外源硅对镉胁迫下玉米生理参数及根系构型分级的影响  

Effects of exogenous silicon application on physiological parameters,root architecture and diameter distribution of maize under cadmium stress

作　　者：姜瑛[1] 魏畅 焦秋娟 申凤敏 李鸽子 张雪海 杨芳 柳海涛 JIANG Ying;WEI Chang;JIAO Qiu-juan;SHEN Feng-min;LI Ge-zi;ZHANG Xue-hai;YANG Fang;LIU Hai-tao(College of Resources and Environmental Science,Henan Agricultural University,Zhengzhou 450002,China;College of Agronomy,Henan Agricultural University,State Key Laboratory of Wheat and Maize Crop Science,Zhengzhou 450002,China;College of Resources and Environmental Science,Jilin Agricultural University,Changchun 130118,China)

机构地区：[1]河南农业大学资源与环境学院,河南郑州450002 [2]河南农业大学农学院,省部共建小麦玉米作物学国家重点实验室,河南郑州450002 [3]吉林农业大学资源与环境学院,吉林长春130118

出　　处：《草业学报》2022年第9期139-154,共16页Acta Prataculturae Sinica

基　　金：国家自然科学基金青年基金(31901090);河南省科技攻关项目(212102110393;202102110012);山东农业大学作物生物学国家重点实验室开放课题项目基金(2018KF05);河南省留学人员科研择优资助项目(30602340);河南农业大学青年英才专项基金项目(30500671)资助。

摘　　要：为探究镉(Cd)胁迫条件下,施硅(Si)对玉米幼苗生长以及根系构型分级的影响,寻求可缓解Cd对玉米毒害的有效途径,本研究采用水培试验,在Cd胁迫条件下施加不同浓度Si,测定玉米的Cd浓度及含量、生长相关指标、光合指标、根系构型,并将根系构型按根系直径进行分级比较其变化特征。结果表明,Cd胁迫条件下玉米幼苗的生长发育受到抑制,叶绿素含量上升,光合参数显著降低,总根长、根表面积、根体积、根尖数和分枝数,包括Ⅰ~Ⅲ级径级区间的根长,和Ⅰ~Ⅱ级径级区间的根表面积以及根体积显著下降。施加不同浓度Si后,玉米幼苗整株Cd含量降低了12.65%~88.07%,Cd毒害在不同程度上得到缓解,表现为株高、主根长、生物量和耐受指数的提高;总叶绿素含量在Si浓度为0.25 mmol·L^(-1)时提高了11.76%,Cd胁迫下气孔导度、胞间CO_(2)浓度和蒸腾速率分别在Si浓度为1.00 mmol·L^(-1)时显著提高;总根长、分枝数、Ⅰ级径级区间的根长、根表面积和根体积在Si浓度为1.00 mmol·L^(-1)时达到最大,当Si浓度为1.50 mmol·L^(-1)时,根表面积和根体积达到峰值。相关性分析表明Ⅰ~Ⅲ级径级区间内的总根长和根表面积,以及Ⅰ~Ⅱ级径级区间的根体积与Cd转运系数呈显著负相关;生长耐受性综合评价表明,总体上1.00 mmol·L^(-1)外源Si缓解50μmol·L^(-1)玉米Cd毒害的效果最佳。结果表明,施Si可通过降低玉米幼苗根系对Cd的吸收、积累和转运,减少地上部的Cd浓度及积累,从而减小Cd对光合系统的影响,提高玉米幼苗生物量,并进一步促进光合产物向地下部的分配,减轻Cd对根系构型的影响,提高玉米耐Cd能力,缓解Cd对玉米的毒害作用。The aim of this study was to explore the effect of silicon(Si)on the root architecture,root diameter distribution and seedling growth of maize(Zea mays)under cadmium(Cd)stress,and to find an effective way to alleviate the toxicity of Cd on maize seedlings.The experiment had eight treatments:Control(no Cd,no Si),Cd only and six different concentrations of applied Si(0.25,0.50,1.00,1.50,2.00 and 4.00 mmol·L^(-1) Si)with hydroponic cultivation to test the Cd concentration and content of maize,growth-related indicators,photosynthetic indicators,and root architecture and diameter.The root architecture was assessed by classifying roots into four diameter classes(Ⅰ,<0.5 mm;Ⅱ,0.5-1.0 mm;Ⅲ,1.0-1.5 mm;Ⅳ,<1.5 mm)and the plant characteristics of the various treatments were compared.It was found that Cd stress inhibited the growth and development of maize seedlings,the chlorophyll content increased,and the photosynthetic parameters were significantly decreased.Total root length,root surface area,root volume,number of root tips and root forks,including root length of diameter classesⅠ-Ⅲ,root surface area and root volume of the diameter classes ofⅠ-Ⅱwere decreased significantly.After applying different concentrations of Si,the Cd accumulation of plants was reduced by 12.65%-88.07%,and the Cd toxicity was alleviated to varying extents.Alleviation of Cd toxicity manifested as increase in plant height,main root length,biomass and tolerance index.In plants with the 0.25 mmol·L^(-1) concentration of Si applied,the total chlorophyll content was increased by 11.76%.Under Cd stress,stomatal conductance,intercellular CO_(2) concentration and transpiration rate were significantly increased with the applied Si concentration of 1.00 mmol·L^(-1).The total root length,number of root forks,and the root length,root surface area and root volume in the ClassⅠdiameter range were maximized at the Si concentration of 1.00 mmol·L^(-1);The root surface area and root volume peaked at the Si concentration of 1.50 mmol·L^(-1).Corr

关 键 词：玉米 镉 硅 根系构型 根系分级 

分 类 号：X173[环境科学与工程—环境科学] S513[农业科学—作物学]