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Lesson 9 Multicellular Organisms

  Plant Tissues

Each plant system is made up of tissues that help the system perform its functions.



Most of these tissues are present in both systems, but they have slightly different functions depending on the system.

A9.11 Water Lilly stem
The dermal tissue is also called the epidermis, and it is the outer layer of cells on all parts of the plants. It is very similar to skin cells in animals. This tissue is normally one cell layer thick, and it has a variety of functions. In woody plants such as trees, the epidermis is the bark. In the shoot system, it

  • protects the plants from disease
  • produces a substance called the cuticle that helps to stop microorganisms from damaging the plant and prevents water loss
  • allows oxygen and carbon dioxide to move into and out of the plant through the stem and leaves

In the root system, the dermal tissue is responsible for allowing water and nutrients into the cells.

A9.12 Water lilly stem
This is the layer below the dermal tissue. It makes up most of the plant and has several important functions. In the shoot system, it

  • provides strength and support to the plant
  • is the location of photosynthesis

In the root system, it plays an important part in food and water storage.

The ground tissue is made up of many loosely packed cells. It is important that the cells are loosely packed as that creates space between each cell. This space allows for the quick diffusion of gases such as carbon dioxide and oxygen.

A9.13 Water Lilly stem
A vascular tissue is in charge of transporting materials throughout the plant. The xylem vascular tissue is specifically for moving water and dissolved minerals from the roots to the leaves. Each xylem tissue cell starts out as living but is dead by the time it is part of this tissue. The living cells are shaped like small straws and stack up end to end. As they grow, the ends of the cells start to break down, killing the cell. The sides then fuse together and a long tube is created.

A9.14 Water lilly stem
The phloem tissue works in a different direction to the xylem. While the xylem transports in one direction, the phloem can transport in many different directions. It takes the sugars that are created through photosynthesis in the leaves and transports them to the rest of the plant. The cells in this tissue are also tube-like in structure, but they remain alive. The ends of the cells have little holes in them to allow for the movement of sugars down the tubes and out into the plant tissues. The cytoplasm of these cells leaks out of the ends and creates a passageway from one to the next.

The sugars that are transported by the phloem tissue can be used by the cells or stored in the leaves, stem, or roots of the plant.


A9.10 Root and shoot system

  Read This

Please read pages 299 and 300 in your Science 10 textbook. Make sure you take notes on your readings to study from later. You should focus on the different tissues and their functions. Remember, if you have any questions or you do not understand something, ask your teacher!

  Practice Questions

Complete the following practice questions to check your understanding of the concept you just learned. Make sure you write complete answers to the practice questions in your notes. After you have checked your answers, make corrections to your responses (where necessary) to study from.

  1. Complete the chart below about the different plant tissues.

    Tissue Function in Shoot System
    		Function in Root System
    		Location in Plant
    Dermal
    Ground
    Xylem
    Phloem


Tissue Function in Shoot System
Function in Root System
Location in Plant
Dermal
  • protects the plants from disease
  • produces a substance called cuticle that helps to stop microorganisms from damaging the plant and prevents water loss
  • allows oxygen and carbon dioxide to move into and out of the plant through the stem and leaves
  • responsible for allowing water and nutrients into the cells
surface of plant
Ground
  • provides strength and support to the plant
  • is the location of photosynthesis
  • food and water storage
 under the epidermis
Xylem
  • moving water and dissolved minerals from the roots to the leaves
  • moving water and dissolved minerals from the roots to the leaves
 within the ground tissue
Phloem
  • moving sugars from leaves to the rest of the plant, especially to areas where the plant is growing
  • moving sugars from leaves to roots
 within the ground tissue