stem functions and its modifications

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STEM FUNCTIONS AND MODIFICATIONS Made By: Pranav Ahlawat

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Page 1: Stem Functions And its modifications

STEM FUNCTIONS AND MODIFICATIONS

Made By:Pranav Ahlawat

Page 2: Stem Functions And its modifications

What Exactly is a Stem? Before we go any further in this

presentation, let’s define a stem. A stem:

is generally considered to be the central axis of the plant.

supports the leaves and flowers of a plant. has nodes from which new shoots and

sometimes new roots can arise. is usually found above-ground, but can be

modified and found below-ground as well.

Page 3: Stem Functions And its modifications

The Plant Body: StemsFUNCTION OF STEMS Stems support leaves and

branches. Stems transport water and

solutes between roots and leaves.

Stems in some plants are photosynthetic.

Stems may store materials necessary for life (e.g., water, starch, sugar).

In some plants, stems have become adapted for specialized functions.

Page 4: Stem Functions And its modifications

Stems support a display of leaves.

Stems orient the leaves toward the light with minimal overlap among the leaves.

Asclepias - milkweed

Page 5: Stem Functions And its modifications

Modified & Specialized Stems

Page 6: Stem Functions And its modifications

Food Storage Stems - Asparagus

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Cacti - stout fleshy stems that are modified for food and water storage and photosynthesis.

Photosynthetic Stems

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Tuber

Tubers - accumulation of food at the tips of underground stolons

The "eyes" of a potato are the nodes of a starch-ladened stem

Page 9: Stem Functions And its modifications

Corms

A corm is a swollen, vertical stem with a papery covering.

Gladiolus and Crocus are examples of plants that form corms.

Crocus corms

Page 10: Stem Functions And its modifications

Bulb

Bulbs - large buds with a small stem at the lower end surrounded by numerous fleshy leaves, adventitious roots at base

Examples include onion, tulip, and lily

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Rhizomes

Rhizomes - horizontal stems that grow below the ground with adventitious roots

Examples of plants that can produce rhizomes are irises, ferns, and grasses.

Page 12: Stem Functions And its modifications

Rhizomes

Other plants, like ginger, produce large, thick rhizomes called pachymorphs.

The pachymorph rhizome of Ginger

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Thorns

Honey locust (modified stem)

Black Locust (modified leaf stipules)

Page 14: Stem Functions And its modifications

Tendrils

Grape Tendrils

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Stolons

Stolons or runners - horizontal stem that grows above the ground with long internodes

Examples of plants that can produce stolons are strawberry and airplane plants

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Conclusion

A stem : supports leaves and branches. transports water and stores food. performs photosynthesis. performs specialized functions in different

conditions.

Stem Modifications:

• Tuber• Stolon• Corm• Tendril• Bulb• Rhizome

Page 17: Stem Functions And its modifications

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