Ecological resilience of Gallon's curse (Cenchrus biflorus Roxb.) in hyperarid and hypersaline environments

Cenchrus biflorus Roxb., a resilient C₄ grass species, thrives across hyperarid and hypersaline environments due to its remarkable structural and functional plasticity. This study investigated ecotypic variations in morpho-anatomical and physiological traits among populations collected from ecologically distinct sites in Pakistan, including saline deserts, arid plains, and semi-arid regions. Morphological adaptations such as reduced leaf area, enhanced root biomass, and increased leaf number were evident under arid stress. Anatomical modifications—including thickened epidermis and endodermis, enlarged cortical and parenchymatous regions, narrow metaxylem vessels, and high trichome and bulliform cell densities—contributed to water conservation and ion regulation. Physiological resilience was linked to elevated levels of osmoprotectants (proline, glycine betaine, soluble sugars), stress enzymes (catalase, peroxidase, superoxide dismutase), antioxidants, and photosynthetic pigments. Ion homeostasis was maintained through restricted Na⁺ uptake and compartmentalization. Multivariate analyses revealed strong associations between environmental variables (temperature, salinity, soil nutrients) and trait expression. The findings highlight the critical role of phenotypic plasticity in the ecological success of C. biflorus, underscoring its potential utility in arid land restoration and climate-resilient forage development.