Plants have evolved to become extremely sophisticated organisms. Animals rely on their ability to move to look for food, run away from danger, and find new resources. Plants, instead, are stationary and have had to adapt in order to produce their own nutrients, efficiently taking advantage of the resources at their disposal, and interacting with their environment.
Proof that plants have excelled at adapting to their surroundings is that of all the lifeforms on earth, they are the most numerous and the longest-living. They boast an infinite number of records, and they are remarkably sensitive: plants react and record fifteen different chemical and physical parameters (our meager five senses pale in comparison), most of which are perceived through their roots. Plants are extraordinarily adaptable: they are able to survive in extreme environments by economising energy and resources. To survive, they even signal dangers to one another. They also establish synergetic and cooperative relationships not only amongst themselves but to other living beings as well. One example of this is how they reproduce: some plants produce sophisticatedly-shaped seeds to facilitate their distribution, others have evolved to depend on insects or small animals who are attracted to sugars and other volatile substances contained in flowers, so that they, subsequently, spread the flowers’ pollen.
If we consider intelligence as the ‘capacity to solve problems’, it is evident that plants are extremely creative problem solvers.
1. Plants camouflage themselves remarkably well.
Take the example of the Boquilla Trifoliata.
Photo credit: Scott Zona
The Boquilla Trifolata is a plant found in Chilean and Argentinian forests. It is a climbing plant, a liana, which grows by rooting itself to the trunks of the plants whereon it climbs. It is able to imitate its hosts, sometimes adopting more than one shape at a time. If necessary, a single Boquilla plant can vary the appearance of its leaves multiple times, its goal is to mimic its host species as closely as possible. The Boquilla leaf may be tapered, pointed, or rounded, sometimes even spiked or ridged. It can vary in shape, size, proportion, color, orientation, and texture.
The ability to camouflage its leaves is an extraordinary defense strategy. By modifying its leaves, the Boquilla can disguise itself, becoming unrecognisable to its predators.
So what’s its secret?
The answer is as simple as it is surprising: plants are able to perceive images, thanks to their plant-specific ocelli. The ocelli are a sort of ‘lens’ located in the leaves’ epidermis. They are able to communicate images relating to shape and colour, and they convey these images together with nutrients from the sun’s rays.
2. Plants elaborate sophisticated strategies to reproduce.
Let’s take a look at the Erodium Cicutarium
How plants spread their seeds is a delicate subject: for example, it is important that the seeds be distributed over as vast an area as possible, and the external conditions must be ideal for germination. Plants have developed hundreds of strategies to efficiently disseminate their seeds. In the case of the Erodium cicutarium, a natural plant in the same family as the geranium (Geraniaceae), this strategy is literally explosive.
The fruit of the Erodium, through its structure, makes a great deal of mechanical energy available to its seeds, with a sort of spring mechanism. When the flowers are mature, or when external factors (animals, insects, or a gust of wind) intervene, the seeds are freed in a mini-explosion that can carry them meters away. But wait, there’s more! Once the seeds have landed on the ground and have adjusted to their new environments according to the air’s humidity, they begin a brilliant process of auto-planting, taking advantage of their pointed shape, brushes, and a long, curled appendix — a kind of tail that is able to curl itself into a spiral. First, the seed uses its brushes to position itself vertically, with its head down. When it is stable, the curly tail begins modifying its shape according to the change in humidity. This generates a spiral movement which pushes the seed downward into the earth. In just a few days, the seed has reached its ideal position underground, a few centimeters below the surface, and it is ready to germinate.
3. Plants have memory: the Mimosa Pudica
Plants are able to recognise and remember dangerous stimuli. They record information and behave accordingly.
The Mimosa Pudica is a fascinating little plant which closes its leaves when it feels threatened: just a slight touch is enough to provoke this protective reaction. If, however, it is subjected to the same stimulus more than once, without being damaged or hurt, the Mimosa Pudica will stop reacting defensively. It recognises that the contact poses no threat, and thus has no need to activate its defensive mechanisms. This is fascinating in and of itself, but that’s not all. If the mimosa pudica is exposed to the very same stimulus a month later, the repetition of the stimulus continues to be perceived as non-threatening and the leaves remain open! This is an astounding result which shows that the Mimosa Pudica not only registers information, it is able to remember it as well.
4. Plants know how to count: the talent of the Dionaea Muscipula
Commonly known as the ‘Venus flytrap’, the Dionaea Muscipula is the epitome of a carnivorous plant and its image has taken hold in our collective imagination.
We can easily visualise its fleshy, threatening leaves, which resemble jaws with a set of sharp teeth capable of imprisoning its unfortunate prey with extremely quick movements. What most of us are not aware of, however, is that before the Dionaea Muscipula decides to act, it makes a few calculations. The movement used to capture prey requires a great deal of precious energy which must not be wasted. The digestion of prey is equally if not more laborious: it produces enzymes and is a very demanding process for the carnivorous plant.
Its leaves are sensitive to contact, but they must not allow themselves to be tricked into reacting by false alarms. So how does this plant distinguish the sensation of a delicious insect walking over it from the feel of raindrops falling on its surface? By counting. The leaves of the Dionaea Muscipula are covered in tiny hairs which receive contact stimuli. The hairs must be touched twice to activate the trap. At this point, they must be touched three more times for the plant to decide that it has captured live prey, and begin the digestive process. This somewhat macabre discovery is shocking: the plants not only recognise and distinguish between different stimuli, they also know how to count them. An incredible cost-benefit evaluation.
Finally, we must regard plants with new and deeper understanding. And let us keep in mind that plants are extraordinary. If it weren’t for plants, we wouldn’t eat and we wouldn’t have any oxygen to breathe.
PNAT is an academic spin-off from the University of Florence which combines sustainable design with the latest experimental research into plant life.
PNAT is a think-tank that was co-founded by the biologists Stefano Mancuso (Director LINV – International Laboratory of Plant Neurobiology), Elisa Azzarello, Camilla Pandolfi and Elisa Masi, and the designers Antonio Girardi and Cristiana Favretto.
Under the guidance of plant neurobiologist Stefano Mancuso, PNAT installed the first prototype of the Fabbrica dell’Aria (Air Factory) in B9, a device that purifies the air inside buildings by using plants’ natural ability to absorb and break down atmospheric pollutants