In the past few decades, cadmium (Cd) as soil contaminant is a major problem for the mankind. Cd contamination of soil and food crops is a critical environmental concern as it deteriorates the soil quality and creates threat to the food safety and human health. High Cd concentration in soils pose negative effects on the plants at physiological, structural and molecular levels. Secretion of certain secondary metabolites in the rhizosphere is a survival mechanism adopted by plants to tolerate and encounter Cd toxicity. Under metal-stressed conditions, secretion of root exudates in soil increases the external detoxification strategies of the plants. The secreted phytochemicals are gaseous compounds, inorganic and especially organic in composition. In plants, the role of these metabolites to confront Cd toxicity and induce tolerance under Cd distress is underrated. The review paper focuses on Cd sources, factors that affect its bioavailability, uptake and toxicity in the plants. Furthermore, it also highlights the contemporary progression in our understanding on the mechanisms of root exudation in plants and the effect of Cd toxicity on the root exudation. Finally, the review provides important information on the role of different root exudates to subsist Cd stress in plants naturally, particularly by reducing the dependence on synthetic amendments to enhance Cd-tolerance and its aquisition in plants.

在过去的几十年中，镉（Cd）作为土壤污染物是人类的主要问题。土壤和粮食作物的Cd污染是一个至关重要的环境问题，因为它会恶化土壤质量并威胁到食品安全和人类健康。土壤中高浓度的镉会在生理，结构和分子水平上对植物造成负面影响。根际中某些次级代谢产物的分泌是植物耐受和遇到Cd毒性的生存机制。在金属胁迫条件下，土壤中根系分泌物的分泌增加了植物的外部排毒策略。分泌的植物化学成分是气态化合物，是无机的，尤其是有机的。在植物中 这些代谢物对镉毒性和在镉胁迫下诱导耐受的作用被低估了。这篇综述文章集中于镉的来源，即影响植物中生物利用度，吸收和毒性的因素。此外，它也突显了我们对植物根系渗出机理以及Cd毒性对根系渗出的了解的当代进展。最后，该综述提供了有关不同根系分泌物自然地维持植物中Cd胁迫的作用的重要信息，特别是通过减少对合成修饰剂的依赖性来增强植物对Cd的耐受性及其对水的吸收。它还突显了我们对植物根系渗出机理以及Cd毒性对根系渗出的影响的当代理解。最后，该综述提供了有关不同根系分泌物自然地维持植物中Cd胁迫的作用的重要信息，特别是通过减少对合成修饰剂的依赖性来增强植物对Cd的耐受性及其对水的吸收。它还突显了我们对植物根系渗出机理以及Cd毒性对根系渗出的影响的当代理解。最后，该综述提供了有关不同根系分泌物自然地维持植物中Cd胁迫的作用的重要信息，特别是通过减少对合成修饰剂的依赖性来增强植物对Cd的耐受性及其对水的吸收。