Lesson Plan - Get It!
Just like buildings have different structures (e.g., foundation, plumbing, windows), plants have different parts. What structure do you think is most important in plant growth?
As you have learned in the first lesson of our Plants series, found under Related Lessons in the right-hand sidebar, there are many types of plants on Earth.
Some have specialized tissues for moving water and nutrients, while others stay low to the ground to absorb water and nutrients. In this lesson, we will learn more about plant structures that help vascular plants function. Remember, vascular plants are able to grow up from Earth's surface because they have a xylem and phloem for moving materials throughout the plant.
Plants get most of their required water and nutrients from the surrounding soil. They soak up these materials with roots. Roots extend from the bottom of the plant, and can branch in many directions to try to collect as much water and food as possible.
Roots of trees and large plants go deeper than roots of grasses or mosses. Some vegetables grow from roots, like carrots and jicama, a starchy root vegetable. Potatoes and yams are called "tubers," and are specialized structures that grow off roots that are responsible for storing food for the plant.
Roots have a very special region called the "apical meristem." This region is responsible for telling plant cells to divide. When plant cells divide, the plant grows! Another unique cell found in roots are root hairs. These cells look like small hairs extending off the root tip, and can make the root look fuzzy, as shown in the image below:
Image, via Wikimedia Commons, extracted by Monedula from an image in "The New Student's Reference Work" edited by Chandler B. Beach and Frank Morton McMurry. Both images are in the public domain.
Each small root hair increases the plant area responsible for collecting and transporting water and nutrients through the plant. Roots can extend above ground, but once the plant emerges from the soil we generally call it a stem. The stem is the central part of the plant that includes both the trunk and branches. Not all plants have a trunk, but large trees can have very thick trunks.
Branches are the parts of the plant that extend out from the trunk and contain leaves. Leaves are responsible for carrying out photosynthesis for the plant. Leaves are able to produce energy for the plant because of the vascular tissues xylem and phloem that carry water and nutrients up from the soil. New branches originate from nodes located on the stem that eventually grow into axillary buds, or structures where new branches can develop.
Plants have interesting structures that allow them to grow tall and wide. While not all plants grow as large as a redwood tree, vascular plants share some common characteristics, like roots, stems, and leaves. Roots and stems are critical for plant growth.
- How might the structure of these plant parts influence their function in the plant?
- What do you think would happen to a plant if it lost one of these structures?
Discuss what you have learned about plant structures with a parent or teacher before moving on to the Got It? section, where you will review the relationship between structure and function.