Changes in fatty acids composition, hydrogen peroxide generation and lipid peroxidation of salt-stressed corn (Zea mays L.) roots

Abstract

Comparative study about the salt-induced oxidative stress and lipid composition has been realised in primary root tissues for two varieties of maize (Zea mays L.) in order to evaluate their responses to salt stress. The root growth, root water content (WC), hydrogen peroxide (H 2 O 2 ) generation, lipid peroxidation, membrane stability index and the changes in the profile of fatty acids composition were investigated. Salinity impacts in term of root growth, water content, H 2 O 2 generation, lipid peroxidation and membrane destabilisation were more pronounced in primary roots of Aristo than in those of Arper indicating more sensitivity of the first variety. It was confirmed by gas chromatography that the composition of fatty acids in roots of both varieties was constituted mainly by 16:0 and 18:0 as major saturated fatty acids and 18:1x9, 18:2x6 and 18:3x3 as major unsaturated fatty acids. Total lipid extracts from the roots of both varieties showed that the lipid saturation level increased under salt stress, notwithstanding the increased proportion of polyunsaturated fatty acids. The changes in lipid saturation being predominantly due to decreases in oleic acid (18:1x9) and increases in palmitic acid (16:0). However, Arper root extracts contained a lower proportion of saturated lipids than Aristo. The enhanced proportion of highly polyunsaturated fatty acids especially linolenic and eicosapentaenoic acids was considered to be the characteristic of the relatively salt tolerance in Arper roots.

5-Aminolevulinic acid ameliorates salinity-induced metabolic, water-related and biochemical changes in Brassica napus L.

“…Salinity stimulates hydrogen peroxide (H 2 O 2 ) production (Hernandez et al 1995;Hajlaoui et al 2009), which plays a crucial role in the mechanism of salt injury (Singha and Choudhuri 1990). Salinity enhanced the level of H 2 O 2 and superoxide anion (O 2-) generation whereas ALA application helped the salinity-treated plants to detoxify both ROS by manipulating the antioxidant enzyme activities as reported by Nishihara et al (2003) in spinach leaves.…”

Role of the Plasma Membrane in Saline Conditions: Lipids and Proteins

“…A decrease in the ratio of 18:2/18:3 reduced salt tolerance of different halophyte plants (Ivanova et al, 2006), which was related to lowered membrane fluidity. In addition, increased level of 18:3/18:2 and 20:5/20:0 ratios in roots of salt tolerant corn cultivar contributes to the tolerance of this cultivar to salt stress (Hajlaoui et al, 2009). The previous authors report that a decrease in membrane stability was greater in sensitive cultivar than tolerant one.…”

“…In agreement with that, Møller et al (2007) illustrate that salt tolerant plants may protect against the oxidative effects of salts through restructuring their membranes with less polyunsaturated fatty acids. Further support is the fact that lipid peroxidation greatly increases in salt sensitive plants under salinity (Hajlaoui et al, 2009;Jaffel-Hamza et al, 2013). Accumulation of 18:2 rather than 18:3 in the sensitive cultivar was related to more lipid peroxidation and an alteration in fatty acid desaturase activity in saline environment.…”

“…Maintaining a high degree of fatty acid unsaturation in the broccoli root PM was suggested to control membrane physicchemical properties to cope with salt stress (Table 1, Lopez-Perez et al, 2009). Other studies report that salt sensitive plants subjected to salt stress commonly show decreased levels of C18:3 in their membranes and experienced a reduction in membrane fluidity (Upchurch, 2008;Hajlaoui et al, 2009). An increase in membrane unsaturated fatty acids of Suaeda salsa also enhance salt tolerance through protection of photosystem II under salt stress (Sui et al, 2010).…”

Amelioration of salt-induced oxidative stress in eggplant by application of 24-epibrassinolide

“…Salt stress can increase ROS production, and in consequence plasma membrane leakage and the accumulation of MDA, an indicator of oxidative damage to the membranes (Athar et al 2008, Hajlaoui et al 2009). Treatment of leaves with 90 mM NaCl resulted in a marked increase in leakage of electrolytes, MDA content, superoxide production and H 2 O 2 content (Table 1).…”