Thigmomorphogenesis:
Thigmomorphogenesis is a phenomenon observed in plants in response to physical disturbances such as wind or touch. This adaptive response typically results in a reduction of stem elongation and an increase in stem diameter, leading to the development of shorter and sturdier plants. Such structural changes help plants withstand mechanical stress in their natural environments, making them less prone to damage compared to taller, more slender varieties. The response is particularly significant in plants grown indoors, where the absence of mechanical stimuli can lead to thinner, weaker structures that struggle when transplanted outdoors. [EBSCO]
Say that five times fast. Noted in “Why stroking seedlings can help them grow big and strong,” James Wong, NewScientist (3 January 2026, paywall):
Chemical growth regulators are one answer, helping produce sturdier, more compact plants. However, many of these substances aren’t available to home gardeners. Fortunately, research has shown that mechanical stimulation – simply rubbing, shaking or stroking seedlings – is also remarkably effective at reducing etiolation. This is all down to a phenomenon called thigmomorphogenesis, where plants alter their growth patterns in response to forces such as touch, wind, rain or vibration, by growing thicker stems, more supportive tissues and an overall shorter, stockier stature. Although scientists are still unravelling exactly how plants sense and translate these signals at the cellular level, numerous studies demonstrate that mechanically stimulated seedlings are not only structurally sturdier, but also more resilient to threats like pests and drought.
