By Mili Jayadeep | Science Editor
The Venus flytrap is a carnivorous plant that has fascinated scientists for centuries. It has flat, wide and open leaves and sensitive ‘hairs’ that are involved in the entrapment of its prey; for example if an insect touches the hairs on the plant just once, the leaves stay still. However, on second touch, the plant tightly shuts. This phenomenon is associated with some form of memory within the plant. Until recently, how the plant has the ability to have a short-term memory has been a puzzle.
A new study has published its findings showing how memory is associated with calcium signalling in an online report in Nature Plants. Mitsuyasu Hasebe, co-author and biologist at the National Institute for Basic Biology in Okazaki, Japan says, “Scientists know that some plants have a type of long-term memory… this is the first direct evidence of the involvement of calcium.”
Despite the absence of a nervous system or brain unlike in carnivorous animals for instance, the Venus Flytrap can tell the difference between actual prey and environmental stimuli such as rain. This is a brilliant adaptation to conserve energy for use when real prey falls trap on the leaves.
Earlier research shows that calcium does contribute to this action. Hasebe and fellow researchers were able to unveil the action of calcium on the plant using genetic engineering methodology. This enabled the team to visualise calcium signalling as it would appear as a green glow due to the addition of a fluorescent protein.
Activating the sensory hairs the first time showed a fainter glow compared to when activated the second time within 30 seconds by tapping the sensory hairs. When the hairs were touched again, the glow was stronger showing evidence of memory, which is when the plant consequently snapped to close the leaves in response. Their work shows that this is owing to calcium signalling where when threshold calcium levels are reached, as indicated by the green fluorescence. The activation of the hairs subsequently causes the plant to shut in attempt to trap its prey.
The plant is still of great interest due its unique carnivorous adaptations. Rainer Hedrich, another co-author and biophysicist at the university of Würzburg, Germany also describes how it senses prey: “the flytrap operates a fast electrical network”,which translates the movement of its prey into electricity that can be sensed by the plant’s cells. The mystery still remains in how the electrical network and the memory capabilities work in conjunction with each other to cause the shutting of the leaves.
Andrej Pavlovič, a plant physiologist at Palacký University in Olomouc, Czech Republic although not associated with the study is as excited as other scientists to uncover such findings: “But the most interesting part of the research was getting the trap to glow”
Uncovering more secrets of carnivorous plants is research to be celebrated, which is why scientists like Pavlovič are optimistic about being able to manipulate the plant’s genes to observe this phenomenon. Pavlovič agrees that it, “is a great leap forward in studies on carnivorous plants.” With further study, scientists are hopeful to discover more secrets of the enticing carnivorous plants of the natural world.