Copper in plants

Abstract

Copper is an essential metal for normal plant growth and development, although it is also potentially toxic. Copper participates in numerous physiological processes and is an essential cofactor for many metalloproteins, however, problems arise when excess copper is present in cells. Excess copper inhibits plant growth and impairs important cellular processes (i.e., photosynthetic electron transport). Since copper is both an essential cofactor and a toxic element, involving a complex network of metal trafficking pathways, different strategies have evolved in plants to appropriately regulate its homeostasis as a function of the environmental copper level. Such strategies must prevent accumulation of the metal in the freely reactive form (metal detoxification pathways) and ensure proper delivery of this element to target metalloproteins. The mechanisms involved in the acquisition of this essential micronutrient have not been clearly defined although a number of genes have recently been identified which encode potential copper transporters. This review gives a briefly overview of the current understanding of the more important features concerning copper toxicity and tolerance in plants, and brings information of recent findings on copper trafficking including copper detoxification factors, copper transporters and copper chaperones.

Effect of excess iron and copper on physiology of aquatic plant Spirodela polyrrhiza (L.) Schleid

“…In our experiment, significant correlation was obtained between Fv/Fm and excess iron and copper (r 5 20.9742, r 5 20.9790, P \ 0.05), suggesting ROS caused by excess metal concentration damaged photosynthetic apparatuses severely. Previous studies indicated that heavy metals primarily disturbed the integrity of thylakoid membranes and changed their fatty acid composition (De Vos et al, 1991), interfered with the biosynthesis of photosynthetic machinery and decreased net photosynthetic rate (Cook et al, 1997;Yruela, 2005).…”

Copper-stress induced alterations in protein profile and antioxidant enzymes activities in the in vitro grown Withania somnifera L.

“…Though Cu is an essential micronutrient for normal plant growth and metabolism, but it can be toxic to the plants at higher concentration (Yruela 2005). It has been reported that, excess of Cu can inhibit the growth of plant height, root elongation and causes damage to root epidermal cells (Tanyolac et al 2007;De Vos et al 1989).…”

“…As a result, the formation of the hydroxyl radical is prevented since it is produced by the interaction of superoxide and H 2 O 2 being catalyzed by transition metal ions (Halliwell and Gutteridge 1999;Weckx and Clijsters 1996). Opposite results are reported where the activities of these enzymes decreased with the increase in heavy metal concentration; this can be caused by either the direct action of ROS on the proteins or on the inhibition of protein synthesis (Yruela 2005). Our results show both the effects for CAT activity.…”

“…It acts as the cofactor in many enzymes such as Cu/ Zn SOD, cytochrome c oxidase, amino oxidase, laccase, plastocyanin and polyphenol oxidase (Halliwell and Gutteridge 1984). However, Cu induces toxicity at tissue concentrations slightly above its optimal levels (Yruela 2005;Halliwell and Gutteridge 1999). Studies from some plant species demonstrate that excess Cu in the plant growth medium induced alterations in the photosynthetic and respiratory processes, enzyme activity, DNA and membrane integrity, all of which could lead to growth inhibition (Salt et al 1998).…”

“…• ─ ), hydrogen peroxide (H 2 O 2 ), singlet oxygen ( 1 O 2 ) and hydroxyl radicals (OH • ) (Sharma et al 2012;Yruela 2005;Ercal et al 2001). The ROS has a role in lipid peroxidation, membrane damage and consequently in plant senescence (Halliwell and Gutteridge 1999;Fridovich 1986).…”