Bae Bumhan, Park Hyesun, Kang Sua
Department of Civil & Environmental Engineering, Gachon University, Seongnam 13120, Korea.
Toxics. 2022 Apr 16;10(4):195. doi: 10.3390/toxics10040195.
Heavy metal is one of the most frequent soil contaminants and contaminated soils generally include numerous metals. Although exposure to multiple metals may increase the toxicity to humans and ecosystems, only additive effects are considered in the risk assessment. In this study, the synergistic effect of heavy metals (Cu and Zn) on a model plant, , was quantified by the isobolographic method. The plant was cultured via the growth assay method on a plant agar containing individual heavy metals or combinations of Cu + Zn in a growth chamber. The concentration of Cu varied by eight levels from 0 to 200 μM and the concentration of Zn also varied by eight levels from 0 to 400 μM. In the combination of metals, each of the three levels of Cu (25-75 μM) and Zn (20-100 μM) were applied. After 8 days, plants were harvested for root/shoot weight and measured for leaf chlorophyll and carotenoid content. The primary and secondary root elongation of was estimated using image analysis to calculate total root length. The EC50 values of Cu and Zn on , based on the total root length, were 40.0 and 76.4 μM, respectively. When two heavy metals were administered in combination, the EC values decreased less than those of the individual metals. The average value of the combination index was 0.6, proving the synergistic toxic effect on the root growth of . As a result, the isobolograhic method is a useful tool for estimating the quantitative toxic effect of chemicals on plants.
重金属是最常见的土壤污染物之一，受污染的土壤通常含有多种金属。尽管接触多种金属可能会增加对人类和生态系统的毒性，但在风险评估中仅考虑相加效应。在本研究中，采用等效线法对重金属（铜和锌）对模式植物的协同效应进行了量化。通过生长测定法在生长室中含有单一重金属或铜 + 锌组合的植物琼脂上培养该植物。铜的浓度从0到200 μM分为八个水平，锌的浓度也从0到400 μM分为八个水平。在金属组合中，分别应用了三个水平的铜（25 - 75 μM）和锌（20 - 100 μM）。8天后，收获植物以测量根/茎重量，并测定叶片叶绿素和类胡萝卜素含量。使用图像分析估计的主根和次根伸长以计算总根长度。基于总根长度，铜和锌对的半数效应浓度（EC50）值分别为40.0和76.4 μM。当两种重金属联合施用时，EC值下降幅度小于单一金属。组合指数的平均值为0.6，证明了对根生长的协同毒性作用。因此，等效线法是评估化学物质对植物定量毒性效应的有用工具。
