State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China; Department of Chemistry, University of Buea, Buea, PO Box 63, Buea, Cameroon.
Ecotoxicol Environ Saf. 2020 Jun 15;196:110545. doi: 10.1016/j.ecoenv.2020.110545. Epub 2020 Apr 8.
The relationship between the chemical forms of Cu and Cd adsorbed on the roots of different wheat cultivars and their phytotoxic effects on the plants were investigated. The wheat varieties Dunmaiwang (DMW), Tekang 6 (TK6), Zhongmai895 (ZM895), and Chaojixiaomai (AK68) were used. The zeta potentials of wheat roots, measured by the streaming potential method, were used to characterize root charge properties. Results indicated that the changes in zeta potential at pH 4.01-6.61 were 14.7, 15.53, 13.01, and 12.06 mV for ZM895, AK68, DMW, and TK6, respectively. The negative charge and functional groups on ZM895 and AK68 roots were greater than on DMW and TK6 roots, which led to more exchangeable and complexed Cu and Cd on ZM895 and AK68 roots and increased Cu and Cd toxicity compared to DMW and TK6. Coexisting cations, such as Ca, Mg, K, and NH, alleviated Cu and Cd toxicity to wheat roots through competition for adsorption sites on the roots, which decreased exchangeable and complexed Cu and Cd on wheat roots. The Ca and Mg were most effective in alleviating heavy metal toxicity and they decreased exchangeable Cu on AK68 roots by 39.14% and 47.82%, and exchangeable Cd by 8.51% and 28.23%, respectively.
研究了不同小麦品种根系吸附的 Cu 和 Cd 的化学形态及其对植物的植物毒性之间的关系。所用小麦品种为 Dunmaiwang（DMW）、Tekang 6（TK6）、Zhongmai895（ZM895）和 Chaojixiaomai（AK68）。采用流动电位法测定小麦根系的动电电位，用以表征根电荷特性。结果表明，在 pH 4.01-6.61 时，ZM895、AK68、DMW 和 TK6 的动电电位变化分别为 14.7、15.53、13.01 和 12.06 mV。ZM895 和 AK68 根上的负电荷和官能团多于 DMW 和 TK6 根，导致 ZM895 和 AK68 根上可交换和络合的 Cu 和 Cd 增加，与 DMW 和 TK6 相比，Cu 和 Cd 的毒性增加。共存的阳离子，如 Ca、Mg、K 和 NH，通过与根上的吸附位点竞争，减轻了 Cu 和 Cd 对小麦根的毒性，从而降低了小麦根上的可交换和络合的 Cu 和 Cd。Ca 和 Mg 对缓解重金属毒性最有效，它们分别使 AK68 根上的可交换 Cu 减少了 39.14%和 47.82%，可交换 Cd 减少了 8.51%和 28.23%。
