Lesson plan

Plant Structures and their Functions

A caption reveals important information to a reader. Use this lesson with your students to teach them about plant structures and their functions, while they learn how to be a text feature author.
GradeSubjectView aligned standards

Students will be able to create captions that describe the function of plant structures.

(3 minutes)
Name the Parts of a Plant
  • Show students a page from an informational text that contains a photograph and a caption. Point to the caption and ask students to identify the name of the text feature and its purpose.
  • Tell students that a CaptionIs a text feature that gives information about an illustration or photograph.
  • Explain that today’s lesson will give the class the opportunity to become caption writers as they learn about plant structures and their functions.
  • Guide students in a choral read of the learning objective.
(10 minutes)
  • Explain that the StructureOf the plant is the way that it is built. It has certain parts and they each have a Function, or a specific job. The structures include the root, stem, leaves, bud, and flower.
  • Describe the structures of the plant and explain the function of each. Display the definitions on a word wall or an anchor chart:
    • The RootsSupport the plant and absorb water and nutrients from the ground.
    • The StemCarries the water and nutrients from the roots to the leaves. It also supports the leaves, bud, and flowers.
    • The LeavesMake the food for the plant through a process called photosynthesis. The leaves are the “food factory” in the plant.
    • The BudDevelops flowers.
    • The FlowersAre responsible for making new seeds, which allows for new plant growth.
  • Share that you will model how to write a caption with a diagram about volcanoes. Display the Structure of a Volcano image and model how to write a caption for the magma chamber. For example, "The magma chamber is the large pool of liquid rock beneath the earth’s surface. It holds the magma underneath the ground until a volcanic eruption."
  • Explain that today’s lesson will focus on creating captions for a diagram of a plant. The information about the key terms will be useful in creating captions.
(10 minutes)
  • Distribute a copy of the Name the Parts of a Plant worksheet and five sticky notes to each student. Label the diagram together as a class.
  • Model writing a caption for the root. For example, "The root is underground and supports the plant by absorbing water and nutrients from the ground." Have students copy this caption on one of the sticky notes and place it on the diagram near the roots.
  • Put students into small groups of three to four students. Have them collaborate to write a caption for the stem on a whiteboard. Remind groups that they can reference the definitions of the key terms, but that the caption must be in their own words. Circulate and offer guidance and feedback as needed.
  • Call on nonvolunteers to share the caption created by their group, and pull phrases and wording from the different examples to create one for the whole class to use. Direct students to record the collaborative caption on one of their sticky notes.
(15 minutes)
  • Instruct learners to write captions for the remaining plant structures on sticky notes. Remind them to keep the focus of the caption on the structure’s function.


  • Provide sentence frames for students as they write the captions. For example, "The job of the ____Is to ____."
  • Give students a copy of the definitions for the plant structures for easy reference.


  • Have advanced learners research the structures of a plant in more depth. Challenge them to create a book with illustrations, diagrams, captions, and other important information about each plant structure to share with the class.
(5 minutes)
  • Put students into A-B partnerships, and have each student share the captions they wrote. Challenge them to provide feedback to each other and ask clarifying questions if necessary.
  • Observe partner discussions and listen for correct explanations to serve as a formative assessment of students’ understanding of plant structures and their functions. Listen for complete sentences that make sense to serve as an assessment of students’ understanding of how to write a caption.
(2 minutes)
  • Ask the class to think about how a plant is like the community. Elicit answers that lead them to the conclusion that structures of a plant work together to keep it alive, while structures in a community work together to keep it thriving.
  • Point out that each structure of the plant has an important function in order for it to survive.

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