Whole-Plant Water Use and Hydraulics of Populus euphratica and Tamarix ramosissima Seedlings in Adaption to Groundwater Variation

Riparian phreatophytes in hyperarid areas face selection pressure from limiting groundwater availability and high transpiration demand. We examined whole-plant water use hydraulic traits Populus euphratica Tamarix ramosissima seedlings to understand how they adapt variations. These species coexist the Tarim River floodplain of western China. Measurements were performed on 3-year-old grown lysimeters simulating various depths. P. had relatively greater leaf area-specific due its comparatively higher sapwood area ratio (Hv). A Hv indicates that has a limited capacity support area. also showed significantly leaf-specific conductivity (ksl) than T. but both similar sapwood-specific conductivities (kss). Therefore, it was rather kss which accounted for interspecific difference ksl. When not directly available, ksl increased. This response favors loss control, limits plant growth. In contrast, is more capable using deep groundwater. Stomatal sensitivity increasing leaf-to-area vapor deficit euphratica. Overall, less effective at compensating transpirational level. For this reason, restricted riverbanks, whereas occurs over wide range