TITLE:
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
AUTHORS:
Aster Gebrekirstos, Demel Teketay, R. Mitlöhner
KEYWORDS:
Drought Tolerance, Reforestation, Domestication, Plant Water Relation, Adaptation, Acacia Woodlands, Ethiopia, Agroforestry
JOURNAL NAME:
Open Journal of Forestry,
Vol.4 No.4,
July
11,
2014
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. The recent expansion of A. oerfota and A. mellifera in the study area could be related to their tolerance of osmotic stress, which
may imply a trend of soil salinization. The division of plant responses into
categories or strategies can be valuable aid to understanding long-term plant
survival and distribution, monitor site condition and predict the direction of
future changes.