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The appeal of pratical classes

There is so much valuable information in this gorgeous image that it can provide enough content from Middle School lessons to College lectures. This one in particular was used in Anatomy and Plant Morphology practical classes in a Biological Sciences Program.

The biological structures in their natural state can fascinate learners, exciting both their attention and interest. I have always believed that images are essential to learning.

What can we see in this image?

These are the abaxial epidermal cells (lower surface) in a Tradescantia pallida purpurea leaf under light microscopy.

Useful information for student discussions:

- "The primary function of the epidermis to provide coating. The compact arrangement of cells prevents both the action of mechanical shocks and the invasion of pathogens while also limiting the loss of water." Also worth mentioning are the gas exchanges through the stomata. Stomata consist of two cells (guard cells) delimiting a cleft in the central region (ostiole), through which the communication between the interior of the organ and the external environment takes place.

- In this image we can observe a tetracytic-type stomate, which is surrounded by four subsidiary cells. Two of them are parallel to guard cells while the remaining polar pair is often smaller." These tiny green blobs are chloroplasts.

- Some cells have a pink coloration, named anthocyanins, a product of plant secondary metabolism. The term originates from Greek (anthos = flower; kyanos = dark blue). They are water-soluble phenolic substances deposited inside vacuoles, acting as both antioxidants and a protection against solar radiation.

- In addition, these "needles" we can see represent inclusions of calcium oxalate, in the form of raphides. They have also built up inside vacuoles.

O texto revisado em inglês foi realizado em parceria com a Adept (

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