Responses of Dobera glabra and Eight Co-Occurring Species to Drought and Salinity Stress at a Savanna-Scrub Ecotone: Implications in the Face of Climate Change

Abstract

To quantify the resistance of different co-occurring species to drought and osmotic stress (salinity stress), plant water (Ψ) and osmotic (Ψp) potentials were measured during the dry season. We applied a pressure chamber and cryoscopy to measure Ψ and Ψp, respectively. The species revealed a wide range of responses to water stress (−0.83 to −5.8 MPa) and osmotic stress (−1.3 to −3.2 MPa) and not all plants fit closely into one or the other category. Evergreen species tended to have lower Ψ than deciduous species. Notably, Dobera glabra, well known as drought indicator tree in the region, showed the lowest Ψ (up to −5.8 MPa) and Ψp (−3.2 MPa). This indicates its outstanding drought and osmotic stress tolerance and explains its ability to thrive in drought prone areas and years.