Plant Communication

Cell communication in plants

As a starting point, let's take a look at the structure of plant cells. Remember that plants are a part of the kingdom Plantae and the domain Eukarya.

Although plant and animal cells have some similarities, plant cells have some structures that animal cells don't.

• Plant cells have a cell wall of cellulose that gives the cell support.

• They also have a central vacuole containing a weak solution of sugars and salts. The central vacuole is used for storage, waste breakdown, and also aids in metabolism. The tonoplast is the membrane enclosing the central vacuole.

• Chloroplasts are photosynthetic organelles that contain chlorophyll for photosynthesis.

• Plasmodesmata are channels that connect adjacent cells' cytoplasm through the cell wall and plasma membrane.

Plants can communicate in various ways, such as through direct contact, plant hormones, and electrical signaling. Different activities are coordinated based on environmental stimuli through communication.

These junctions called plasmodesmata between plant cells are where cellular communication takes place through direct contact (cell-to-cell contact). The plasmodesmata transport materials from cell to cell through the cytoplasm.

Local signaling in plants

Although there is a lot that researchers still do not understand about local signaling in plants, they do know that just like animals, plants can use hormones for signaling. Most plant hormones reach their target cells by moving cell-to-cell.

• A target cell is any cell that has a receptor for the hormone.

Some important plant hormones include:

• Auxin (IAA) - Stimulates stem elongation, root growth, and branching. It also regulates fruit development and enhances functions in phototropism and gravitropism.
• Cytokinin - Stimulates cell growth, cell division, and germination.
• Gibberellins - Promotes seed and bus germination, shoot elongation, and leaf growth. It also promotes flowering and fruit maturation.
• Ethylene - Promotes fruit ripening and leaf fall.

Plant communication electrical signaling

As a response to environmental stimuli or hormones, plants generate electrical signals as a form of communication. These signals affect plants in different forms, including photosynthesis, respiration, flowering, and wound healing.

Step 1: Reception - The first stage of signal transduction in plants is reception. Here, signals such as hormones (chemical signals) or environmental stimuli are detected by receptors usually located in the plasma membrane. These receptors are proteins that change in shape in response to a specific stimulus.

Step 2: Transduction - Following the reception of the signal, transduction occurs. The transduction of these signals involves second messengers.

Step 3: Response - When second messengers transfer the signal to proteins that produce a physiological and cellular response.

Plants communicate through roots

Scientists have viewed plants very differently ever since one research changed the way they thought about them. It has been discovered that plants are capable of communicating through their roots! They do this by secreting root exudates into the soil through the rhizosphere (the plant's root zone).

This form of communication is the primary way in which plants communicate with their rhizosphere microbiome to facilitate nutrient absorption, plant-to-plant signaling, the recruitment of beneficial microorganisms and even parasitism!

Do plants have any help when it comes to communicating with other plants? The answer to this question is yes! Plant communication can be enhanced by the presence of mycorrhizal fungi.

These mycorrhizal fungi contain big mycelial networks that are very efficient in transmitting signals between the roots of plants, and also help the plant's root to acquire water and minerals from the soil.

• A mycelium is an interwoven network of hyphae (thread-like structures that comprise the vegetative body of the fungus) used for nutrient absorption.

Plant communication examples

Let's look at examples of how plants use communication to respond to different environmental stimuli.

In drought seasons, plant cells communicate with other plant cells to reduce the rate of transpiration and conserve water. This is done by the release of abscisic acid (a plant hormone) in the leaves, which helps keep a plant's stomata closed.

Some plants can communicate through impulses known as action potentials.

Figure 6. Venus flytrap.

During cold conditions, plants might respond by adjusting membrane fluidity and producing antifreeze proteins. On the other hand, a plant can respond to severe heat stress by producing heat-shock proteins that reduce protein denaturation.

Plant communication impact factor

One of the most popular journals regarding plant biology is called plant communications. This journal publishes research involving technical advances and resources in plant evolution, ecology, plant physiology, plant biochemistry and many other areas of plant biology.

Plant communication research

To finish off, let's explore some interesting research on plant communication. Researchers have found that elevated levels of ozone (O₃) cause disruption in the communication between plants and insects in urban areas by degrading volatiles involved in the communication.

Another research found that melon plants that have been infected by a type of potyvirus (watermelon mosaic virus) are able to emit volatiles that induces gene deregulation in healthy plants nearby, similar to preparing them for incoming infections!