Oxidative injury and antioxidant enzymes regulation in arsenic-exposed seedlings of four Brassica napus L. cultivars

Abstract

Environmental contamination due to arsenic (As) has become a major risk throughout the world; this affects plant growth and productivity. Its accumulation in food chain may pose a severe threat to organisms. The present study was carried out to observe the toxic effects of As (0, 50, 100, and 200 μM) on physiological and biochemical changes in four Brassica napus cultivars (ZS 758, Zheda 619, ZY 50, and Zheda 622). Results showed that As toxicity provoked a significant inhibition in growth parameters of B. napus cultivars and this reduction was more obvious in cultivar Zheda 622. The highest concentration of MDA, H2O2, and O2 (-) contents in both leaf and root tissues were observed at 200 μM As level, and a gradual decrease was observed at lower concentrations. Increasing As concentration gradually decreased chlorophyll and carotenoids contents. Activity of antioxidant enzymes such as SOD, CAT, APX, GR, and GSH was positively correlated with As treatments in all cultivars. The microscopic study of leaves and roots at 200 μM As level showed the disorganization in cell organelles. Disturbance in the morphology of chloroplast, broken cell wall, increase in size, and number of starch grains and immature nucleus were found in leaf ultrastructures under higher concentration of As. Moreover, damaged nucleus, diffused cell wall, enlarged vacuoles, and a number of mitochondria were observed in root tip cells at 200 μM As level. These results suggest that B. napus cultivars have efficient mechanism to tolerate As toxicity, as evidenced by an increased level of antioxidant enzymes.

Assessing the Correlations between Different Traits in Copper-Sensitive and Copper-Resistant Varieties of Jute (Corchorus capsularis L.)

“…Furthermore, phytotoxicity of Cu causes injury at the cellular level to many cellular organelles, which causes the generation of reactive oxygen species (ROS) [4,6]. Moreover, high concentrations of Cu in the soil enhance the production of ROS by producing superoxide radicals (O −1 ) and singlet oxygen ( 1 O 2 ) in the Mehler reaction [5,8], which leads to lipid peroxidation and the production of high contents of malondialdehyde (MDA) in plant tissues/cells, which induces oxidative damage in plants due to the phytotoxicity of Cu [7,13,17,18]. ROS production in plants is removed by a variety of antioxidant enzymes such as SOD, POD, CAT, and APX.…”

Physiological and iTRAQ‐Based Quantitative Proteomics Analysis of Methyl Jasmonate–Induced Tolerance in Brassica napus Under Arsenic Stress

“…Among the metal pollution, arsenic (As) is considered as most hazardous element in the environment because of its toxic effect on plants and have possible carcinogenic effects in humans . The toxic effects of As have been extensively reported in plants, either in an artificial condition or in soils resulting in the disruption of several morpho‐physiological, and biochemical mechanisms and As‐induced oxidative damage due to lipid peroxidation in plants . Plants have developed different processes for tolerating the heavy metal stress, including As‐stress, such as compartmentalization, complexation with small molecules PCs (phytochelatins), exclusion, and the synthesis of stress‐response proteins .…”

Modulation of arsenic-induced oxidative stress and protein metabolism by diphenyleneiodonium, 24-epibrassinolide and proline in Glycine max L.

“…Hence, reduced germination and growth responses are possibly due to the detrimental effects of As on the cellular functioning of the plants, where most of the available energy is consumed in the formation of stresslinked essentials like phytochelatins, anti-oxides, etc. (Farooq et al 2015). Similarly, reduced DM is possibly an outcome of As-promoted increase in membrane permeability and thereby loss of electrolytes and other important constituents of the cell, essentially required for growth and development processes.…”

“…As revealed lesser accumulation of As, possibly by preventing entry of it via the maintenance of the structures of the plasma membranes and cell walls and the modification of As-transporters. Inside the cell, As readily binds with sulfhydryl groups of both proteins and enzymes, consequently inhibiting cellular metabolism, which finally results in cell death (Farooq et al 2015). Results of TTC test revealed a notable fall in the vitality of As-stressed Glycine max L. tissue, which was in agreement with the report of Kaur et al (2012) in Phaseolus aureus L. On the other hand, in protective treatments, exogenous DPI, EBL or Pro, more precisely Pro, maintained the vitality of Glycine max L. radicles, up to a large extent, even under As-stress.…”

“…A plant's root serves as the foremost and most susceptible site for the perception of abiotic stress responses including Astoxicity. After entering into the plant's body, As readily binds with sulfhydryl groups of both proteins and enzymes, thereby perturbing the cellular metabolism and inhibiting enzy-matic activities (Farooq et al 2015). A well-known consequence of As-toxicity is over-production of reactive oxygen species (ROS) such as superoxide (O 2˙ˉ) , hydroxyl radical (˙OH) and hydrogen peroxide (H 2 O 2 ), affecting the oxidative condition inside the plants (Siddiqui et al 2015, Chandrakar et al 2016b.…”