3.2.3 Effects Of Heavy Metals On Plants
2.3.3 Effects of heavy metals on plants
Plants are sensitive for both, deficient and excess availability of some of the heavy metal ions. In which some of them at low concentration are compulsory micronutrients, while the same at higher concentrations such as Cd, Hg, As are intensely toxic to the metabolic activities of the plants (Reeves and Baker, 2000; Fernandes and Henriques, 1991). Agricultural soil is contaminated by heavy metals, has become a critical environmental concern due to their potential adverse ecological effects. Hence, toxic elements are considered as soil pollutants due to their widespread occurrence and their acute and chronic toxic consequences on plants grown of such soils.
2.3.3.1 Effect of Zinc on plants
Zinc has a …show more content…
Plants grown in soil containing high levels of Cd show visible signs and symptoms of damage reflected in terms of chlorosis, growth inhibition, root tips browning and lastly death of plants (Sanita di Toppi and Gabbrielli, 1999; Wojcik and Tukiendorf 2004; Mohanpuriaet al. 2007; Guo et al. …show more content…
Iron is a most significant constituent of the cell redox schemes such as hemeproteins including cytochromes, catalase, peroxidase and leghemoglobin and iron sulfur proteins like acontiase, ferredoxin, and superoxide disumutase (SOD) (Marschner, 1986). The appearance of iron toxicity symptoms in leaf tissues arises only under flooded state, which involves the microbial reduction of insoluble Fe3+ insoluble Fe2+ (Beckerand and Asch, 2005). The toxicity in plants due to iron is linked to high Fe2+ uptake by roots and its transportation or movement to leaves and via transpiration stream. The Fe2+ surplus causes free radical production that spoils cellular structure irreversibly and damages membranes, DNA and proteins, reduction of plant photosynthesis and yield (Sinha et al. 1997; Arora et al. 2002; Dorlodot et al. 2005; Nagajyotiet al.
Plants are sensitive for both, deficient and excess availability of some of the heavy metal ions. In which some of them at low concentration are compulsory micronutrients, while the same at higher concentrations such as Cd, Hg, As are intensely toxic to the metabolic activities of the plants (Reeves and Baker, 2000; Fernandes and Henriques, 1991). Agricultural soil is contaminated by heavy metals, has become a critical environmental concern due to their potential adverse ecological effects. Hence, toxic elements are considered as soil pollutants due to their widespread occurrence and their acute and chronic toxic consequences on plants grown of such soils.
2.3.3.1 Effect of Zinc on plants
Zinc has a …show more content…
Plants grown in soil containing high levels of Cd show visible signs and symptoms of damage reflected in terms of chlorosis, growth inhibition, root tips browning and lastly death of plants (Sanita di Toppi and Gabbrielli, 1999; Wojcik and Tukiendorf 2004; Mohanpuriaet al. 2007; Guo et al. …show more content…
Iron is a most significant constituent of the cell redox schemes such as hemeproteins including cytochromes, catalase, peroxidase and leghemoglobin and iron sulfur proteins like acontiase, ferredoxin, and superoxide disumutase (SOD) (Marschner, 1986). The appearance of iron toxicity symptoms in leaf tissues arises only under flooded state, which involves the microbial reduction of insoluble Fe3+ insoluble Fe2+ (Beckerand and Asch, 2005). The toxicity in plants due to iron is linked to high Fe2+ uptake by roots and its transportation or movement to leaves and via transpiration stream. The Fe2+ surplus causes free radical production that spoils cellular structure irreversibly and damages membranes, DNA and proteins, reduction of plant photosynthesis and yield (Sinha et al. 1997; Arora et al. 2002; Dorlodot et al. 2005; Nagajyotiet al.