Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, PR China.
Department of Horticulture, College of Agriculture, University of Sargodha, Sargodha, 40100, Pakistan.
Chemosphere. 2022 Sep;303(Pt 3):135196. doi: 10.1016/j.chemosphere.2022.135196. Epub 2022 Jun 1.
Heavy metal/metalloids (HMs) are among the primary soil pollutants that limit crop production worldwide. Plants grown in HM contaminated soils exhibit reduced growth and development, resulting in a decrease in crop production. The exposure to HMs induces plant oxidative stress due to the formation of free radicals, which alter plant morphophysiological and biochemical mechanisms at cellular and tissue levels. When exposed to HM toxicity, plants evolve sophisticated physiological and cellular defense strategies, such as sequestration and transportation of metals, to ensure their survival. Plants also have developed efficient strategies by activating signaling pathways, which induce the expression of HM transporters. Plants either avoid the uptake of HMs from the soil or activate the detoxifying mechanism to tolerate HM stress, which involves the production of antioxidants (enzymatic and non-enzymatic) for the scavenging of reactive oxygen species. The metal-binding proteins including phytochelatins and metallothioneins also participate in metal detoxification. Furthermore, phytohormones and their signaling pathways also help to regulate cellular activities to counteract HM stress. The excessive levels of HMs in the soil can contribute to plant morpho-physiological, biochemical, and molecular alterations, which have a detrimental effect on the quality and productivity of crops. To maintain the commercial value of fruits and vegetables, various measures should be considered to remove HMs from the metal-polluted soils. Bioremediation is a promising approach that involves the use of tolerant microorganisms and plants to manage HMs pollution. The understanding of HM toxicity, signaling pathways, and tolerance mechanisms will facilitate the development of new crop varieties that help in improving phytoremediation.
重金属/类金属（HMs）是全球范围内限制作物生产的主要土壤污染物之一。在 HM 污染土壤中生长的植物表现出生长和发育受限，导致作物产量下降。由于自由基的形成，HM 会诱导植物产生氧化应激，从而改变植物的形态、生理和生化机制，在细胞和组织水平上。当植物暴露于 HM 毒性时，它们会进化出复杂的生理和细胞防御策略，例如将金属螯合和运输，以确保自身的生存。植物还通过激活信号通路来诱导 HM 转运蛋白的表达，从而发展出有效的策略。植物要么避免从土壤中吸收 HM，要么激活解毒机制来耐受 HM 胁迫，这涉及到产生抗氧化剂（酶和非酶）来清除活性氧。金属结合蛋白，如植物螯合肽和金属硫蛋白，也参与金属解毒。此外，植物激素及其信号通路也有助于调节细胞活动，以对抗 HM 胁迫。土壤中过多的 HM 会导致植物形态、生理、生化和分子的改变，从而对作物的质量和产量产生不利影响。为了保持水果和蔬菜的商业价值，应该考虑采取各种措施来去除受金属污染的土壤中的 HM。生物修复是一种很有前途的方法，它涉及利用耐受微生物和植物来管理 HM 污染。对 HM 毒性、信号通路和耐受机制的理解将有助于开发新的作物品种，从而有助于提高植物修复的效果。
