Investigate Plant & Flower Anatomy

Plant anatomy relates to the structures and systems of plants that allow them to survive, grow, and reproduce. Each structure has a specific function to help the plant survive in its environment.

Investigate
Plant & Flower Anatomy

Plant anatomy relates to the structures and systems of plants that allow them to survive, grow, and reproduce. Each structure has a specific function to help the plant survive in its environment.

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Plant Structures and Functions

Pollination Process and Seed Formation

Plant Structures and Functions

In order to survive, plants need the basic resources necessary for life.

Food

Water

Sunlight

Air

Plants have structures that help with obtaining the resources necessary for life.

Roots:

Plant roots grow underground and take up water and minerals from the soil.
Roots provide storage for sugars made by the leaves.
They also help anchor the plant to prevent it from blowing over or washing away.
Plants may either have a taproot system (one main root that grows downward with several smaller roots growing from the main root) or a fibrous root system (with many threadlike roots, all of which are about the same length).

Roots
flickr – Science and Plants for Schools

Root Systems
Wikimedia – Cassandra gonzales

Leaves:

Plants can make their own food using energy from sunlight through a process is called photosynthesis.
Plant leaves convert water and carbon dioxide (a gas found in the air) into sugars called carbohydrates.
The leaves also release oxygen (a gas found in the air) back into the environment as a result of the process.

At night, when sunlight is not available for plants to use, they undergo a process called cellular respiration.
This is the process in which oxygen is used to break down carbohydrates.
Carbon dioxide and water are released as a result of the process.

Photosynthesis Diagram
Dreamstime

Leaves
flickr – Live Once Live Wild

Fern Frond
Dreamstime

Stems:

The stems provide support for the leaves and flowers.
They also transport water and minerals throughout the plant.
Stems can be herbaceous (soft and green) or woody, and they can be branched or unbranched

Herbaceous Stems
flickr – USFWS Midwest Region

Woody Stems
flickr – Fredericy County Forestry Board

Internal Structures:

Stems and roots contain tubes for transporting water, minerals, and sugars throughout the plant.
- The xylem transports water from the roots to the stems and leaves.
- As water evaporates through the leaves, the roots take up more water from the soil. This process is called transpiration.
- Phloem transports sugars that were made during photosynthesis from the leaves to the roots and stems.

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Parts of a Flower

A flower is a specialized structure for reproduction, allowing the male and female parts to join to create a new “baby” plant.

Flowers are generally brightly colored and come in various shapes and sizes.

Rue-anemone Flower
Wikimedia – Dcrjsr

Purple Cone Flower
flickr – It’s No Game

Lizard’s Tail
Wikimedia – bobistraveling

Flowers are made of many parts, each with a specific funtion that helps the plant with the reproduction process.

Sepals and Petals:

Sepals: when a flower is budding, the sepals surround and protect the developing flower. They also provide support for the flower petals once the flower has opened and is in bloom. They are often green in color.

Petals: usually brightly colored and surround the reproductive parts of the flower. The colors, shapes, and smells attract pollinators to the plant.

Flower Petals and Sepals
Wikimedia – Alpsdake

Nectar Guides (on bottom photo)
Wikimedia – Dave Kennard
Click here to view a presentation about pollinator vision and how they perceive color

Different types of pollinators tend to prefer different types of flowers based on the characteristics or traits of the flowers. The relationship between pollinator characteristics and which flower types they prefer and are successful in pollinating is called a pollination syndrome. Flower traits include flower shape, flower color, flower smell, amount of pollen, amount of nectar, and the presence or absence of nectar guides. Nectar guides are markings on flowers that guide pollinators to where the nectar is located. Many pollinators can see light wavelengths that humans cannot, making these markings invisible to us.

Click here to view a “Pollinator Syndrome Comparison Chart” with a description of the flower characteristics preferred for each type of pollinator

Stamen:

The male part of the flower is called the stamen.
The stamen is composed of two structures.
- Anther: oval shaped structure that produces pollen.
- Filament: long, thin tube that supports the anther.
Pollen is the yellow or orange powder found in flowers. It contains a set of genetic material from the male part of the plant.

Adobe Stock

Pistil:

The female part of the plant is called the pistil. The pistil can be a single carpel or made of several fused carpels.
The pistil (or carpel(s)) is composed of three structures.
- Stigma: sticky structure located at the tip of the pistil. The stigma collects pollen.
- Style: tube connecting the stigma to the ovary. Pollen travels down the tube after landing on the stigma.
- Ovary: enlarged structure at the bottom of the pistil. The ovary makes ovules which hold the female genetic material and will later develop into seeds.

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Pollination Process and Seed Formation

For a plant to reproduce, pollen from a flower on one plant needs to be transferred to a flower on another plant. This process is called pollination.

The animals that help move pollen from one flower to another are called pollinators.

In Alabama, pollinators include bees, butterflies, hummigbirds, beetles, ants, moths, and wasps.

Pollination Process:

1. Pollinator visits flower

In addition to pollen, flowers contain a sugary liquid called nectar.
Nectar and pollen provide a source of food and energy for pollinators.
Many pollinators have a specialized tongue-like mouthpart called a proboscis that is used to collect nectar.

2. Pollen sticks to pollinator

As the pollinator searches the flower for nectar, pollen from the anthers sticks to the pollinator’s body.

Bee Collecting Pollen
Dreamstime

3. Pollinator visits other flowers

Pollinators visit several flowers from several plants as they search for food.

4. Pollen is transferred to the stigma

As pollinators visit flowers, pollen that was attached to their body from other flowers is deposited onto the sticky stigma.

Bee Depositing Pollen
Dreamstime

Freepik.com

Seed Formation Process:

After pollen has been deposited on the sticky stigma, the pollen travels down the tube-shaped style and reaches the ovary.
The ovary contains ovules.
When the pollen joins the ovules, fertilization occurs, and seeds are formed.
The seed contains a protective coat surrounding an embryo, the “baby plant” roots, along with a nutrient source for the embryo.
The ovary becomes the fruit that protects the seeds.

Dreamstime

Plant Life Cycle

After fertilization occurs and the seed is formed, the plant life cycle can continue.

1. Seeds:
Seeds contain the new plant (embryo) and nutrients inside of a protective coat. They must be dispersed (moved to a new location).

2. Sprout (or cotyledon):
Once a seed lands in a suitable environment, it will germinate (begin to grow). Small roots will begin growing into the soil, and a small leaf is developed.

3. Seedling:
The sprout will continue to grow into a seedling, developing a stem and leaves above the ground.

Dreamstime

4. Adult:
As the seedling continues to grow, it will eventually develop into a mature adult plant. Mature adult plants are able to produce flowers that can be pollinated. The pollination process leads to the formation of new seeds, and the cycle continues.

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