Responses of plants against heavy metal-induced ROS: A Review

Abstract

Plants are vulnerable to many injurious, environmental situations like biotic and abiotic stress, ultimately affecting their growth and development. Biotic stress is caused by living organisms such as insects, nematodes, bacteria, fungi etc. On the other hand abiotic stress arise from high or low temperature, light, drought, salinity and heavy metals. Some heavy metals are important for the plant, i.e. Cu, Zn, Fe but these metals are present in the soil in very less quantity, so these are called an essential micronutrient. Toxicity of heavy metals cause a reduction in plant growth and ultimately leads to the death of the plant. Metal concentration increase in soil due to human activity or geological origin. All heavy metals are toxic, and they cause mutagenesis in the plant, animal and aquatic ecosystem also. In recent years, in agricultural practices, use of wastewater from cities has made the significant accumulation of heavy metal in soil and agricultural product. Metals are transported from water to soil that cause contamination in soil and inhibit plant growth. Heavy metal contaminations in soil and agriculture have raised potential risks to plant, human and animals. In Response to metal stress plant possesses various protective mechanisms like chelation, detoxification and so on. Plant posses many defensive strategies like antioxidative defence system, antioxidant and osmolytes that protect the plant from stress condition. This defensive system activates during stress condition. This review focus on the heavy metal effect on plant and its defensive system on the plant.