When we think about movement, we picture animals, people, or vehicles. But… what about plants?
Although they have no muscles, skeleton, or locomotor system, plants also move. They do so in a subtle way, often imperceptible to the naked eye, yet highly efficient.
These movements respond to environmental stimuli and are key to their survival. They can occur due to changes in cell turgor pressure (the entry or exit of water into cells) or through uneven growth that causes the plant to bend, coil, or even burst.
1. Tropisms
Slow and permanent movements involving growth in a specific direction, usually in response to an environmental stimulus.
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Phototropism: growth towards light, very visible in young stems or leaves.
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Geotropism: response to gravity, with roots growing downward and stems growing upward.
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Thigmotropism: response to touch, typical of climbing plants such as beans or vines.
2. Nastic movements
Unlike tropisms, nastic movements do not involve growth. They are reversible and often rapid, always in response to an external stimulus.
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Nyctinasty: leaves or flowers close at night and open during the day, in movements reminiscent of “sleep”.
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Thigmonasty: rapid movement upon touch, as in Mimosa pudica when touched.
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Thermonasty: response to temperature changes, as in plants that open or close flowers depending on heat or cold.
3. Opening and closing movements
A clear example is stomata: small pores mostly located on leaves that close or open depending on light, humidity, and the amount of carbon dioxide accumulated inside the leaves. This allows the plant to transpire and exchange gases with the environment as needed.
4. Seed, fruit, and spore dispersal
Some plants have developed spectacular mechanisms to disperse their seeds, fruits, or spores to ensure the colonisation of new spaces. Examples include pods that suddenly burst with a slight touch, launching seeds over a distance. Other species release spores using a spring-like effect, with structures that dry out or tighten and then, when released, project the spores into the air. This happens, for instance, in some ferns or mosses, which take advantage of humidity changes to open and spread them.
In short, although they do not move like animals, plants are much more dynamic than we imagine. Their movements help them grow, protect themselves, reproduce, and adapt to their environment. At the Marimurtra Botanical Garden, you will find many examples; you just need to observe carefully.
