Phragmites is a well-known genus of the family Poaceae, in Pakistan, and this genus consists of only two species, i.e., Phragmites australis and Phragmites karka. In the present work, structural and functional modifications of Phragmites were evaluated under salt stress. Different populations of Phragmites australis were collected from fifteen different habitats to appraise the morpho-anatomical and physiological modifications in terms of salinity tolerance. By using Minitab statistical software, the data were analyzed for the Analysis of variance for comparison of mean values. Between morpho-anatomical and physiological characteristics the Correlation coefficient was drained. In Phragmites australis populations from high saline habitats limited the uptake of Na⁺ supplemented by a high uptake of K⁺ and Ca²⁺ in the root and shoot while there was a maximum accumulation of total free amino acids, proline and total soluble sugars. Extensive aerenchyma formation in the cell of the leaf epidermal area, and the region of the cortex also contributed to salinity tolerance. Under salt stress, bulliform cells in leaves were highly developed, so leaves could roll to reduce water and accumulate excess amounts of toxic salts. The root and shoot dry weight, the number of stomata, stomatal size, shoot length, epidermal thickness, phloem area, and chlorophyll contents were decreased due to salt stress. However, an increasing effect of salt stress was observed on sclerenchymatous thickness, aerenchyma cells, cortical cell area, metaxylem area, bulliform cell area, trichomes length and density, stomatal density and area. These species can be effectively used to re-vegetate salt-affected areas, as well as for the phytoremediation of salt-affected lands. It was concluded that Phragmites are a widespread perennial grass and have the potential to survive in all heterogenic environments by making variations in their structural and functional features. In the future number of genetically identical markers can be isolated from this species to improve the crop productivity and tolerance level.

Keywords: Abiotic factors; C₄ grass; Distributional pattern; Structural modifications; Species composition