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

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