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| Kinetic characteristics and pathways of Cr（Ⅲ）uptake by maize seedling roots |
| Received:August 29, 2022 |
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| KeyWord:maize seedling;chromium;absorption;ion channel;iron |
| Author Name | Affiliation | E-mail | | JU Jing | Key Laboratory of Arable Land Quality Monitoring and Evaluation, Ministry of Agriculture and Rural Affairs, Yangzhou University, Yangzhou 225127, China | | | WANG Xin | Key Laboratory of Arable Land Quality Monitoring and Evaluation, Ministry of Agriculture and Rural Affairs, Yangzhou University, Yangzhou 225127, China | | | CHEN Yonglin | Agricultural Technology Extension Center of Jurong City, Zhenjiang 212499, China | | | SHENG Haijun | Key Laboratory of Arable Land Quality Monitoring and Evaluation, Ministry of Agriculture and Rural Affairs, Yangzhou University, Yangzhou 225127, China | | | WANG Xiaoli | Key Laboratory of Arable Land Quality Monitoring and Evaluation, Ministry of Agriculture and Rural Affairs, Yangzhou University, Yangzhou 225127, China | | | ZHAO Haitao | Key Laboratory of Arable Land Quality Monitoring and Evaluation, Ministry of Agriculture and Rural Affairs, Yangzhou University, Yangzhou 225127, China | htzhao@yzu.edu.cn |
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| Abstract: |
| The aim of this study is to explore the absorption pathway of Cr（Ⅲ）in maize seedlings. The effects of different Cr（Ⅲ）treatment concentrations（0–20 mg·L-1）on the Cr（Ⅲ）absorption kinetics of maize seedlings and the effects of an ATPase inhibitor, an ion channel inhibitor, and Fe（Ⅲ）on the absorption of Cr（Ⅲ）in maize seedling roots were determined using hydroponics culture. The results indicated that the maximum absorption rate（Vmax）of Cr（Ⅲ）by maize seedling roots was 121.4 mg·kg-1·d-1, which was significantly higher than the Vmax of the aboveground parts of the seedlings（16.3 mg·kg-1·d-1, P<0.05）. The affinity between the ion and ionic carrier（Km）of Cr（Ⅲ）absorbed by the roots was 12.2 mg · L-1, which was significantly lower than the Km of the shoots（180.8 mg · L-1, P<0.05）. The ATPase inhibitor, Na3VO4, significantly inhibited the uptake of Cr（Ⅲ）by maize seedling roots（P<0.05）. Neither the Ca2+ channel inhibitor, LaCl3, nor the K+ channel inhibitor, C8H20CIN, inhibited the uptake of Cr（Ⅲ）by maize seedling roots（P>0.05）. Compared with the uptake of a normal nutrient solution, the Vmax of Cr（Ⅲ）uptake by maize seedling roots with Fe（Ⅲ）deficiency increased by 20.0%, but the Km only decreased by 5.0%. However, under Fe（Ⅲ）treatment, the Vmax of Cr（Ⅲ）uptake decreased by 46.0% and the Km decreased by 56.0%. These results indicate that Cr（Ⅲ）mainly accumulated in maize seedling roots, and the transfer ability to the aboveground parts of the seedlings is relatively poor. The absorption of Cr（Ⅲ）by roots occurres via an active absorption process and is inhabited by Fe（Ⅲ）. Cr（Ⅲ）uptake is not related to Ca2+ or K+ channels. |
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