Leaf osmotic potentials of 104 plant species in relation to habitats and plant functional types in Hunshandak Sandland,Inner Mongolia,China

Leaf osmotic potentials ( _s) of 104 plant species from different habitats, i.e., fixed sand dunes, lowland and wetlands in Hunshandak Sandland, Inner Mongolia, China, were investigated. The values of _s were strongly species-specific, and varied from –6.54 MPa ( Caragana microphylla), to –0.44 MPa ( Digitaria ischaemum); 75% of plants investigated had _s from –1.01 to –3.0 MPa. Shrubs were found to have the lowest _s, with an average value of –3.19 MPa, while grasses showed the highest _s. The order of plant _s is shrubs<trees<grasses. The result may relate to anatomical features of shrubs. C₄ photosynthetic pathway plants showed lower _s values. The _s values of 104 species were negatively correlated with their rooting depths ( r ²=0.42; P <0.001). High hydraulic pressure resulting from the deep roots may well explain this trend. The value of _s increased as the environment became wetter, ranging from –0.79 MPa in wetlands to –2.09 MPa in fixed sand dunes. Although soil salt content was higher in wetlands, we did not find any effect on _s.An erratum to this article can be found at