Life-History Strategy Shifts in Withania somnifera (L.) Dunal (Winter Cherry) in the Face of Combined Environmental Stresses

Abstract

Withania somnifera (L.) Dunal. is a bushy evergreen plant that naturalizes dry and arid soils of subtropical regions across the world. It is widely recognized for therapeutic benefits and cultivated in rainfed areas for its drought tolerance. However, the purpose of the study is to investigate how W. somnifera adapts to different ecological conditions and the effects of these adaptations on the physio-biochemical properties of the plant. In this context, twelve populations of W. somnifera were collected from four diverse ecological ranges such as Cholistan desert (dryness ratio = 43.00–29.23, P = 101.4–149.2 mm), Thal desert (dryness ratio = 23.46–20.37, P = 185.9–213.1 mm), Rajanpur desert (Dryness ratio = 31.64–20.61, P = 137.8–211.6 mm) and Potohar Plateau (dryness ratio = 7.13–5.11, P = 611.5–850.4 mm) to explore the key anatomical and physiological modifications involved in ecological success of this species across heterogenic environmental conditions. Results showed that ionic contents, organic osmolytes, root and stem cellular area and trichome area substantially increased in Cholistan desert populations. We observed specific variations in Thal desert populations, including a higher shoot biomass and increased photosynthetic pigments, enlarged vascular bundles in stems and enlarged metaxylem and phloem areas in roots and leaves. Rajanpur desert populations were highly xeromorphic, with increased root biomass production, more leaves, thicker midribs and laminae, thicker epidermis and cortical region, sparse hairiness on leaf surfaces and deeply crypted stomata. Populations inhabiting the Potohar Plateau exhibited maximum plant height and shoot growth, large cortical cells in roots and leaves and numerous trichomes. Overall, these adaptive traits display W. somnifera resilience against environmental challenges, promising innovative applications in medicine and agriculture.