Asexual Propagation

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Published June 14, 2012 | Updated September 20, 2013
Subject: Science
Place of Learning: Garden Classrooms
Resource Type: Lessons
Grade Level: Grade 7
Uploaded by:
Kyle Cornforth
Program Affiliations:

In this 7th grade science lesson, students identify desirable traits in plants and take cuttings from parent plants to facilitate asexual propagation and produce offspring with identical DNA.

Objectives

After this lesson, students will be able to:

  • Explain why plants are reproduced asexually
  • Understand that asexual offspring are genetically identical to the mother plant
  • Use cuttings to propagate perennial plants asexually
Assessments

During this lesson, students will:

  • Identify three reasons for reproducing plants asexually in the garden
  • Identify the cutting as genetically identical to the mother plant
  • Successfully propagate a plant asexually
Materials
  • Wooden flat of growing medium (we use perlite)
  • Perennial plants with branches available for cutting
  • Examples of a rooted cutting and a mature, potted up cutting
  • Visual aid
Preparation

Before You Begin

  • Collect and prepare all the materials
  • Create the visual aid
Procedures

At the Opening Circle

  1. Welcome students and introduce this asexual propagation lesson as an extension of their science class lessons on genetics.
  2. Tell students they will participate in asexual propagation, cloning plants by taking cuttings from mother plants and reproducing them.
  3. Ask students to share what they know about how plants typically reproduce. Differentiate between generating plants through sowing seeds (sexual reproduction) and today’s activity, which reproduces the traits and genetic material of the parent plant asexually.
  4. Ask students why a grower would choose to use asexual propagation. Discuss with students that there are three main reasons. It is faster than propagating by seed, you can select desirable traits, and it is cost effective.
  5. Ask students what traits a grower would want to preserve through asexual reproduction. Some examples are color of flower, high productivity, and good health.
  6. Demonstrate how to take a cutting from the mother plant. Point out the importance of exposing the nodes, trimming the upper leaves, and placing the cutting at a 45-degree angle in the growing medium.
  7. Show students an example of a rooted cutting and a mature, potted up cutting.
  8. Tell students that they will be having a tasting during Closing Circle.
  9. Divide students into working groups. During their garden jobs, students will take a break to take an asexual cutting from a perennial plant.

In the Field

  1. Gather students around a perennial plant and review the directions for taking a cutting from the visual aid.
  2. Have each student take a cutting of the perennial plant, expose the nodes and trim the upper leaves.
  3. Once all students have taken a cutting, have each one place their cutting in the wooden flat at a 45-degree angle, label it, and have one student water the flat when everyone is finished.
  4. As students are preparing their cuttings, ask them the following questions.
  5. Why do we use asexual propagation? (it is faster than seed, we can select traits, it is cost effective)
  6. Are these cuttings genetically identical to the mother plant? (yes!)
  7. Why is it important to expose the nodes? (because leaves underground could cause the plant to rot)
  8. Why do we clip off the upper leaves on a cutting? (to minimize transpiration and help keep the plant moist)

At the Closing Circle
Have a few students serve a seasonal tasting harvested and prepared as part of their working group's garden job.

Vocabulary

Perennial
Perlite
Cutting
Strike
Sexual propagation
Asexual propagation
Genotype
Phenotype
Traits
DNA 

Connections to Standards

California State, Science, Grade 7
7.2.a. Students know the differences between the life cycles and reproduction methods of sexual and asexual organisms.

Edible Schoolyard in the Garden, Propagation, Grade 7
7.4 Students practice asexual propagation including cuttings and grafting. 

Contributors

All lessons at the Edible Schoolyard Berkeley are a collaboration between the teachers and staff of the Edible Schoolyard and Martin Luther King Jr. Middle School. 

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