Water conservation strategies through anatomical traits in the endangered arid zone species Salvadora oleoides Decne.

Abstract

Salvadora oleoides Decne. (Salvadoraceae) is a facultative and mesomorphic xerophyte, well adapted to arid and semi-aridregions. Twelve populations were selected from different ecological regions of Punjab to investigate structural modifications thatare essential for water conservation, by either improving water-storing capacity or preventing water loss from the plant body, hence,enabling this species to cope with environmental extremities. We observed significant plasticity in structural features, which ensuresecological success in a variety of environmental conditions. Huge variation was seen in various tissue systems, i.e., epidermis andepidermal appendages, collenchyma, size of internal oil glands, storage parenchyma, shape, size and arrangement of vascular tissue,intensity of sclerification, and stomatal size, shape and orientation. The desert populations showed additional parenchymatous layerunder multilayered epidermis, xylem completely surrounded by phloem, broad metaxylem vessels, intensive sclerification in and outsidevascular tissue, and numerous and small sized stomata on abaxial leaf surface. Population from salt-affected areas showed greater stemcross-sectional area, enlarge palisade parenchymatous cells, multilayered epidermis, large storage parenchyma, and sclerified vascularbundles. Roadside populations possessed sclerified vascular bundles and dense hairiness on leaf surface.