Plant tissues in a stem section
Look at a stained cross-section of a sunflower stem and label the epidermis, cortex, phloem, cambium, xylem and pith.
Core concept
A dicot stem has protective, storage, transport and growing tissues; xylem carries water up and phloem carries food, arranged in a ring of vascular bundles
Topic: Plant tissues
A tissue is a group of similar cell: The tiny building block that every living thing is made of. All key words doing the same job. In a cross-section of a young dicot stem such as sunflower, the outer epidermis is a single protective layer of cells. Inside it is the cortex, made of loosely packed parenchyma cells that store food. A ring of vascular bundles carries materials: in each bundle, phloem on the outside carries food, xylem on the inside, with its wide empty vessels, carries water and minerals up from the roots, and between them a thin layer of cambium divides to make new xylem and phloem so the stem grows thicker. The soft pith in the centre stores food.
What you will learn
- Identify the main tissues in a stem section.
- Describe the function of each tissue.
- Explain how water and food travel through a plant.
Before you start
- Know that plants are made of cells.
Materials
- Prepared stained section of a sunflower stem
Equipment
- Compound microscope
Procedure
- Look at a stained, prepared section of a young sunflower stem under the microscope.
- Choose a tissue card, find out what it does, and place it on the matching letter.