Thigmomorphogenesis

Thigmomorphogenesis (Thigma --> to touch in Greek) is the response by plants to mechanical sensation (touch) by altering their growth patterns. In the wild, these patterns can be evinced by wind, raindrops, and rubbing by passing animals.

Botanists have long known that plants grown in a greenhouse tend to be taller and more spindly than plants grown outside. M.J. Jaffe discovered in the 1970s that regular rubbing or bending of stems inhibits their elongation and stimulates their radial expansion, resulting in shorter, stockier plants.^[1]

Growth responses are caused by changes in gene expression. This is likely related to the calcium-binding protein calmodulin, suggesting Ca²⁺ involvement in mediating growth responses.^[2]

References

1. Jaffe, MJ (1973). "Thigmomorphogenesis: The response of plant growth and development to mechanical stimulation". Planta 114 (2): 143–157. doi:10.1007/bf00387472. Retrieved March 15, 2015.
2. Braam J, Davis RW (1990). "Rain-, wind-, and touch-induced expression of calmodulin and calmodulin-related genes in Arabidopsis". Cell 60 (3): 357–364. doi:10.1016/0092-8674(90)90587-5. Retrieved March 15, 2015.

• Biro, RL; Hunt, ERJr; Erner, Y; Jaffe, MJ (1980). "Thigmomorphogenesis: Changes in cell division and elongation in the internodes of mechanically perturbed or ethrel treated bean plants". Annals of Botany 45: 655–664.
• Biro, RL; Jaffe, MJ (1984). "Thigmomorphogenesis: Ethylene evolution and its role in the changes observed in mechanically perturbed bean plants". Physiol Plant 62: 289–294. doi:10.1111/j.1399-3054.1984.tb04575.x.
• Erner, Y; Jaffe, MJ (1982). "Thigmomorphogenesis: The involvement of auxin and abscisic acid in growth retardation due to mechanical perturbation". Plant and Cell Physiol 23: 935–941.
• Erner, Y; Jaffe, MJ (1983). "Thigmomorphogenesis: Membrane lipid and protein changes in bean plants as affected by mechanical perturbation and ethrel". Physiol Plant 58: 197–203. doi:10.1111/j.1399-3054.1983.tb04169.x.