The influence of water stress and air velocity on growth of Impatiens walleriana and Petunia × hybrid

Impatiens walleriana ‘DeZire’ and Petunia × hybrid ‘Tidal Wave’ were subjected to a combination of water stress and exposure to wind to evaluate the potential application of these treatments as an alternative to chemical growth retardation. Air velocities evaluated were 0.1, 0.2, 0.4, 0.8, 1.5, and 4.5 m s−1 and irrigation treatments were either control or 45% water stress based on irrigation occurring when the weight of the plant (plant, pot and peat) was reduced by 25% (control) or 45% (water stress) of the initial weight. The experiment was repeated twice; once in spring and once in summer.Water stress did not significantly influence growth of Impatiens while increasing air velocity resulted in decreasing plant height, but the only significant effect was obtained at air velocity of 4.5 m s−1. Air velocities at or over 0.8 m s−1 resulted in significantly lower fresh weight of the plants, while dry weight was significantly lower at air velocities higher than 0.1 m s−1.The plant height of Petunia was different in the two replicates and an interaction between water stress and air velocity was determined in the first replicate, in which air velocity did not influence plant height of water stressed plants. Water stressed plants of Petunia had significantly lower fresh weight of the plants and increased air velocity reduced the number of flower buds and fresh and dry weight of the plants.

Research highlights▶ The combination of water stress and increased air velocity is a potential tool for control of plant height. ▶ The combination of water stress and increased air velocity is an environmental friendly method. ▶ The method might in future substitute chemical growth retardation.