Quantifying Root Turgor Using Dew Point Hygrometry

Water potential is the driving force behind the movement of water within the soil-plant-atmosphere continuum. Measuring water potential and its components provides valuable information about plant- and root water relations, including osmoregulation. Here, we describe a straightforward method for determining water and osmotic potential, as well as cell turgor in roots, using dew point hygrometry. The chapter begins with a brief overview of issues related to plant and root water potential, and then proceeds to describe the principles and measurement procedures of dew point hygrometry in more detail, including calibration, equilibration, and sample preparation. Practical recommendations are provided to minimize common error sources. This methodology may be useful for researchers studying plant-water balance, root water uptake, plant stress physiology, and osmoregulation.