Investigating physiological and biochemical

 
3.3.2. Materials and methods 
3.3.2.1 Seedling growth and treatments 
The experiments were conducted in rain protected wire house of Zhejiang 
University, Hangzhou, China and plant analyses were completed in College of 
Agriculture and Biotechnology, Zhejiang University. Seeds of two salt tolerant 
genotypes 637-72 and NO-303 and two salt sensitive genotypes S-907 and C-99-3-115 
(based on previous screening experiments, conducted in wire house of Saline 
Agriculture Research Centre, Institute of Soil and Environmental Sciences, University 
of Agriculture, Faisalabad, Pakistan) were germinated in moist quartz sand in green 
house. Fifteen days old seedlings with uniform growth were selected and transplanted 
into 20 L containers covered with a foamed plastic plate containing evenly spaced holes. 
The containers contained half strength Hoagland’s nutrient solution (Hoagland and 
Arnon, 1950). The design of the experiment was CRD with factorial arrangement 
using three replicates. After one week of transplanting, salinity levels (control, 100 
and 200 mM) were developed with NaCl salt in three increments, whereas in control 
no salt was added. The solution pH was adjusted to 6.5±0.5 throughout the 
experiment with 1 M NaOH or HCl, as required. The nutrient media in the pots was 
continuously aerated using aquatic pumps and media was changed after every five 
days. Measurements were made after 30 days of salt stress.

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Physiological parameters
 
3.3.2.2 Photosynthetic rate (P
n
) and Stomatal conductance (g
s
) 
 
P
n
and g
s
were measured in cloudless clear days at light-saturating intensity 
between 11.00 and 12.00 hours on the uppermost, fully expanded leaves, using Infrared 
Gas Analyser (IRGA), LICOR-6200 portable photosynthesis system (LI-COR Lincoln, 
NE, USA).