Antioxidant responses to enhanced generation of superoxide anion radical and hydrogen peroxide in the copper-stressed mulberry plants

Abstract

The aim of the study was to implicate the generation of reactive oxygen species (ROS) and altered cellular redox environment with the effects of Cu-deficiency or Cu-excess in mulberry (Morus alba L.) cv. Kanva 2 plants. A study of antioxidative responses, indicators of oxidative damage and cellular redox environment in Cu-deficient or Cu-excess mulberry plants was undertaken. While the young leaves of plants supplied with nil Cu showed chlorosis and necrotic scorching of laminae, the older and middle leaves of plants supplied with nil or 0.1 microM Cu showed purplish-brown pigmented interveinal areas that later turned necrotic along the apices and margins of leaves. The Cu-excess plants showed accelerated senescence of the older leaves. The Cu-deficient plants showed accumulation of hydrogen peroxide and superoxide anion radical. The accumulation of hydrogen peroxide was strikingly intense in the middle portion of trichomes on Cu-deficient leaves. Though the concentration of total ascorbate increased with the increasing supply of Cu, the ratio of the redox couple (DHA/ascorbic acid) increased in Cu-deficient or Cu-excess plants. The activities of superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6), peroxidase (EC 1.11.1.7), ascorbate peroxidase (EC 1.11.1.11) and glutathione reductase (EC 1.6.4.2) increased in both Cu-deficient and Cu-excess plants. The results suggest that deficiency of Cu aggravates oxidative stress through enhanced generation of ROS and disturbed redox couple. Excess of Cu damaged roots, accelerated the rate of senescence in the older leaves, induced antioxidant responses and disturbed the cellular redox environment in the young leaves of mulberry plants.

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

“…However, the activity tends to decrease at longer exposure (14 days) at the highest Cu concentration. Several authors have reported an increase in SOD activity with Cu stress in Morus alba (Tewari et al 2006) and Elsholtzia splendens (Peng et al 2006). Similar results were also observed in GPX activity.…”

Copper (Cu) stress affects carbon and antioxidant metabolism in Coffea arabica seedlings

“…2A and 2B). Similar results were observed in Phaseolus vulgaris (Bouazizi et al, 2010), Morusalba (Tewari et al, 2006), Beta vulgaris (Henriques, 1989) and Nicotiana tabacum (Raeymaeker et al, 2003). H 2 O 2 acts as a signal in response to plant stress and in supra-optimal concentrations becomes toxic to membranes, affecting its permeability, which can lead to cell death (Soares et al, 2016;Capaldi et al, 2015).…”

Heavy Metals in Crop Plants: Transport and Redistribution Processes on the Whole Plant Level

“…Heavy metals present at elevated levels may cause an increased production of reactive oxygen species (ROS) in plant cells on one hand [42][43][44][45][46][47][48][49][50][51] and may be involved in the enzymatic detoxification of ROS on the other hand [2,3,42,[52][53][54]. Stresses (e.g., drought, heat and high light intensity) may also cause an accumulation of ROS and of ROS-damaged cell constituents [54,55].…”