COMPARISON OF HYDRAULIC PRESS AND PRESSURE CHAMBER ESTIMATES OF POTATO LEAF WATER POTENTIAL

The leaf water potential of field-grown Russet Burbank potato plants (Solarium tuberosum L.) was estimated with a pressure chamber and a leaf press to assess the usefulness of the leaf press for evaluation of potato leaf water status. Paired leaflets were used for leaf water potential estimation with both instruments. Leaflets were taken from potato plants exposed to excessive soil moisture and high relative humidity, from plants with adequate soil moisture, and from plants under severe water stress. Over the range from -0.28 to -1.61 MPa, for 124 leaflet pairs, the leaf press estimates of leaf water potential were exponentially related (r2 = 0.85) to pressure chamber estimates. The leaf press compared well with the pressure chamber in the range from -0.6 to -1.2 MPa. © 1990 Springer.