Microstructural adaptations of snow bush (Aerva javanica (Burm.f.) Juss. Ex Schult.) in desert ecosystems

Aerva javanica (Snowbush) is a perennial xerophytic shrub native to South Asian deserts, recognized for its pivotal role in soil stabilization, desert rehabilitation, and ecosystem resilience. However, the structural basis of its survival across contrasting edaphic and climatic regimes remains poorly understood. This study aimed to elucidate the adaptive modulation of growth and anatomical traits of A. javanica across three ecologically distinct regions: (i) the Saline Cholistan Desert, (ii) the Cholistan Desert Margins, and (iii) the Thal Desert Margins, representing a gradient of salinity and aridity stress. Morphological assessments demonstrated that plant vigor decreased with increasing salinity-shoot and root lengths, biomass, and leaf area were highest at Thal (MGR) and lowest at saline core sites (CHM, RYK). Conversely, high-salinity populations developed denser root systems and greater leaf succulence, reflecting adaptive strategies for osmotic regulation and water-use efficiency. Anatomical investigations using fluorescent stereo microscopy revealed profound structural differentiation across habitats. Populations from the Saline Cholistan Desert exhibited thickened epidermis, enlarged cortical parenchyma, and expanded vascular bundles with additional xylem formation-traits enhancing hydraulic conductivity and salt exclusion. The Cholistan Desert Margins displayed intermediate anatomy with balanced vascular and storage tissues, indicating transitional adaptation to fluctuating moisture and ion availability. In contrast, Thal Desert Margin plants showed thinner dermal tissues, reduced sclerenchyma, and well-developed chlorenchyma, emphasizing photosynthetic optimization and rapid biomass accumulation. Moreover, the species exhibited novel xylem vessel development within cortical and endodermal root regions and specialized glandular and non-glandular foliar trichomes. These coordinated structural adaptations enhanced hydraulic efficiency and water conservation, reinforcing its dominance and persistence in hyper-arid desert ecosystems. Collectively, these results demonstrate a hierarchical adaptive framework from hydraulic safety to growth efficiency, underscoring A. javanica exceptional structural plasticity. Future integrative studies employing transcriptomic and metabolomic approaches are recommended to elucidate the genetic and biochemical mechanisms governing this adaptive continuum and to inform climate-resilient restoration strategies for arid landscapes.