The water parameters( Ψ° π 、 Ψ 100 π 、 RWC °、 ROWC °、 ε max etc.) in the hybrid clone seedlings of Populus tomentosa were studied under the conditions of soil water strees using Pressure Volume technique. The abilities to maintain turgor and adjust osmosis in the clones were comprehensively evaluated. The results showed that all clones examed had the abilities to increase turgor maintaining and osmotic adjustment during the water stress,but the distinction among the clones ...