴矿景天地上部和根部Cd含量最高,与对照相比分别显著增加了58.4倍和70.1倍;螯合态果胶含量和碱性果胶含量与植物Cd含量呈显著正相关;根部的细胞壁果胶半乳糖醛酸含量和螯合态果胶含量呈显著负相关(r=-0.880,P<0.05)。研究发现,伴矿景天通过调整细胞壁果胶半乳糖醛酸含量来改变果胶含量,以增强伴矿景天对Cd的吸收累积。Pot experiments were carried out to study the effects of different cadmium(Cd)concentrations(0,25,50,75,100,200 mg∙kg^(-1))on pectin content,pectin methylesterase enzyme(PME)activity,pectin galacturonic acid content,and Cd accumulation in the cell wall of Sedum plumbizincicola and explore the response mechanism of cell wall pectin to cadmium stress.The results showed that with the increase in Cd concentration,the contents of chelated pectin and alkaline pectin in the shoot and root cell walls of S.plumbizincicola reached a maximum at a concentration of 100 mg∙kg^(-1) Cd,with the content of chelated pectin in shoots overtopping that in the roots.However,alkaline pectin content in the shoots was lower than that in the roots.The PME activity and galacturonic acid content of the shoot cell wall were the highest in the treatment of 25 mg∙kg^(-1) Cd,which were significantly increased by 40.4% and 39.2%,respectively,compared with the control.The PME activity of root cell walls was inhibited under Cd stress.The shoot and root Cd contents reached their maximum values in the treatment of 75 mg∙kg^(-1) Cd,which were 58.4 times and 70.1 times higher than that of the control,respectively.There was a significant positive correlation between chelated pectin content,alkaline pectin content,and Cd content.Furthermore,there was a significant negative correlation between the content of pectin galacturonic acid and chelated pectin in the root cell wall,with a correlation coefficient of-0.880(P<0.05).The pectin content was found to change by regulating the pectin galacturonic acid content in the cell wall of S.plumbizincicola to enhance Cd absorption and accumulation.

关 键 词：伴矿景天 镉 细胞壁 果胶 果胶甲酯酶 半乳糖醛酸 

分 类 号：Q945.78[生物学—植物学] X173[环境科学与工程—环境科学]