33.2 recap

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33.2 recap

The three concentric tissue systems of the plant embryo—dermal, ground, and vascular—give rise to the tissues and organs of the adult plant. These tissue systems have unique combinations of specialized cells that carry out the various functions necessary for plant life.

learning outcomes

You should be able to:

  • List and discuss the importance of the various functions of parenchyma.

  • Define cell characteristics that make collenchyma useful as plant support structures.

  • Compare collenchyma and sclerenchyma in terms of their ability to provide support to plants.

  • Describe the water-conducting elements in plants, and compare these elements in gymnosperms and angiosperms.

Question 1

Create a table comparing the three types of ground tissue cell types in terms of their structure and function.


Tissue Structure Function
Parenchyma Thin-walled, large vacuoles Photosynthesis in leaves, storage in roots
Collenchyma Elongated, thick-walled at corners Flexible support in petioles and stems
Sclerenchyma Thick-walled, bundles Support of stems, occurs in fruits

Question 2

What structural differences make tissues consisting of collenchyma cells more flexible than those consisting primarily of sclerenchyma cells?

Collenchyma has primary walls at the corners of cells and is somewhat flexible; sclerenchyma has thick, less-flexible secondary walls.

Question 3

Describe the differences between tracheids and vessel elements.

When tracheids die, pits in their walls remain and allow water to flow between the cells. Vessel elements are long tubes, laid end-to-end, that die and form a continuous tube.

After the plant embryo has formed, it is encased in a seed coat and is ready to germinate. We will discuss aspects of seed germination in the chapters that follow. For now, let’s consider the processes by which the embryo grows into a mature plant.