We have previously shown that the proton-ATPase activity of root plasma membrane is closely involved in low temperature resistant characteristics of plants in order to lower the osmotic potential for subsequent water uptake (Ahn et al., 1999). In the present study we tried to further verify this hypothesis, by using cucumber and figleaf gourd plants as low temperature sensitive and resistant species, respectively. We tried to localise calcium in the cells, measured kinase activities of roots and leaves, and recorded patterns of water transport with heat-balance sap- flow gauge.