Investigating physiological and biochemical

 
 

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List of Figures 
Figures 
Title 
Page
3.1.1 
Graph showing the relative growth parameters of linseed (genotypes from best to worst 
performing) 
35 

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3.1.2 
Graph showing the relative ion (Na+, K+) contents in linseed genotypes (genotypes from 
best to worst performing) 
35 
3.1.3 
Dendrogram showing the separation between clusters (groups) 
40 
3.2.1 
Distribution of Na+ ion in different parts of linseed genotypes at different salinity levels 
66 
3.2.2 
Distribution of K+ ion in different parts of linseed genotypes at different salinity levels 
67 
 
 
 
 
 
 
 
 
 
 
 
 
 

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ABSTRACT 
Salinity is one of the biggest problems in soils of Pakistan due to its arid to semi-arid 
climate. A rapid increase in population, industrialization of arable lands along with water 
scarcity and poor quality ground water compels us to find new ways to tackle salinity. 
Salt-affected soils can be used for growing non-conventional multipurpose crops. Linseed is 
a medicinal and oil seed crop which can be grown on salt-affected land. To explore the 
genetic variation for salt tolerance and to investigate the physiological and biochemical traits 
of linseed (Linum usitatissimum L.), sixty genotypes of linseed were grown for four weeks in 
solution culture using three salinity levels (control, 100 and 200 mM NaCl). On the basis of 
biomass and K
+
/Na
+
ratio, linseed genotypes (637-72, NO-303) and (S-907, C-99-3-115) were 
selected as salt tolerant and salt sensitive respectively. Subsequently, physiological and 
biochemical traits of salt tolerant were evaluated in solution culture and their yield and oil 
contents were determined in pot culture experiment under same set of treatments. Results 
revealed that germination and seedling growth were significantly affected due to salinity 
and linseed genotypes did not show distinct variation some in physiological traits like 
relative water contents (RWC), electrolyte leakage (EL), chlorophyll contents, stomatal 
conductance, carbonic anhydrase (CA), nitrate reductase (NR) and leaf osmotic potential but 
at the same time, photosynthetic rate, organic osmolytes especially glycine betain and 
antioxidants SOD, POD and APX were affected significantly and hence give a clue of their 
functional importance in conferring salt tolerance in linseed. Controlled entry of Na
+
ion at 
root level, active uptake of K
+
, enhanced activity of antioxidant enzymes and reduction in 
lipid peroxidation seems to be the salt tolerant traits in native linseed genotypes. 
Furthermore, it was noted that at high salinity (200 mM NaCl), crop failed to reach maturity, 
however, seeds were produced at low salinity (100 mM NaCl). The results indicated that 
linseed genotypes are sensitive to higher level of salinity (200 mM NaCl) and express 

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tolerant to salinity at vegetative stage, thus can be grown on salt-affected soils for some 
biomass production. 
Keywords: linseed, physiological, biochemical, indicators, organic osmolytes, antioxidant 
enzymes, yield, oil contents