Variation in Growth and Water Uptake of Atriplex halimus and Atriplex nummularia Plants in Relation to Water Deficit

The variation in water deficit stress tolerance in terms of biomass production and water uptake of Mediterranean saltbush (A. halimus) and Australian saltbush (A. nummularia) was investigated in this study. One-year-old seedlings of the two species were grown in containers in the field at the University of Jordan, Jubeiha station. Plants were subjected to four water levels (100%, 75%, 50% and 25% ETo). Plants were sampled at three dates; June, September and December, for leaves, stems and roots dry weight and for leaves area and root length measurement and for water uptake and use efficiency (WUE) estimation. Reducing water level below 75% ETo reduced biomass production, leaves area (LA), and root length density (RLD). On the other hand, reducing water level increased WUE and root-to-shoot ratio. Biomass production was reduced mostly by 69% in response to stress (25% ETo). Root growth was also affected by water stress; where root dry weight (RDW), and RLD were reduced by values ranging 25%-72% compared to the 100% ETo. Atriplex nummularia had higher biomass, RL, RLD, RDW, and LA, than A. halimus. Water use efficiency was increased with increasing water deficit. This increase was higher at June (92%) as compared to September and December samplings. Atriplex halimus had a higher WUE than A. nummularia especially at high stress (25% ET).

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