The Light Eaters: How the Unseen World of Plant Intelligence Offers a New Understanding of Life on Earth

by Zoë Schlanger

As photons from the sun fall upon a plant’s outstretched green parts, chloroplasts in the leaf cell convert the particle of light into chemical energy. This solar power gets stored inside specialized energy-storing molecules, the rechargeable battery packs of the plant world. At the same time, the leaf siphons carbon dioxide out of the air through minuscule pore-like openings on the underside of the leaf, called stomata. Under a microscope, stomata look like small parted mouths, fish lips that open and close. They are breathing, after all, in their way. The stomata suck in carbon dioxide, and the carbon dioxide now encounters both the stored solar energy in the chloroplast and the water that is coursing, always, through the leaf’s veins. Through that encounter with the pure energy of light, the water and carbon dioxide molecules are ripped apart. Half of the oxygen molecules from both parties float away from this meeting, passing back out into the world through the parted lips of the stomata—becoming the air we breathe. The carbon, hydrogen, and oxygen that remains is spun into strands of sugary glucose. To be precise, it takes six molecules of carbon dioxide and six molecules of water, torn apart by power from the sun, to form six molecules of oxygen and—the true aim of this whole process—one precious molecule of glucose. The plant uses the glucose to build new leaves, which will be used to make more glucose. It also shuttles the glucose down through its body, passing it ...