Carvalho Marcia Eugenia Amaral, Piotto Fernando Angelo, Franco Mônica Regina, Borges Karina Lima Reis, Gaziola Salete Aparecida, Castro Paulo Roberto Camargo, Azevedo Ricardo Antunes
Departamento de Genética, Escola Superior de Agricultura "Luiz de Queiroz", Universidade de São Paulo (Esalq/USP), Piracicaba, SP, 13418-900, Brazil.
Departamento de Produção Vegetal, Escola Superior de Agricultura "Luiz de Queiroz", Universidade de São Paulo (Esalq/ USP), Piracicaba, SP, 13418-900, Brazil.
Ecotoxicology. 2018 Dec;27(10):1293-1302. doi: 10.1007/s10646-018-1983-8. Epub 2018 Sep 26.
Cadmium (Cd) toxicity is frequently coupled to its accumulation in plants, but not always the highest Cd concentration triggers the worst damages, indicating that additional events influence the magnitude of Cd side-effects. We investigated the early mechanisms behind the differential Cd-induced impacts on plant development of four tomato accessions with contrasting tolerance to Cd toxicity. At organ level, the highest Cd concentration was not associated with the largest biomass losses. In leaves, changes in superoxide dismutase and catalase activities were not related to differences in Cd concentration, which was unable to provoke HO overproduction on the sixth day of plant exposure to this metal. Further investigation in the mineral profile revealed that magnitude of Cd toxicity depends probably on synergic effects from increased B status, in addition to the own Cd accumulation. Furthermore, disbalances in Mn status (i.e., excess in leaves and deficiency in roots) may enhance Cd toxicity degree. According to data, however, the low magnesium (Mg) status can be linked to tomato tolerance against Cd toxicity. In conclusion, the tomato tolerance degree under short-Cd exposure depends on actively, finely regulation of mineral homeostasis that results in different development of plant organs. The better understanding on the mode of action of Cd toxicity in plants can help in the establishment of strategies to mitigate its impacts on crop yield.
镉（Cd）毒性常与其在植物中的积累相关联，但并非总是最高的镉浓度引发最严重的损害，这表明还有其他因素影响镉副作用的程度。我们研究了四种对镉毒性耐受性不同的番茄种质在镉诱导下对植物发育产生不同影响背后的早期机制。在器官水平上，最高的镉浓度与最大的生物量损失并无关联。在叶片中，超氧化物歧化酶和过氧化氢酶活性的变化与镉浓度的差异无关，在植物接触这种金属的第六天，镉浓度并未引发过氧化氢的过量产生。对矿物质分布的进一步研究表明，镉毒性的程度可能除了自身的镉积累外，还取决于硼含量增加产生的协同效应。此外，锰状态的失衡（即叶片中过量而根部缺乏）可能会增强镉的毒性程度。然而，根据数据，低镁状态可能与番茄对镉毒性的耐受性有关。总之，短时间镉暴露下番茄的耐受程度取决于对矿物质稳态的积极、精细调节，这导致植物器官的不同发育。更好地理解镉在植物中的毒性作用方式有助于制定减轻其对作物产量影响的策略。
