Do you relish the opportunity to read plant names aloud? Do you find watching videos about plants and how to care for them a good way to spend an afternoon? Was the middle school Biology unit about plants kinda your jam? You’re in luck! Today we’re lightly dipping into plant anatomy, the division of Botany that studies the parts of plants that make up the whole. Ready? Let’s get geeky!
Plant parts can be lumped into the two main categories of roots and shoots, or what grows up and what grows down. The three most very basic parts of a plant are roots, stems, and leaves. But that’s a little like saying humans are just a trunk, head, and appendages. There are other parts of plants that perform a variety of functions including flowers that help make more plants. Pollen plus germ cell equals seed and so on and so forth.
Roots anchor a plant and help it remain upright. Roots also absorb water and nutrients and may grow down, attach to and climb up walls or other surfaces, and may even float in the case of some water plants. Fibrous roots pull in water and nutrients from their surroundings, whether that be soil, water, or in the case of epiphytes (plants, such as Monstera, that grow on the sides of trees or other structures) the air.
One special type of root is a tap root. This root grows thick and wide at the top and tapers as it shoots straight down deep into the soil. Tap roots do an excellent job of anchoring a plant and sourcing water deep underground. The underappreciated, resilient dandelion also has a taproot, which is why it’s so hard to pull out of the ground.
The shoot is the part growing above ground and includes the stalk or main stem, other stems, leaves, and all additional plant parts. The stalk, or stem, help hold up the plant and encapsulate the vascular system, xylem and phloem (nope, not a disease but a type of plant cell),which moves water, food, and nutrients through and to plant parts. Plant cells become rigid when filled with water. Wilting is often the result of cells that are depleted of water and beginning to collapse.
What about what’s attached to the stalk? The point at which a leaf stem connects to the shoot is called a node, and the stretch of stalk or stem between nodes are internodes. The small stem between the leaf and the stalk is called a petiole. So, from stalk, to node, to petiole, to leaf. Got it?
What’s up with leaves? Leaves are a specialized plant part that serves to convert energy from sunlight into food for the plant. Not all leaves are created equal, however, and not all leaves are leaves. Seed leaves, or cotyledons are the first set of leaves to emerge upon germination and look nothing like the plants actual leaves. True leaves emerge next and will look like the familiar leaves of the plant you’re growing.
Many modified leaves also exist. Those spines on a cactus? Those are leaves too. And photosynthesis is actually carried out by the large, fleshy body of the cactus rather than the leaves, as is the case with many other plants.
That pretty, colorful part on poinsettias? Those aren’t flowers, those are modified leaves called bracts. The blooms are tiny little things nestled in the bracts are called cyathia. That is where the pollen lives.
Flowers are pretty, many even smell nice, and we humans certainly enjoy them. But, they serve a much more noble purpose than existing solely for our pleasure. Flowers exist to help plants make more plants. This really is a story of the birds and bees. Nectar is an energy source for pollinators. Flowers create nectar to attract pollinators, but for the plant’s purpose, what it really needs is a way to move pollen around. Pollinators inadvertently do this as they visit flower after flower to collect nectar. Oh, those smarty plants! They can’t move about and visit each other, so they get the bugs, the birds, even mammals, and the wind to do it for them.
Flower shape plays and important role. Flowers are attractive to different pollinators for different reasons. The wide, open petals of a coneflower serve as a landing pad and make it easy for bees and butterflies to collect nectar. Hummingbirds like tubular shaped flowers. They are able to insert their long beaks as they hover in flight. Flower color matters, sometimes. Hummingbirds really are attracted to the color red, but they’ll find other flowers they like that aren’t red, too.
Food For Thought
So how do all these parts work together to help a plant survive and thrive? Parts of a plant (usually the leaves) harness energy from the sun in a green photosynthetic pigment called chlorophyll. This plus water and carbon dioxide are converted into sugars and other compounds that will be used by the plant to fuel it’s activities, such as growing. Humans eat food for fuel, plants eat light.
These basics are just a start to understanding how your plants do all the cool things they do. Happy growing!