Investigating physiological and biochemical

3.2.3.10. Effect of salt stress on Na
+
 contents in leaves
In leaves, Na
+
build up is thought to be injurious and cause disruption of 
chlorophyll pigments as well as photosynthetic apparatus. Thus it causes adverse 
affects when accumulated in leaves in high concentration. Concentration of Na
+ 
in the 
leaves of linseed genotypes were highly affected by the application of salinity (NaCl) 

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84 
and Na
+
contents were significantly increased between control and 200 mM NaCl 
(Table 3.2.6). Significant difference was found between salt tolerant and sensitive 
genotypes and overall the maximum Na
+
contents were measured in the leaves of salt 
sensitive genotypes while the minimum Na
+
contents were recorded in the leaves of 
salt tolerant genotypes. With increased NaCl concentration, the Na
+
contents in the 
leaves of all linseed genotypes increased progressively. The maximum increase in Na
+
contents of leaves was noted at the highest NaCl concentration of 200 mM. 
Concentration of Na
+
in the leaves of S-907 and C-99-3-115 increased from 0.14% to 
3.55% and 0.18% to 3.42% respectively while in 637-72 and NO-303, Na
+
contents 
increased from 0.22% to 3.37% and from 0.14% to 3.44% respectively at 100 mM 
NaCl. At 200 mM NaCl, Na
+
concentration in the leaves of salt sensitive genotypes 
S-907 and C-99-3-115 (4.51%) were almost equal to that in the salt tolerant genotypes 
637-72 and NO-303 (3.34-4.51%) (Table 3.2.6). There was no significant difference 
between salt tolerant (NO-303 and 637-72)
genotypes and salt sensitive genotypes 
(C-99-3-115 and S-907) at control but linseed genotypes remained different in their 
leaf Na
+
concentration at increasing levels of salinity. Overall, Na
+
build up was more 
in the leaves of salt sensitive genotypes which might impose adverse effects on the 
growth of these genotypes.