Investigating physiological and biochemical

3.3.2.14 Lipid peroxidation (MDA) 
The level of lipid peroxidation in plant tissues, expressed as malondialdehyde 
(MDA), was determined according to Hodges et al. (1999). Fresh samples (0.5 g) 
were homogenized in 4.0 ml of 1% trichloro acetic acid (TCA) solution and 
centrifuged at 10,000×g for 10 min. The supernatant was added to 1 ml 0.5% (w/v) 
TBA made in 20% TCA. The mixture was heated in boiling water for 30 min and the 

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reaction was stopped by placing the tubes in an ice bath. The samples were 
centrifuged at 10,000×g for 10 min, and the absorbance of the supernatant was 
recorded at 532 nm. Correction of non-specific turbidity was made by subtracting the 
absorbance value read at 600 nm. The level of lipid peroxidation was expressed as 
nmol g
-1
fresh weight by using its molar extinction coefficient of 0.155 mM cm
-1
.
3.3.2.15 Statistical analysis 
All the data presented in this study are mean of three replications and standard 
errors (SE). Analysis of variance (ANOVA) was performed by using a statistical 
package, Statistix 8.1. Significant differences among treatments were considered at 
the P ≤ 0.05 level.
3.3.3. Results 
Physiological parameters 
3.3.3.1 Relative water contents (RWC) and electrolyte leakage (EL) 
 
To assess the plant water status, relative water content (RWC) is easy to measure 
and widely used method for assessing plant water status while electrolyte leakage (EL) 
shows degree of membrane damage under stress conditions. Addition of NaCl in the 
growth medium caused significant reduction in relative water contents (RWC) of all 
four linseed genotypes (Table 3.3.1). On the other hand, salt application significantly 
increased the EL of all the genotypes under stress. There was no significant variation 
among linseed genotypes for their RWC and EL, however, salt tolerant genotypes 
maintained relatively higher RWC than salt sensitive genotypes. Contrary to that, 
these genotypes showed less EL as compared to salt sensitive genotypes at all the 
treatment levels. The maximum RWC was noted in salt tolerant genotype 637-72 
(21.50%, 15.77%) followed by NO-303 (21.47%, 15.73%) at 100 mM and 200 mM 
NaCl while at 100 mM NaCl, the minimum RWC was noted in salt sensitive S-907 
(21.10%) genotype while at 200 mM the minimum RWC 15.57%. Unlike RWC, EL 
was the maximum in salt sensitive genotypes and the minimum in salt tolerant 
genotypes. The increase in EL of all the genotypes was much pronounced at higher 
salinity of 200 mM NaCl and it was 26.27% and 26.10% in 637-72 and NO-303 

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