The plant memory mechanism is still being studied and attracting attention. Plants respond to memory by remembering specific experiences through various factors. This ability improves the survival ability of plants. There are many procedures for this.

Signal Recognition

Several factors are used in plants to recognize signals. Phytochrome, a pigment protein in plants that absorbs light and changes the shape of the absorption spectrum, is present in all plants and detects the wavelength of light. Furthermore, it regulates the growth of the plants and activates signal transduction pathways that induce physiological responses according to the stimulation. Abscisic acid is one of the plant hormones that is involved in regulating physiological responses in plants. For example, it sends a signal to close the stomata to prevent water loss. Plants are sensitive to temperature and respond differently depending on the temperature. However, plants themselves do not have temperature receptors. Therefore, plants use various proteins to detect heat, which are activated when the temperature rises. Consequently, they can respond to thermal stimuli detected in the surrounding environment. As a result, when the temperature rises, they increase energy consumption to adapt to temperature changes and play an important role in regulating germination and reproductive cycles at specific temperatures.

Signal Transmission

When signal transmission occurs, various substances affect it. Ca²⁺(Calcium ion) induces and regulates many physiological reactions through changes in concentration. Also, when cAMP(cyclic adenosine monophosphate) increases, it can regulate protein phosphorylation. Furthermore, cGMP(guanosine monophosphate) is involved in the intercellular signal transmission pathway. This plays a role in transmitting signals into the cell. When these various substances are involved and signals are transmitted, specific proteins are activated. For example, when desulfurization protein is activated, it helps with photosynthesis or chlorophyll synthesis.

Gene Expression

Gene expression means that among the genes in a cell, only the necessary genes are expressed to produce mRNA and protein, and most of the remaining genes are not expressed. When gene expression occurs, transcription factors promote or suppress mRNA synthesis. In addition to transcription factors, gene expression is also regulated by the stability of mRNA. This can control specific gene expression for a long time.

Stress Memory & Memory Transfer

Plants remember past stress events and use their stored responses to adapt to the environment. Short-term memory is an immediate response to the stimulation caused by initial environmental changes. For example, when there is a lack of water, the stomata are closed to minimize the water loss. Long-term memory is caused by continuous environmental changes and changes in gene expression in the long term. For example, when temperature stress continues, genes that allow the plant to adapt well to changing temperatures are expressed. When drought continues, genes that allow the plant to conserve water for a long time are expressed. In this way, plants activate genes in a favorable way. In order to evolve in such a constantly changing environment, plants continuously receive information from the environment throughout their lives and adjust their development according to favorable conditions for survival and proliferation. In addition, they continuously strengthen plants by passing on these environmental memory information to the next generation.

Example

There are two plants that can explain the memory of plants well: Mimosa pudica and the Venus flytrap. Firstly, Mimosa pudica, known for being a sensitive plant, closes the leaves within seconds when stimulated. By closing the leaves, it defends itself. If the potted plant is dropped from about 6 inches above a cushion continuously for a minute, it will gradually not close the leaves from then on. Here, the plant itself has basically realized that it would not hurt itself falling on the cushion. These memories last for about a month. Secondly, for the flytrap, its leaves have fine hairs called sensory hairs. When a fly enters the leaf and touches the sensory hair once, the plant is able to detect that something has entered the leaf. If the fly touches again within 30 seconds, the fly trap will be convinced and close the leaf. Because it uses a lot of energy to close the leaves, it has to be touched twice to close the leaves. Once a fly touches it, it can't tell whether it's food or a leaf, so it eats food like this to supplement nutrients. The actions of these plants are all done through memory.

The memory of plants plays an important role in adapting to environmental changes. Plants adapt to the changing environment by recognizing and adapting to the environment rather than being able to really remember.