Physiological and morphological effects of film-forming antitranspirants on herbaceous ornamentals
McKenney, Cynthia B.
Suppression of transpiration by film-forming antitranspirants on Petunia x hybrida and Salvia splendens was evaluated as a method of reducing water stress in retail and landscape conditions. Cloud Cover and Folicote antitranspirants were tested at three dilutions of their recommended rate under greenhouse and garden conditions. Transpiration, stomatal conductance and leaf temperature were measured using a Licor 1600 steady state porometer and were found to be not statistically altered by varying treatment concentration. Merrill leaf cutter psychrometers were used to determine the effects of the films on the water potential of both crops. Neither species was found to be affected significantly. However, high concentrations of antitranspirant did significantly improve the relative water content of Petunias in a garden environment. The effect of antitranspirant treatment on growth and development was also tested. Leaf number, leaf area, area per leaf, flower size, and number of flowers per plant were evaluated throughout the experiment. Some phytotoxicity, possibly due to the carriers in Cloud Cover and Folicote antitranspirants, were noted on both crops. A considerable gain in plant appearance or growth must result from application of these films to warrant the expense of the application.