Thigmomorphogenesis: The Interaction of Wind and Temperature in the Field on the Growth of Phaseolus vulgaris L.

Abstract

Field and laboratory experiments were performed to determine the interaction of wind and temperature on thigmomorphogenesis (defined here as decreased elongation and increased internodal radial enlargement due to mechanical perturbation). Kidney bean plants (Phaseolus vulgaris L. cv. Red Cherokee Wax) were sheltered or exposed to wind for 10 days. Wind velocity, wind gusting, temperature, light and rainfall were measured for the duration of each of ten experiments. Stem elongation and diameter were measured and it was found that thigmomorphogenesis due to wind occurs naturally. There was more internodal secondary xylem produced in the wind-exposed plants than in the sheltered plants. The experimental data were analyzed by multiple linear regression and the wind was found to be a significant factor in the prediction of bean stem elongation and thickening. Laboratory experiments show that as wind velocity increases, thigmomorphogenesis increases in an approximate linear fashion. Furthermore, it was found that low temperatures interact with mechanical perturbation to reduce the amount of thigmomorphogenesis, both in the field due to wind and in the laboratory due to rubbing. Other environmental factors do not seem to interact with the wind to modulate thigmomorphogenesis even though these factors affect plant growth.