Abstract: To explore the effects of chalcogens（sulfur，selenium and tellurium） on cadmium（Cd）absorption and transport of wheat seedlings，the effects of different types［Na₂SO₄（sulfate，SVI），Na₂SO₃（sulfite，SIV），Na₂SeO₄（selenate，SeVI），Na₂SeO₃（selenite，SeIV），and Na₂TeO₃（thioselenite，TeIV）］，addition amounts（600，1 200，2 400 μmol/L for SVI and SIV，and 5，15，30 μmol/L for SeVI，SeIV，and TeIV），treatment durations（2，6，12，24，48，96，168 h）and pretreatment durations（0，24，72，168 h）of chalcogens on Cd absorption kinetics，content and translocation factor of wheat seedlings were studied.The results showed that compared with Cd treatment alone（control），SVI，SeVI and SeIV had a relatively smaller impact on the Cd absorption rate and the maximum absorption rate（V_max）. However，SIV and TeIV had a greater impact on the Cd absorption rate and V_max，among which the 1 200 μmol/L SIV and 15 μmol/L TeIV treatments had the higher V_max，with 88.1% and 54.4% higher than the control，respectively.The 600 μmol/L SIV treatment had the highest Cd Michaelis constant（K_m），which was 39.7% higher than the control；while K_m of SeIV and TeIV treatments decreased. The addition of chalcogens could significantly reduce Cd contents of root and shoot.Among them，SeIV had the greatest impact on Cd content of root，Cd contents of roots of 5，15，and 30 μmol/L SeIV treatments decreased by 56.1%，61.2%，and 61.5% compared with the control，respectively. Compared with the control，the Cd translocation factor of 1 200 and 2 400 μmol/L SVI treatments significantly decreased by 2.4% and 14.0%，respectively.Chalcogens promoted Cd absorption of root when the treatment duration was ≤24 h，inhibited Cd absorption of root when the treatment duration was ≥48 h，and reduced Cd content of root by 34.9%（SVI）to 49.1%（SeIV）compared with the control at 168 hours. Chalcogens significantly decreased Cd content of shoot when the treatment duration was ≥96 h，the reducing effect of SeVI and TeIV with the treatment duration ≥48 h on the Cd content of shoot was more significant. Compared with the control，the 168 h treatment of SeVI and TeIV reduced Cd content of shoot by 48.4% and 50.7%，respectively.When the duration of chalcogen treatment was ≤96 h，the Cd translocation factor was significantly higher than or not significantly different from the control. When the duration of chalcogen treatment was 168 h，the Cd
translocation factor of SeVI and TeIV treatments significantly decreased compared with the control.Chalcogen pretreatment could reduce Cd contents of root and shoot. With the pretreatment time extension，the Cd contents of root and shoot under SIV treatment，the Cd content of shoot and Cd translocation factor under SVI treatment，and Cd translocation factor under TeIV treatment all showed decrease trend.At 168 h of pretreatment，Cd translocation factors of SVI and TeIV decreased by of 33.9% and 7.1% compared with the control，respectively. In conclusion，the effects of chalcogens on the Cd absorption and transport are influenced by type，addition amount，treatment duration and pretreatment duration.The 1 200，2 400 μmol/L SVI and 15 μmol/L TeIV reduce Cd translocation factor through enhancing the Cd fixation in roots. Treatment with chalcogens for more than 48 h obviously decreases Cd content of root，and more than 96 h significantly decreases Cd content of shoot. Chalcogens pretreatment can reduce Cd contents of root and shoot，and 168 h of SVI pretreatment has the lowest Cd translocation factor，which is 33.9% lower than the control.

Key words: Wheat, Cadmium stress, Chalcogens, Application amount, Treatment duration, Pretreatment duration, Absorption, Transport

摘要： 为探讨硫族元素（硫、硒和碲）对小麦幼苗镉（Cd）吸收转运的影响，研究硫族元素种类［Na₂SO₄（硫酸盐，SVI）、Na₂SO₃（亚硫酸盐，SIV）、Na₂SeO₄（硒酸盐，SeVI）、Na₂SeO₃（亚硒酸盐，SeIV）和Na₂TeO₃（亚碲酸盐，TeIV）］、添加量（SVI 和SIV 浓度为600、1 200、2 400 μmol/L，SeVI、SeIV 和TeIV 浓度为5、15、30 μmol/L）、处理时长（2、6、12、24、48、96、168 h）和预处理时长（0、24、72、168 h）对小麦幼苗Cd吸收动力学、含量和转运系数的影响。结果表明，与单独Cd处理（对照）相比，SVI、SeVI和SeIV对小麦幼苗根系Cd 吸收速率和最大吸收速率（V_max）的影响较小，而SIV 和TeIV 对Cd 吸收速率和V_max 影响较大，1 200 μmol/L SIV和15 μmol/L TeIV处理V_max较大，分别比对照提高88.1%和54.4%；600 μmol/L SIV处理米氏常数（K_m）最高，较对照提高39.7%，而SeIV和TeIV处理K_m降低。添加硫族元素能明显降低小麦根系和地上部Cd含量，其中，SeIV对根系Cd含量的影响最大，5、15、30 μmol/L SeIV分别使根系Cd含量比对照显著降低56.1%、61.2%、61.5%；1 200、2 400 μmol/L SVI使Cd转运系数较对照显著降低，分别降低2.4%、14.0%。硫族元素处理24 h内促进根系Cd吸收，处理≥48 h抑制根系Cd吸收，处理168 h时可使根系Cd含量较对照降低34.9%（SVI）~49.1%（SeIV）。硫族元素处理时长≥96 h显著降低地上部Cd含量，其中，SeVI和TeIV处理时长≥48 h降低地上部Cd含量的效果较显著，处理168 h时分别使地上部Cd含量较对照降低48.4%和50.7%。硫族元素处理时长≤96 h时Cd转运系数显著高于对照或与对照差异不显著；处理时长为168 h时，SeVI和TeIV使Cd转运系数显著低于对照。硫族元素预处理可降低小麦根系和地上部Cd含量。随预处理时长增加，SIV处理根系和地上部Cd含量、SVI处理地上部Cd含量和转运系数、TeIV处理Cd转运系数均呈降低趋势；预处理168 h时，SVI和TeIV分别使Cd转运系数较对照降低33.9%和7.1%。综上，硫族元素的种类、添加量、处理时长和预处理时长都会影响Cd的吸收和转运；1 200、2 400 μmol/L SVI和15 μmol/L TeIV通过增强根部对Cd的固定降低Cd转运系数；硫族元素处理时长≥48 h明显降低根部Cd含量，处理时长≥96 h显著降低地上部Cd含量；硫族元素预处理可降低小麦根系和地上部Cd含量，SVI预处理168 h时Cd转运系数最低，较对照降低33.9%。

关键词: 小麦, 镉胁迫, 硫族元素, 添加量, 处理时长, 预处理时长, 吸收, 转运