The short-term “memory” of a dioneia mousetrap, a carnivorous plant also known as a flycatcher, can last for about 30 seconds. What would explain this movement? The calcium concentrations in the leaf cells signal when the dioneia plant should close. That is, if an insect touches the sensitive hair of the plant only once, the trap remains immobile. But if the insect strikes again in about half a minute, the leaves of the carnivorous plant will close and trap its prey.
Mystery of dioneia, carnivorous plant
How dioneias remember this initial touch has been a mystery. But a new study reveals that plants use calcium, researchers at Nature Plants report.
Scientists already knew that some plants have long-term memory, says study co-author Mitsuyasu Hasebe, a biologist at the National Institute of Basic Biology in Okasaki, Japan. For example, vernalization is how plants remember cold periods winter as a sign to bloom in spring.
But short-term memory is a mystery and that is the first direct evidence of calcium, says Hasebe.
Dioneia is a carnivorous plant famous for its jaw-like leaves. Even if it has no brain or nervous system, it can apparently count to five and distinguish between live prey and rain, which could inadvertently cause its leaves to close, wasting energy.
The performance of calcium in the dioneia plant
Previous research has suggested that calcium plays a role in the studied process. With the help of genetic engineering, Hasebe and his colleagues were able to actually see calcium in action.
Then, the researchers added genes to the dioneias that produce a protein. It glows green when exposed to calcium.
When the team touched one of the trap’s sensory hairs, the base shone, spread across the leaf and disappeared. But when the researchers touched the hair again or a different thread on the leaf in about 30 seconds, the leaves of the trap shone even more than before and the plant closed quickly.
The results show that dioneia’s short-term memory is an increase and decrease in calcium within the leaf cells, the researchers say. Each time a sensory hair is triggered, it signals the release of calcium.
From then on, as the calcium concentration increases until it reaches a certain level reached by that second, the plant closes.
Even so, for the plant to feel the prey, the trap operates a rapid electrical network that can convert the movement of a fly or other insect into small voltage changes that propagate through the plant’s cells, says co-author Rainer Hedrich.
Therefore, scientists are still not sure how the calcium memory system works in conjunction with the electrical network to activate this poppy plant crackle.
Study published in Nature Plants.