Oxidative stress indicators as selection tools for salt tolerance

Abstract

Oxidative stress indicators, malondialdehyde (MDA) accumulation and chlorophyll retention, were tested as tools for salt‐tolerance screening in Chloris gayana (Kunth), a forage grass exhibiting inter‐ and intra‐cultivar variability in the response to salt stress. Three types of experimental system were compared, salt shock, gradual salt treatment and leaf segments floated on control and saline solutions. Results followed the same trend in the three systems, but leaf segments or gradually salinized plants are the most convenient. Lower mean MDA and higher mean chlorophyll content were found under salinity in cv. ‘Katambora’, which is considered, from previous field trials, to be more salt tolerant than cv. ‘Boma’. Nevertheless, chlorophyll content did not give consistent results in other tests and it is not recommended for selection purposes. Within cv. ‘Boma’, clones rating higher in a salt tolerance evaluation under greenhouse conditions had lower MDA content under salinity and lower mean MDA ratios between salt‐treated and control samples. The survival of 80‘Boma’ plants under increasing NaCl concentration was assessed and MDA was measured in the leaves of very plant before the final NaCl level was reached, to assess whether it was predictive of survival capability. MDA values were significantly lower in the group surviving longer, thus, a selection based on low MDA values would have enriched the original population with more tolerant individuals.

Oxidative damage and antioxidant defenses as potential indicators of salt-tolerant Cenchrus ciliaris L. genotypes

“…3 and 4). Foliar MDA content was consistent with salt tolerance in Oryza sativa, Setaria viridis and tomato cultivars (Juan et al, 2005;Kim et al, 2004;Vaidyanathan et al, 2003) and with findings from our previous work on salt tolerance in Chloris gayana diploids (Luna et al, 2000(Luna et al, , 2002 and in Chloris gayana tetraploids (unpublished data). It should be noted that in the latter, foliar MDA showed that it can be a heritable character.…”

“…It should be noted that in the latter, foliar MDA showed that it can be a heritable character. All these evidences suggest that foliar MDA content level might be considered a suitable salinity tolerance indicator in Cenchrus ciliaris L. genotypes, as Luna et al (2000) proposed for Chloris gayana. The other possible indicator of salt tolerance could be • O 2 − content in roots.…”

“…At early time points, their response to oxidative damage was measured as total SOD and CAT activities, two key antioxidant enzymes involved in salinity stress (Ashraf, 2009). Malondialdehyde (MDA), a product of membrane lipids peroxidation, was also selected on the basis of previous works (Luna et al, 2000(Luna et al, , 2002 suggesting that foliar MDA content would be a good salinity tolerance marker in Chloris gayana. Nitrobluetetrazolium (NBT) reduction was used to evaluate • O 2 − content in roots under salinity stress because it has been documented as a tool to identify individuals tolerant of aluminum stress (Maltais and Houde, 2002).…”

Salt resistance of tomato species grown in sand culture

“…Chlorophyll extraction was carried out on fresh fully expanded leaf material; 1 g leaf sample was ground in 90% acetone using a pestle and mortar. The absorbance was measured with a UV/Visible spectrophotometer (Pye Unicam SP6-550, UK) and chlorophyll concentrations were calculated using the equation proposed by (Luna et al 2000).…”

Physiological Responses of Three Contrasting Plant Species to Groundwater Level Changes in an Arid Environment

“…When under water stress, plant cells actively accumulate certain types of solutes such as free proline (Pro) and soluble sugar to improve their drought-resistance by lowering water potential and maintaining turgor pressure Maggio et al 2004;Sofo et al 2001). Accumulation of the end product of membrane lipid peroxidation, malondialdehyde (MDA), is also a result of the oxygenation of plant membrane lipids under stress conditions (Ye and Zhao 2002;Luna et al 2004;Yamamoto et al 2001). Superoxide dismutase (SOD) and peroxidase (POD) are the main anti-oxidizing agent of plants for cleaning out excessive active oxygen to protect membrane structure, and thus strengthen their resistance to adverse circumstances (Ren et al 2001;Cavalcanti et al 2001;Babitha et al 2002;Zoller et al 2003;Jin et al 2004;Ederli et al 2004).…”