From scorching sands to survival: adaptive tale of the genus Tribulus (T. longipetalus, T. terrestris and T. pentandrus) in desert ecosystem

Abstract

Desertification poses a major ecological threat, demanding insights into plant adaptive strategies for survival in arid landscapes. Tribulus species, i.e., T. longipetalus, T. terrestris, and T. pentandrus, are drought-tolerant herbs commonly distributed across arid and semi-arid regions. Samples from natural populations were collected from diverse ecological zones of the Cholistan Desert exhibiting varying levels of drought intensity and resource availability. In the present study, structural and functional modifications in three Tribulus species under desert stress conditions were evaluated. It was hypothesized that each species would exhibit species-specific morphological, physiological, and anatomical adjustments to optimize survival under desert stress. All three species responded distinctly under different environmental conditions. The most notable feature in T. longipetalus under drier habitats was enhanced accumulation of total soluble proteins, sugars, amino acids, and thicker dermal and vascular tissues supporting stress endurance. T. terrestris exhibited better performance in highly stressful zones, showing increased shoot biomass, soluble osmolytes, and maximum chlorophyll content. T. pentandrus showed vigorous growth in less stressful habitats with highest pigment content and shoot biomass, whereas populations from dry sites displayed increased metaxylem and vascular bundle size. Structural and functional traits such as well-developed vascular bundles, Kranz-type leaf anatomy with thickened mesophyll and bundle sheath cells, and increased epidermal and sclerenchymatous tissues contributed to water retention, transport efficiency, and mechanical support. Significant variability in stomatal traits among species reflected adaptive strategies for gas exchange and water conservation. It was concluded that Tribulus species developed specific anatomical and physiological strategies crucial for ecological fitness, resource use efficiency, and survival under desert stress conditions. These adaptive features enhance their potential for desert reclamation and ecological restoration.

Graphical Abstract