Chapter4 - Crucial plant processes under excess of metals/metalloids and tolerance through omics approaches

Abstract

In earth heavy metals are an integral part, they can be both essential and nonessential. Soils polluted with heavy metals (HMs) have become common due to increase in geologic and anthropogenic activities. Significant environmental pollutants such as lead, nickel, cadmium, cobalt, and mercury cause plant toxic impact; reducing productivity and posing hazardous threats to agri-ecosystems are thus significant environmental pollutants. It affects the growth of plant due to phyto-toxicity. HMs interfere with the seed germination, growth of the plant and production mainly related to plant system physiology, biochemistry and genetic elements. HMs have a significant impact on seeds, cause defects and decrease germination by affecting the digestion and mobilization of food reserves in germinating seeds leads to seed toxicity and productivity loss. Accumulation of HMs is greatly influences the morphology of plants by cell degeneration and thickening of cell walls. It increases in the amount of treacherous elements in vascular cylinder and even ruptures the parenchyma tissue. HMs impede the action of important enzymes and obstruct the plant biochemical aspect like photosynthesis, pigment synthesis and most commonly the inhibit electron transport chain which contribute to the generation of radicals cause oxidative damage. It also decreases the vegetative growth of plants and increases the sign of senescence. In soil HMs levels cause osmotic disturbances in plants, they are known for effects on root growth, transport of water and transpiration. It alters the profile of genomic DNA and increase the rate of DNA methylation. To consider above facts, this chapter discussed the effects of HMs on important plant processes and tolerance through omics approaches.