Lu Hai-Long, Nkoh Jackson Nkoh, Xu Ren-Kou, Dong Ge, Li Jiu-Yu
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China.
Institute of Botany, Jiangsu Province and Chinese Academy of Sciences (Nanjing Botanical Mem. Sun Yat-sen), Nanjing, China.
J Sci Food Agric. 2023 May;103(7):3531-3539. doi: 10.1002/jsfa.12505. Epub 2023 Mar 1.
Manganese (Mn) is an essential micronutrient for plants, whereas excess Mn(II) in soils leads to its toxicity to crops. Mn(II) is adsorbed onto plant roots from soil solution and then absorbed by plants. Root charge characteristics should affect Mn(II) toxicity to crops and Mn(II) uptake by the roots of the crops. However, the differences in the effects of root surface charge on the uptake of Mn(II) among various crop species are not well understood.
The roots of nine legumes and six non-legume poaceae were obtained by hydroponics and the streaming potential method and spectroscopic analysis were used to measure the zeta potentials and functional groups on the roots, respectively. The results indicate that the exchangeable Mn(II) adsorbed by plant roots was significantly positively correlated with the Mn(II) accumulated in plant shoots. Legume roots carried more negative charges and functional groups than non-legume poaceae roots, which was responsible for the larger amounts of exchangeable Mn(II) on legume roots in 2 h and the Mn(II) accumulated in their shoots in 48 h. Coexisting cations, such as Ca and Mg , were most effective in decreasing Mn(II) taken up by roots and accumulated in shoots than K and Na . This was because Ca and Mg could compete with Mn(II) for active sites on plant roots more strongly compared to K and Na .
The root surface charge and functional groups are two important factors influencing Mn(II) uptake by roots and accumulation in plant shoots. © 2023 Society of Chemical Industry.
锰（Mn）是植物必需的微量营养素，而土壤中过量的二价锰（Mn(II)）会对作物产生毒性。Mn(II)从土壤溶液吸附到植物根系上，然后被植物吸收。根系电荷特性应会影响Mn(II)对作物的毒性以及作物根系对Mn(II)的吸收。然而，不同作物物种根系表面电荷对Mn(II)吸收影响的差异尚不清楚。
通过水培法获得了9种豆科植物和6种非豆科禾本科植物的根系，分别采用流动电位法和光谱分析法测量根系的ζ电位和官能团。结果表明，植物根系吸附的可交换Mn(II)与植物地上部积累的Mn(II)显著正相关。豆科植物根系比非豆科禾本科植物根系带有更多的负电荷和官能团，这导致豆科植物根系在2小时内吸附更多的可交换Mn(II)，并在48小时内地上部积累更多的Mn(II)。共存阳离子，如Ca和Mg，在减少根系吸收并积累在地上部的Mn(II)方面比K和Na更有效。这是因为与K和Na相比，Ca和Mg能更强烈地与Mn(II)竞争植物根系上的活性位点。
根系表面电荷和官能团是影响根系对Mn(II)吸收以及在植物地上部积累的两个重要因素。© 2023化学工业协会。
