Isabgol used for antitussive and anti-inflammatory drugs, due to the existence of mucilage in the seeds. seeds of isabgol are used commercially for the production of mucilage. In order to study the effect of salinity stress on morphological and physiological traits of isabgol (plantago psyllium L.), an experiment was conducted in greenhouse as a randomized complete block design with four replications. Salinity levels applied were 0, 50, 100, 150, 200, 250, and 300 mmol/L using mixture of NaCl, MgSo4, MgCl2, and CaCl2 with the ratio of 6:2:1:1. Irrigation with water salinity started after plant establishement in pots and continued to before plant harvest. Plant fresh and dry weight, plant height, leaf area, chlorophyll fluorescence, chlorophyll content, relative water content (RWC), and electrolyte leakage (EL) was measured. Analysis of variation and duncan test (p < 0.05) were done by SAS sofrware to demonstrate the salinity effect on these traits. Results showed that the effect of salinity levels on the all of mentioned traits was significant, except minimum fluorescence (Fo) and quantum efficiency of photosystem II (

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