Parts of Plants: Structure, Functions, Types, Examples (Grade 3)

This is a comprehensive lesson plan for teaching insects to grade 3 students. The lesson is designed to make the concepts easy and engage students with activities like quizzes, practice questions, and real-life examples.

Teachers can use this guide as a reference for delivering the concepts to students and engaging them in the classroom with the various questions and examples given in this page.

In this article, you will learn:

• types of plants
• different parts of a plant
• structure and functions of roots, stem, and leaves
• flowers and their functions
• structure and functions of fruits and seeds
  
  

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Plants: Introduction

Plants are living things that grow all around us. They are important because they provide food, air, and shelter to many living creatures, including humans. Let's learn about plants & their different parts.

Types of Plants

Plants are classified into different categories based on similar features.

Flowering and non-flowering plants are two major categories of plants.

• Plants that produce flowers are flowering plants. Examples: tulips, daffodils

• There are some types of plants that do not flower at all. Examples: ferns, mosses

Plants can also be classified, according to the habitats where they are growing.

• Terrestrial plants grow on land. Examples: pine trees, cactus

• Aquatic plants grow in water. Examples: lotus, hydrilla

 

Classification of Plants Based on Size and Nature of Their Stem

Big Plants (Trees): Capable of forming tall & stout tree-like structures with thick woody stems Examples: Neem, Banyan.

Small Plants (Shrubs & Herbs): Shrubs have slender, woody stems (as you might find with jasmine), while herbs have soft stems (such as coriander).

Weak-Stemmed Plants: Climbers (like peas) & creepers (like cucumber).

• Climbers: Plants that need support to grow upward (like money plants & grapevines).

• Creepers: Plants that grow along the ground (like watermelon & pumpkin).

 

The Different Parts of Plants

Plants are essential to the life of all living beings on earth. They maintain ecosystems in multiple ways. This article explores the ways in which various regions of a plant function.

1. Root System: The primary root and other roots extend down into the soil, anchoring the plant, absorbing water, & collecting nutrients. They also aid in providing stability to the plant.

2. Shoot System: The top half of the plant consists of these parts -

• Stems: These give support to the plant, facilitating the flow of water, nutrients, and food between the roots & leaves. They also store food.

• Leaves: They are the main photosynthetic organs of the plant. Leaves take in sunlight and convert it into energy. They also help with gas exchange: carbon dioxide & oxygen.

• Fruits: It has seeds, and it helps in the dispersal of the seeds. The flesh of the fruit is often sweet to lure animals, which in turn spread the seeds.

• Flowers: These are the reproductive structures of the plant. The plants have both male and female parts, which allows cross-pollination & ultimately produces seeds for the next generation of plants.

 There are different structures in different parts of the plant to allow it to survive & reproduce.

 

The Structure and Functions of the Roots of a Plant

Root Structure

The roots are long & thin. Or straight, go deep, or spread out (taproots & fibrous).

Roots typically extend deep into the ground & can be classified into two root architectures:

• Taproot System: A single, thick root grows directly down into the soil to obtain deep-water and mineral ions. From this large taproot come smaller roots. Examples: radish, carrot, mustard, & bean.

• Fibrous Root System: A mass of small, thin roots that spread out horizontally from the base of the plant but usually not far into the soil. Examples: grass, wheat, & onion.

Root Functions

At the core of this is the plant root system which performs several critical functions:

• Anchoring: The main activities of the process are anchoring the plant into the soil.

• Absorption: This process is crucial for plants to grow and for food production; therefore, roots absorb both water & nutrients from the soil.

• Storage: Some plants store food in their roots and are considered edible. Examples of root vegetables include beetroot, carrot, radish & turnip.

 

The Structure and Functions of the Stem of a Plant

Stem Structure:

The stem is an important part of shoot system.

1. It has a growth on the surface which upholds other parts of a plant like leaves, blooms, and organic products.

2. The different types & structural functions of stems.

3. Trees need thick hard stems known as trunks, for example, mango & coconut trees.

4. Others, such as the ones in mint, coriander & onion plants, have slender, supple, green stems.

5. Plants such as the money plant, pumpkin, and watermelon have weak and thin stems that need support to grow upright.

Stem Functions:

1. It helps to keep the plant upright.

2. Assists in moving water up to the leaves.

3. Facilitates the movement of food produced by the green parts of the plant to the remaining parts of the plant.

 

The Structure and Functions of the Leaves of a Plant

They have different sizes and shapes and are usually green, as they contain a pigment known as chlorophyll. Chlorophyll allows the leaves to synthesize food for the plant using photosynthesis.

Leaves of different plants are of different size and shape. For example,

• Banana leaves are large and long and ovate.

• Lotus leaves are broad and round.

• Peepal leaves are heart-shaped. Mango leaves are elliptic in shape.

Leaves Structure: 

A leaf is a thin, broad, & flat structure attached to the stem by a stalk called the petiole. It is typically green in color.

The structure of a leaf includes the following parts:

1. Leaf blade or lamina: The broad, flat part of the leaf. Its lower surface is rough and lighter in color, while the upper surface is smooth & darker.

2. Stomata: Small pores on the underside of the leaf blade through which it breathes & through which it can exchange gases in photosynthesis.

3. Petiole: The stalk by which a leaf attaches to the stem.

4. Midrib: A large central vein that runs all along the length of the leaf from the base via the petiole up to the tip.

5. Veins: Smaller veins that branch off from the midrib to form several patterns across the surface of the leaf.

Leaf Functions:

Leaves have several important functions:

1. They make food for the plant through photosynthesis.

2. Chlorophyll is the green pigment in leaves that absorbs sunlight, which is essential for photosynthesis.

3. Leaves enable gas exchange needed for photosynthesis through their stomata.

4. In some plants, the leaves can store food and be edible. Some examples are cabbage, spinach, & lettuce.

 

Flowers and Their Functions

Flowers are the most beautiful part of the plants & also fragrant.

Flower Structure:

• Flowers have petals (often colorful), a stalk, & parts inside like stamens (male part) & pistils (female part).

• Flowers are a part of the shoot system.

• They can be seen in different sizes and shapes & colors.

• They play a crucial role in plant reproduction as fruits & seeds develop from flowers.

• Plants can be classified into two types, viz., flowering & non-flowering.
  In some plant species, the flowers are consumable. Other edible flowers are cauliflower & broccoli.

 Flower Functions:

• Attract insects like bees for pollination.

• Help in the production of seeds by pollination.

 

The Structure and Functions of Fruits and Seeds

A fruit is the seed-bearing part of flowering plants. Most flowers develop into fruits that enclose seeds. 

Fruits can contain one, a few, or many seeds: 

• Fruits like mango, avocado, gooseberry, & lychee have a single seed.

• Fruits like apples and lemons bear a few seeds. 

• Tomatoes, oranges, kiwis, watermelons, & papayas are some fruits that bear more than a few seeds.

Seed Structure: 

In general, the majority of the seeds have three distinct parts: 

• Seed coat: Protective outer layer surrounding & protecting the seed.

• Food store: A nutrient reserve that supplies essential starches & proteins to the baby plant for growth.  

• Embryo: This is the portion of the seed to be formed into roots, stem, & leaves of the plant. It is often referred to as the "baby plant."

Seed Functions:

The process of growing a seed into a young plant or seedling is called germination. A seed requires an adequate amount of water, air, warmth & nutrients for germination to take place.

The functions of a seed are explained below.

• Seeds germinate into new plants.

• Seeds contain food reservoirs. Therefore they are sources of stored food for the embryos.

• The seed coat protects the embryo.

• Seeds of some plants that are edible both for humans & animals.

 Edible seeds are coffee beans, chia seeds, flax seeds etc. And seeds from which oil was extracted include safflower, sunflower, soyabean, sesame, olive, and rapeseed.

Things you have learned!

• Discover different types of plants and how they are grouped.
• Find out the main parts of a plant and their uses.
• Learn how roots, stems, and leaves help a plant grow.
• Understand why flowers are important for making new plants.
• See how fruits and seeds help plants reproduce.