镉胁迫对4种基因型大豆生长和体内元素分布的影响

Effects of cadmium stress on plant growth and element distribution of four soybean genotypes

【目的】分析不同基因型大豆的镉(Cd)敏感性差异,筛选耐Cd基因型应用于大豆育种。【方法】选用‘巴西10号’、‘本地2号’、‘桂夏豆2号’、‘华夏3号’4种基因型大豆,设置不同Cd浓度处理,测定主根长、生物量、总根长、根表面积、Cd浓度以及不同营养元素浓度等指标。【结果】在11 mg/kg Cd处理下,‘华夏3号’主根长与对照相比没有明显变化,其他基因型主根生长均受到明显抑制;在高于46 mg/kg Cd处理下,4种基因型大豆主根生长均受到严重抑制。Cd处理降低了大豆生物量,‘巴西10号’和‘本地2号’受到的Cd毒害较严重;‘桂夏豆2号’和‘华夏3号’在10、20 mg/kg Cd处理下生物量显著高于‘巴西10号’和‘本地2号’。4种基因型大豆的根部Cd浓度远高于地上部,在10 mg/kg Cd处理下,‘本地2号’的地上部Cd浓度显著高于‘桂夏豆2号’和‘华夏3号’,表明耐Cd的‘桂夏豆2号’和‘华夏3号’有较少的Cd转移到地上部。Cd处理后4种基因型大豆的根系生长均受到明显抑制,相比于其他3种大豆基因型,‘华夏3号’的总根长和根表面积受到的抑制程度最小。在不同Cd浓度处理中4种基因型大豆各营养元素的浓度有显著差异。【结论】4种基因型大豆的耐Cd能力存在显著差异,‘巴西10号’和‘本地2号’是Cd敏感基因型,‘桂夏豆2号’和‘华夏3号’是耐Cd基因型。耐Cd能力的差异可能与Cd处理下大豆根系生长和体内元素分布有关。

【Objective】To analyze cadmium(Cd)sensitivity differences of different soybean genotypes,and screen Cd-tolerant genotypes for soybean breeding.【Method】Different Cd concentrations were set,four soybean genotypes of‘Baxi No.10’,‘Bendi No.2’,‘Guixiadou No.2’and‘Huaxia No.3’were selected as test materials.The taproot length,biomass,total root length,root surface area,Cd concentration and nutrient element concentrations were determined.【Result】Under 11 mg/kg Cd treatment,the taproot length of‘Huaxia No.3’did not obviously change compared with the control while the taproot growths of other three soybean genotypes were distinctly inhibited.The taproot growths of four soybean genotypes were severely inhibited when Cd concentrations were higher than 46 mg/kg.Cd treatment reduced soybean biomass.‘Baxi No.10’and‘Bendi No.2’were more severely Cd-toxic.‘Guixiadou No.2’and‘Huaxia No.3’showed significantly higher biomasses than‘Baxi No.10’and‘Bendi No.2’under 10 and 20 mg/kg Cd stress treatments.The Cd concentrations in roots of four soybean genotypes were far higher than those in shoots.In 10 mg/kg Cd treatment,Cd concentration in the shoot of‘Bendi No.2’was significantly higher than those in shoots of‘Guixiadou No.2’and‘Huaxia No.3’,indicating that Cd-resistant‘Guixiadou No.2’and‘Huaxia No.3’transfered less Cd from root to shoot.The root growths of four soybean genotypes were significantly inhibited by Cd stress.The total root length and root surface area of‘Huaxia No.3’were less inhibited compared with other three soybean genotypes.There were significant differences among nutrient element concentrations of four soybean genotypes treated by different Cd concentrations.【Conclusion】There are significant genotypic differences of Cd tolerances among four soybean genotypes.‘Baxi No.10’and‘Bendi No.2’are Cd-sensitive genotypes while‘Guixiadou No.2’and‘Huaxia No.3’are Cd-tolerant genotypes.The differences of Cd tolerance may relate to root growth and element distribution in soybean under Cd treatments.