Contrasting adaptations to drought stress in field-grown Ziziphus mauritiana and Prunus persica trees: Water relations, osmotic adjustment and carbon isotope composition

Abstract

Drought resistance strategies of Ziziphus mauritiana Lamk. and peach (Prunuspersica L.) were studied, focusing on changes in leaf water potential, carbon isotope composition, and solute and stress metabolite contents during an annual cycle under natural rainfed conditions at a field site in Zimbabwe. After a 100-d drought period, leaf water potential (Ψ(leaf)) of peach trees decreased to -2.0 MPa, whereas Ψ(leaf) of Z. mauritiana remained constant at -0.7 MPa. Values for the natural abundance of 13C (δ13C) of bulk peach leaves as well as of total water-soluble compounds and soluble sugars of leaves increased gradually, resulting in significantly higher values as drought stress developed, ind..