The Venus flytrap employs quick electrical impulses to ensnare its prey, triggered by touch or stress. However, the specific molecular mechanism responsible for this touch sensation has remained a subject of investigation. Recent research conducted by Japanese scientists has shed light on this intriguing process, with their findings published in the journal Nature Communications.
The Venus flytrap draws in unsuspecting insects with a sweet, fruity aroma. Upon landing on the leaf, an insect activates highly sensitive trigger hairs, which, if pressured enough, bend sufficiently to initiate the trap’s rapid closure. As the leaves snap shut, long cilia within the trap secure the insect, analogous to grasping fingers, while the plant begins secreting digestive enzymes. The insect is then slowly digested over a period of five to twelve days, after which the trap reopens, allowing the desiccated remains to be released into the environment.
In 2016, Rainer Hedrich, a biophysicist at Julius-Maximilians-Universität Würzburg in Germany, led research that demonstrated the Venus flytrap’s ability to “count” the number of touches on its leaves. This capability allows the plant to differentiate between potential prey and non-edible items such as small stones or deceased insects. The flytrap first detects a single action potential but refrains from snapping shut immediately, awaiting a second stimulus to confirm the presence of prey. The trap only fully closes and initiates digestion after the hairs are triggered a total of five times.
In 2023, scientists created a bioelectronic device designed to further investigate the intricate signaling mechanism of the Venus flytrap. Their research confirmed that the initial electrical signal originates in the plant’s sensory hairs and spreads outwards in a radial pattern without a specific directional preference. Notably, some signals appeared spontaneously, arising from sensory hairs that had not yet been activated.
Glowing green
This recent study builds on a 2020 investigation by the same Japanese team, which genetically modified a Venus flytrap to gather insights into its short-term “memory.” They introduced a gene for a calcium sensor protein known as GCaMP6, which emits a green fluorescence when it binds to calcium. This unique glow facilitated the researchers’ ability to visualize fluctuations in calcium levels in response to stimulation of the plant’s sensitive hairs with a needle. They concluded that the variations in calcium concentrations within the leaf cells appear to function as a form of short-term memory for the Venus flytrap, although the precise interactions between calcium levels and the plant’s electrical signaling remain to be fully understood.
