Exploring the Wonders of Stem Structure

Exploring the Wonders of Stem Structure

Learning Objective

At the end of the lesson, you will be able to understand the importance of stem structure in horticulture and explain the functions of different parts of a stem.

What do you already know about the structure of plant stems?

Importance of Stem in Horticulture

The stem plays a crucial role in providing support, transporting water and nutrients, and storing food in plants.

Parts of a Stem

A stem consists of several parts: xylem, phloem, cambium, pith, and epidermis

Xylem and Phloem

Xylem is responsible for transporting water and minerals from the roots to the rest of the plant, while phloem carries sugars and other nutrients.

https://www.saps.org.uk/teaching-resources/resources/1299/biology-animations-transport-of-water-and-sugar-respiration-and-photosynthesis-and-cell-growth-in-plants/

Cambium, Pith, and Epidermis

Cambium is a layer of actively dividing cells that allows for secondary growth, pith stores food and provides structural support, and epidermis acts as a protective outer

Transpiration and Its Importance

Transpiration is the process of water movement through a plant and its evaporation from aerial parts. It helps in nutrient uptake and cooling, but excessive transpiration can lead to water loss.

Reducing Transpiration during Cuttings

When taking cuttings, it is important to reduce transpiration to prevent excessive water loss and ensure successful propagation.

Types of Stem Cutting

There are different types of stem cutting methods used in horticulture, such as tip cuttings, nodal cuttings, and heel cuttings. Each method has its own advantages and is suitable for specific plants.

Why do we take stem cuttings?

1. To propagate new plants with the ability to develop roots.
2. To increase the lifespan of the plant.
3. To prevent the spread of plant diseases.
4. To enhance the plant's ability to absorb nutrients.

What is transpiration?

1. The process of water loss through the plant leaves.
2. The tissue responsible for reproducing in a plant.
3. The movement of water from the roots to the leaves.
4. The process of converting carbon dioxide into oxygen.

What is the cambium for?

1. The process of converting sunlight into chemical energy.
2. The outer protective layer of the plant root.
3. The tissue responsible for storing water in a plant.
4. The cambium is responsible for secondary growth, producing new xylem and phloem cells.

What is the phloem?

1. The innermost layer of cells in the plant root.
2. The process of water absorption by the plant roots.
3. The tissue responsible for producing flowers in a plant.
4. The tissue responsible for transporting sugars and other organic compounds in a plant.

What is the xylem?

1. The tissue responsible for transporting water and nutrients in a plant.
2. The tissue responsible for photosynthesis in a plant.
3. The process of water loss through the plant leaves.
4. The outer protective layer of a plant stem.

Activity: Identifying stem Cuttings

In this activity, you will identify different stem cuttings and their purposes. Look closely at the stem structure and think about how each cutting can be used for propagation.

internodal cuttings

soft wood cuttings

hardwood cuttings 

Linking Propagation Techniques

Let's connect the dots! How do propagation techniques like lamina leaf cuttings and petiole cuttings relate to what we've learned about stem structure? Discuss and share your thoughts.

How do propagation techniques like lamina leaf cuttings and petiole cuttings relate to what we've learned about stem structure?

Lesson Reflection

Take a moment to reflect on the purpose of this lesson. Why is understanding stem structure and its role in horticulture beneficial to your knowledge as future horticulturists?

Write down 3 things you learned in this lesson.

Have students enter three things they learned in this lesson. With this they can indicate their own learning efficiency of this lesson.

Write down 2 things you want to know more about.

Here, students enter two things they would like to know more about. This not only increases involvement, but also gives them more ownership.

Ask 1 question about something you haven't quite understood yet.

The students indicate here (in question form) with which part of the material they still have difficulty. For the teacher, this not only provides insight into the extent to which the students understand/master the material, but also a good starting point for the next lesson.