The Hydraulic System: The ‘Vascular System’ of Plants

A plant’s hydraulic system is comparable to a human’s vascular system. Not only that, but plants also possess other similarities to other living species on Earth.

| March 2015

  • Plants Hydraulic System
    Communication is important to every living being, but plants’ abilities to communicate both internally and externally is different from mobile beings.
    Photo by Fotolia/anake
  • Stomata Structure
    The structure of a stomata: the surface of a plant’s leaves take in carbon dioxide and give off water vapor though these small openings on the surface.
    Illustration courtesy Island Press
  • Stomata Light Cycle
    A stomata’s cycle of opening and closing is controlled and influenced by the presence and intensity of light.
    Illustration courtesy Island Press
  • Brilliant Green
    Leading scientist Stefano Mancuso and journalist Alessandro Viola present a new paradigm in the understanding of the vegetal world in “Brilliant Green.”
    Cover courtesy Island Press

  • Plants Hydraulic System
  • Stomata Structure
  • Stomata Light Cycle
  • Brilliant Green

Are plants intelligent? Discoveries over the past 50 years have challenged the previous idea that plants are unthinking and inert. In Brilliant Green, scientist Stefano Mancuso and journalist Alessandra Viola argue that plants process information, sleep, remember, and signal to one another — showing that they are far from passive machines. This excerpt, from chapter 4, “Communication in Plants,” discusses the role that a plant’s hydraulic system has while communicating, both with itself and with other plants.

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Communication Inside of Plants

Imagine a planet where plants have learned to communicate. In this imaginary world they can exchange information and even make themselves understood by animals, including the most complex animals, humans. On this planet, plants have learned to “speak” with animals in their language and can argue persuasively to get the help they need.

They use an information network of other plants and certain animals to extend the reach of their explorations beyond their own organism. They know how to obtain small services and, when necessary, intervention from other species, especially when, unable to change their location, they must defend themselves from herbivorous predators. They also get help with reproducing and propagating themselves in the environment.



Can you imagine such a world, where the most silent, passive, and defenseless organisms we know—plants—influence, and in some ways orchestrate, the lives of animals, from the smallest root worm to human beings? This world already exists: welcome to Earth.

Transmitting Messages Inside Plants

Does a plant communicate within itself? First let’s ask a different question: How would having this capacity be useful to a plant? Trying to answer this will help us understand the roots’ ability to communicate with the leaves, and vice versa.