The effect of excess copper on growth and physiology of important food crops: a review

Abstract

In recent years, copper (Cu) pollution in agricultural soils, due to arbitrary use of pesticides, fungicides, industrial effluent and wastewater irrigation, present a major concern for sustainable agrifood production especially in developing countries. The world's major food requirement is fulfilled through agricultural food crops. The Cu-induced losses in growth and yield of food crops probably exceeds from all other causes of food safety and security threats. Here, we review the adverse effects of Cu excess on growth and yield of essential food crops. Numerous studies reported the Cu-induced growth inhibition, oxidative damage and antioxidant response in agricultural food crops such as wheat, rice, maize, sunflower and cucumber. This article also describes the toxic levels of Cu in crops that decreased plant growth and yield due to alterations in mineral nutrition, photosynthesis, enzyme activities and decrease in chlorophyll biosynthesis. The response of various crops to elevated Cu concentrations varies depending upon nature of crop and cultivars used. This review could be helpful to understand the Cu toxicity and the mechanism of its tolerance in food crops. We recommend that Cu-tolerant crops should be grown on Cu-contaminated soils in order to ameliorate the toxic effects for sustainable farming systems and to meet the food demands of the intensively increasing population.

Potential for Phytoextraction of Cu by Sesamum indicum L. and Cyamopsis tetragonoloba L.: A Green Solution to Decontaminate Soil

“…Increased level of Cu in the soil decreases root length which directly influences root growth and specific superficial area, decreasing the absorption capacity of water and nutrients. The shoot length was decreased consequently because of Cu hindrance with metabolic system of the plants which reduced mineral elements uptake and increased substantial amount of Cu inside the growing shoot that results yellowing of leaf, i.e., chlorotic symptoms due to mineral nutrients deficiency and eventually leading to stunted plant growth (Muhammad et al 2015).…”

“…Plant biomass is an excellent indicator for describing the growth and developmental changes of plants within the prospect of heavy metal toxicity. The reduction in plant biomass might be related with disturbed metabolic activities because of decreased take-up of fundamental mineral nutrients when developed under Cu toxicity (Muhammad et al 2015). Moreover, plants species which can generate high shoot (above-ground) biomass and have the capacity to accumulate heavy metals could be utilized for phytoextraction purposes including exclusion of heavy metals from contaminated soil.…”

“…Studies have demonstrated the take-up of metals; their distribution and translocation to various plant parts and also the extent of tolerance is reliant on the metal, its bioavailability, the plants species and their metabolic systems (Rohan et al 2013). The Cu accumulation capacity exceptionally differs among various plants species, based on their availabilities in the soil and also influenced by different soil conditions, as reviewed by Muhammad et al (2015). …”

“…Ag and Au) Cu has broadly utilized as a part of an extensive variety of activities, for example, fungicides and pesticides, wood additives, pigments used in glasses, paints and furthermore as a superconductor (Rebecca 2006). Cu is considered as basic essential micronutrient (trace element) in low concentration for animal (Wintz et al 2002) and plant biological functions (Mahmood and Islam 2006;Muhammad et al 2015). In an enzyme chemical reaction, Cu acts as cofactor and activator enlightening enzymes/substrate metal complex (Mildvan 1970) and in addition, serves as catalysts for homogeneous and heterogeneous chemical reactions.…”

“…Agricultural soil receives a substantial amount of Cu from environmental contamination that came about because of anthropogenic activities which frequently utilize Cu for agricultural farming, industrial and mechanical purposes (Jiang et al 2004). The inappropriate, inequitable and untreated utilization of Cu-containing pesticides to manage plant pests, diseases and infections have brought about the surplus accumulation of Cu in agricultural soil profile (Mackie et al 2012;Muhammad et al 2015). Some of the distinguished anthropogenic activities including mining and smelting operations, industrial and urban activities, inorganic-organic fertilizers, liming, sewage sludge and wastewater for irrigation are the most common sources of Cu to the agricultural soil (Herawati et al 2000).…”