Whispers Beneath: The Secret Life of Plants

Imagine a hidden world, teeming with clandestine chatter and strategic
alliances—except this is not a secret society of humans, but a sprawling network of
plants. Beneath our feet lies a bustling, dynamic system where flora communicate,
negotiate, and collaborate in ways that are as complex and intriguing as any human
interaction. Welcome to the subterranean realm of plant communication.

The Mycorrhizal Web: Nature’s Undercover Network
Forget the notion of plants as passive green ornaments. In the soil, they’re anything but
silent. The foundation of their covert operations is the mycorrhizal network—an
elaborate fungal web that connects roots across species and generations. Think of it as
nature’s internet, where mycorrhizal fungi form intimate partnerships with plant roots,
creating an underground exchange network. This fungal mycelium not only facilitates
nutrient transfers but also serves as a conduit for communication between plants.

Imagine a plant under attack by pests. Instead of sending a distress call via email, it
sends out chemical signals through this fungal network. Neighbors pick up these signals
and ready themselves for a potential assault. It’s like receiving a warning from a friend
about an impending storm so you can batten down the hatches.

The Symphony of Signals
Plants don’t have brains or nervous systems like animals, so their communication is less
like a conversation and more like an intricate system of plumbing. When a plant’s roots
sense a drought, they can send electrical signals through their vascular system—akin to
sending an urgent text message—to their leaves, instructing them to cut back on water
loss. This electrical communication can be monitored by placing electrodes on different
parts of a plant, translating these signals into sounds that reveal the plant’s hidden
dialogues.

Yet, the drama doesn’t stop at electrical impulses. Plants also release volatile chemicals
into the air and soil. These “volatiles” are like a plant’s personal fragrance, carrying
crucial information about their status. For example, when grass is mowed, it releases a
mix of chemicals that signals distress, attracting predators that might feast on the
herbivores causing the damage. It’s a bit like sending out a call for help, with a hint of
“please come to my rescue.”

The Underground Choir: Fungus and Friends
While plants might be busy sending chemical signals and electrical impulses, they’re
also engaging in complex partnerships with fungi and microbes. These relationships are
far from superficial. Plants release root exudates—chemical compounds that fungi and
soil microbes interpret as invitations or warnings.

Fungi, in return, offer essential nutrients, acting as the plant’s underground suppliers.
This mutualistic relationship often extends to a larger network of trees and plants
connected through a single fungus, creating an interlinked community of flora. For
instance, older trees, known as “nurse” trees, can share carbon through these fungal
networks with younger, less photosynthetically active trees, ensuring the survival of the
forest’s younger generation. It’s a living testament to cooperation and support in
nature’s own social network.

From Ultrasonic Whispers to Volatile Exclamations
Recent studies have uncovered another layer of plant communication: ultrasonic
sounds. Just as you might hear a stressed friend through a phone call, plants emit
high-frequency sounds when they’re under stress. These sounds, imperceptible to the
human ear but audible to some insects and mammals, are part of the plant’s distress
signals. For instance, tomatoes and cacti have been recorded emitting ultrasonic
popping sounds, which could be a way to attract help from insects or warn nearby
plants

This phenomenon is particularly fascinating because it opens new avenues for plant
diagnostics. Scientists are developing ways to use these ultrasonic emissions to monitor
plant health without physical contact, a bit like having a remote sensing device that
listens to the plant’s needs.

Smells Like Trouble: Chemical Communications
Not all plant communication is subtle. Plants also use volatile organic compounds
(VOCs) as airborne signals. These chemicals can be a plant’s version of shouting across
the neighborhood, sending out alarm signals or attracting pollinators. When a plant is
under attack, it might release VOCs that not only warn other plants but also attract
predators that will feast on the attackers.

Interestingly, plants can distinguish between their own kin and strangers through these
chemical signals. They’re able to recognize and preferentially support their offspring, a
strategic maneuver to ensure the survival of their genetic lineage. This kin recognition
is akin to a family loyalty pledge in the plant world.

The Future of Plant Communication
Understanding these underground conversations has profound implications for
agriculture and environmental conservation. By decoding plant signals and improving
soil health through better management of the mycorrhizal networks, we can enhance
crop yields, combat climate change, and restore damaged ecosystems. The more we
learn about this hidden world, the better equipped we’ll be to support and sustain our
green companions.

So, the next time you walk through a forest or garden, remember that beneath the
surface, there’s a vibrant, communicative world at work. Plants might not speak in
words, but their signals, scents, and sounds create a rich tapestry of interaction that
ensures the survival and thriving of life above ground.

written by Yeshra Rahman