Plants in the Surroundings and Environment Chapter Notes | Science Class 4 ICSE PDF Download

Introduction

Parts of a Plant

• Plants have various parts, each with a specific job.
• Roots anchor the plant and take in nutrients and water from the soil.
• Stem supports the plant, keeping it upright, and transports water, minerals, and food.
• Leaves, usually green and flat, make food through photosynthesis and help in gas exchange via stomata.
• Flowers help the plant reproduce and often turn into fruits.
• Fruits protect the seeds inside them.

Root System

• The root system includes all the roots of a plant, growing below the ground.
• Roots hold the plant firmly in place.
• There are two main types of roots: taproot and fibrous root.
  • Taproot is a single, thick root that grows deep into the soil with smaller roots branching out, seen in plants like beans, mustard, radish, and carrot (common in dicot plants).
  • Fibrous roots are many thin roots spreading out from the stem’s base, found in plants like onion, grass, maize, and rice (common in monocot plants).

Functions of Root

• Roots keep the plant stable in the soil.
• They prevent soil erosion by holding the soil together.
• Roots absorb water and minerals through tiny root hairs.
• Taproots reach deep into the soil for water, while fibrous roots spread out to absorb more water.
• Some roots, like those of carrots, radish, and sweet potatoes, store food.

Shoot System

Stem

• Stem is the part from which branches, leaves, flowers, and fruits grow.
• Stems can be strong (like tree trunks) or weak (like in herbaceous plants, climbers, or creepers).
• Some plants have highly branched stems.

Functions of Stem

• Stems give the plant strength to stand upright.
• They carry water and minerals from roots to leaves for food production.
• Stems transport food made in leaves to other parts of the plant.
• Some stems, like those of potato, ginger, and sugarcane, store food and are edible.

Leaves

• Leaves are called the food factories of green plants as they prepare food for the plant by the process of photosynthesis. 
•  They differ greatly in size, shape, and colour.

Structure of a Leaf

• The leaf blade or lamina is the flat, broad part of the leaf.
• The petiole connects the leaf to the stem.
• The main vein (midrib) runs from the petiole to the leaf tip, splitting the leaf into two equal parts.
• Veins form a network to carry water and minerals across the leaf.
• Stomata are tiny openings on the leaf’s underside that help in gas exchange.

Functions of Leaves

• Leaves make food through photosynthesis, using carbon dioxide, water, sunlight, and chlorophyll.
• Chlorophyll, the green pigment in leaves, absorbs sunlight for food production.
• Leaves are called the food factories of plants.
• The food made is glucose (sugar), which the stem transports to other plant parts.
• Extra glucose is stored as starch in leaves.
• Stomata allow gas exchange and transpiration (loss of water as vapor).
• Transpiration cools the plant and aids nutrient transport from roots to shoots.
• Some leaves, like those of lettuce and spinach, store extra food.

Things We Get from Plants

• Plants provide many useful items for daily life.
• Food items include cereals, pulses, nuts, fruits, vegetables, oils, and spices.
• Beverages like coffee and tea come from plants.
• Wood from trees is used for furniture, boats, doors, and windows.
• Fibers from plants like jute, cotton, and flax are used to make clothes and bags.
• Linen clothes are made from flax plant fibers.
• Coir from coconut husks is used for ropes, doormats, and mattresses.
• Rubber and gum come from plants.
• Bamboo pulp is used to make paper.
• Medicinal plants like tulsi, neem, mint, and eucalyptus are used to make medicines.

Terms to Know

• Root System: The part of the plant below the ground, made up of roots.
• Shoot System: The part above the ground, including stem, leaves, flowers, and fruits.
• Petiole: The part that connects the leaf to the stem.
• Stomata: Tiny openings on the leaf’s underside for gas exchange.
• Photosynthesis: The process by which green leaves make food.
• Transpiration: The process of water loss from plants as vapor.
• Glucose: A type of sugar made by plants during photosynthesis.
• Chlorophyll: The green substance in leaves that absorbs sunlight.