Find out how plants work




Plants may seem physiologically simple compared to mammals, but they’re actually comparably sophisticated. Over millions of years, plants have evolved to live in just about every situation, not only with their own kind, but with all kinds. They thrive, despite the elements, in snow-packed alpine ranges, desert landscapes, and rocky outcrops blistering in the sun. They have been and continue to be plagued and preyed upon by insects, fungi, bacteria, viruses, birds, animals, humans, and even other plants. They, as a whole, have learned to withstand forces of Biblical proportions, like heavy winds, floods, and fires; some plants, particularly those in seed stage, have even used these climatic disasters to their advantage—spreading their progeny far and wide in the aftermath of the tumult. Now that’s far more than I can say for the human species!

Like a monk in meditation, plants are rooted to their place, but are anything but restful in their surroundings. What may be registered as “unmoving” to us is often a series of imperceptible (yet sometimes perceptible) movements and growth—aboveground, belowground, and even on a cellular level within leaves, stems, roots, and seeds. A plant’s aboveground structures, though obvious, are still subtle in their ways. Plants responsive to us, say a Mimosa pudica, or sensitive plant, whose compound leaves fold inward as we stroke them; or a Dionaea muscipula, or Venus flytrap, which triggers a trap after two strokes of its bristles within twenty seconds of one another, are strange delights for young and old alike.

A plant’s belowground structures, that is to say her roots, are even more mysterious. A dark cloak of soil or substrate surrounds the roots, propping a plant up and giving her the best supply of water, keeping her roots from becoming waterlogged. Roots and root hairs stretch and probe beneath the soil, like water witches, stealthily searching for moisture gradients. Plants are so attuned to their dark underground environment that it has even been shown that they may use acoustical vibrations—like the sound of running water—to dowse for water sources at a distance. Once they’ve detected moisture in the soil, they siphon both water and dissolved nutrients, via osmosis, from root hairs through stems and up to the crown in a process known as “ascent of sap.” It’s the dissolved nutrients—or cations—like magnesium, phosphorus, and nitrogen that become part of the plant tissue and aid the plant in important life functions like enzyme production and metabolism. These nutritious benefits are then bestowed onto those who eat plants, including humans. And yet, many humans have never noticed these life-giving benefits, but perhaps we’ll feel more grateful for them the next time we eat our vegetables.

Plants are the connective tissue between earth and sky. As water makes its way up through the plant, it exits the leaves, and in some cases the stems, through small lips-shaped pores called stomata; this process is called transpiration. This gaseous exhalation from the leaves creates humidity in the surrounding atmosphere—both indoors and out—and fuels the water cycle, which indigenous peoples of the Amazon describe as “rivers in the sky.” This moisture eventually gathers in clouds and falls to earth again, ensuring that plants of all kinds have a reliable source of water.

The stomata also create a pathway for both carbon dioxide and oxygen to pass freely into and out of the plant. As CO2 comes in, the carbon is cleaved by light energy and combines with water to yield carbohydrates, oxygen, and residual water. The light energy that fuels this whole process is captured by the green part of the plant—the chlorophyll—which is found in the leaves and stems. A plant’s leaves are intricately and efficiently designed to consume light, acting like giant solar panels that can track the sun’s movements throughout the day and over time, giving the plant a reliable energy source to fuel itself—and to fuel the world. In the winter months or dry seasons, when many plants go dormant, they shuttle the carbohydrates down through the stem to be stored in their roots and modified root systems like tubers, corms, bulbs, and rhizomes. When springtime or the rainy season comes, the plants can pull the carbohydrate stores up again, which is why we can tap maples for syrup in spring and sweet potatoes can generate such prolific green growth from their tubers on our kitchen counters.

As you begin to appreciate the subtleties of plants, not only will you learn about how to care for them but you’ll also begin to consider the pace of their lives. Plants are slow, quiet, and, most of all, complex creatures. As you bring them into your life, I encourage you to match their disposition when you can. By developing this sensitivity toward plants, you may find that the more you give to plants, the more you gain. With practice, it’ll start to come naturally:

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