Influence of an Antitranspirant and a Hydrogel on Net Photosynthesis and Water Loss of Cineraria during Water Stress

Cineraria plants ( Senecio cruentus DC) were transplanted into medium either with or without a hydrogel (polyethylene oxide). Half the plants in each medium were treated with a film-forming antitranspirant while half were not. Plants then were placed either in a clear glasshouse or a shaded glasshouse (40% shade), and no additional water was applied. Water loss was lowest for plants where both the foliage and medium were treated, whereas control plants (no treatment) lost water most rapidly regardless of light intensity. Plants which received only the hydrogel were similar in water loss to control plants at both light intensities. As water stress developed, net photosynthesis (Pn) decreased, reaching a zero rate at wilting; however, Pn measurements of treated leaves showed few significant differences due to treatment during the water stress period.