镉安全水稻材料根系细胞壁果胶对镉的响应特征  

The characteristics of cell wall pectin in roots of cadmium-safe rice line in response to cadmium stress

作　　者：杨釜 余海英 黄化刚 李芹 李廷轩 YANG Fu;YU Hai-ying;HUANG Hua-gang;LI Qin;LI Ting-xuan(College of Resource,Sichuan Agricultural University,Chengdu,Sichuan 611130,China;Institute of Agricultural Resources and Environment,Sichuan Academy of Agricultural Sciences,Chengdu,Sichuan 610066,China)

机构地区：[1]四川农业大学资源学院,四川成都611130 [2]四川省农业科学院农业资源与环境研究所,四川成都610066

出　　处：《植物营养与肥料学报》2023年第4期704-711,共8页Journal of Plant Nutrition and Fertilizers

基　　金：四川省区域创新合作项目(22QYCX0104);德阳市“揭榜挂帅”科技计划项目(2021JBJZ016)。

摘　　要：【目的】研究镉(Cd)处理下水稻根系细胞壁果胶对Cd胁迫的响应,进一步深化Cd安全水稻材料根系细胞壁Cd的固持机制。【方法】以Cd安全水稻材料D62B为研究对象,普通材料Luhui17为对照进行水培试验。设4个Cd质量浓度处理:0 mg/L(CK)、0.5 mg/L(Cd0.5)、1.0 mg/L(Cd1)、2.0 mg/L(Cd2)。在水稻分蘖期采集根系样品,分析细胞壁多糖中果胶、半纤维1、半纤维2以及残渣部分的Cd含量,测定果胶糖醛酸含量、果胶酯化度、果胶甲酯酶(PME)活性、根系过氧化氢(H_(2)O_(2))含量以及细胞壁过氧化物酶(POD)活性,进而分析根系细胞壁果胶对Cd的响应特征。【结果】1)Cd胁迫下,D62B和Luhui17根系细胞壁果胶合成增加,根系细胞壁低酯化和高酯化果胶糖醛酸含量均表现为D62B高于Luhui17。Cd处理下D62B根系细胞壁低酯化和高酯化果胶糖醛酸含量较对照分别增加了13.21%~71.82%和22.10%~64.27%,Luhui17分别增加了24.14%~137.86%和13.12%~41.26%。2)Cd1、Cd2处理下D62B和Luhui17根系细胞壁果胶酯化度和PME活性较CK处理均升高;相同Cd处理下D62B根系细胞壁PME活性显著高于Luhui17。3)Cd诱导两类水稻材料根系H_(2)O_(2)积累、影响细胞壁POD活性;Cd胁迫下,D62B根系H_(2)O_(2)含量和细胞壁POD活性较Luhui17更低,PME对果胶去甲酯化作用更强。【结论】Cd胁迫下,Cd安全水稻材料D62B根系细胞壁中低酯化和高酯化果胶合成能力均强于普通材料,且具有更高的PME活性,进而可提供更多的Cd结合位点,表现出较强的Cd结合能力,有利于D62B根系滞留Cd。【Objectives】We compared the properties of cell wall pectin in roots of cadmium(Cd)-safe and common rice line when exposure to Cd stress,to fully understand the mechanism of Cd retention by root of Cdsafe rice line.【Methods】A hydroponic experiment was conducted using a Cd-safe rice line D62B and a common rice line Luhui17 as the comparing material.The Cd concentration of nutrient solution included 0(CK),0.5 mg/L(Cd0.5),1.0 mg/L(Cd1)and 2.0 mg/L(Cd2).At the tillering stage,root samples were collected.The Cd concentrations in cell wall polysaccharides,including pectin,hemicellulose 1,hemicellulose 2 and residue fraction,were determined respectively.Furthermore,the uronic acid concentration of pectin,pectin esterification degree,pectin methyl esterase activity(PME),root hydrogen peroxide(H_(2)O_(2))concentration and cell wall peroxidase(POD)activity were detected,so as to clarify the response characteristics of root cell wall pectin to Cd.【Results】1)Cd treatment promoted the pectin synthesis of root cell wall in both rice lines,and the uronic acid concentrations of low and high esterified pectin in the root cell wall of D62B were higher than those of Luhui17.Compared with CK,the uronic acid concentrations of low esterified and high esterified pectin in the root cell wall of D62B were increased by 13.21%–71.82%,22.10%–64.27%,and those in Luhui17 were increased by 24.14%-137.86%,13.12%-41.26%,respectively,under Cd treatment.2)The pectin esterification degree and PME activity in root cell wall of D62B and Luhui17 were higher than those of CK under Cd1 and Cd2 treatment.The PME activity in root cell wall of D62B was significantly higher than that of Luhui17 under the same Cd stress.3)Cd induced H_(2)O_(2) accumulation and influenced peroxidase activity in the roots of both rice lines.Under Cd stress,the H_(2)O_(2) concentration and peroxidase activity of D62B roots were lower than those of Luhui17,indicating that pectin methyl esterase had stronger demethylation effect on pectin.【Conclusions】When expo

关 键 词：镉安全水稻材料 细胞壁 果胶 去甲酯化作用 

分 类 号：X173[环境科学与工程—环境科学] S511[农业科学—作物学]