Abstract:

The results and characteristics of water potential measurements with four different methods, namely the Chardakov method, Pressure chamber, in situ hygrometry and leaf disc hygrometry were compared on several plants species. Experimental results showed that the former 3 methods produced similar results, but the leaf disc hygrometry yielded significant different results from the other 3 methods. Further investigation showed that the results with the leaf disc hygrometry varied considerably with the equilibrium time and was not able to show the actual water potentials of the plants. The Chardakov method was time-consuming, and its efficiency was very low. Pressure chamber was able to provide accurate and reliable measurements of plant water potentials if the sample water loss could be avoided and the repetitious samples were available. While the in situ hygrometry showed the merits such as more reliable results, non-destructive to plants, no harsh prerequisites for plants and could measure the same spot of a plant continuously.

Key words: water potential, pressure chamber (Scholander bomb), in situ hygrometry, leaf disc hygrometry, chardakov method