Olympiad Notes: Getting to Know Plants | Science Olympiad Class 6 PDF Download

Introduction

• Observing the surroundings in parks and gardens reveals a variety of plants with distinct features.
• Different plants exhibit various leaf shapes, flower shapes, flower colors, and stem sizes.
• Some plants tower above, displaying tall heights, while others remain short and compact.

Herbs

• Herbs are characterized by green and tender stems.
• They are utilized in various ways such as in food, flavoring, for their pleasant aroma, and for medicinal purposes.
• Examples of herbs include mint (Pudhina), rosemary, coriander (Dhaniya), bay leaf (Tejpatta), and basil (Tulsi).

Shrubs

• Shrubs are plants characterized by stems branching out near the base with a hard but not excessively thick structure.
• They typically have shorter heights and multiple stems.
• Often cultivated in gardens, shrubs serve decorative purposes due to their appearance and growth patterns.

Trees

• Trees are characterized by their tall height and possess hard, thick, and brown stems.
• These stems typically feature upper branches that extend far above the ground.
• Examples of trees include the apple tree, mango tree, neem tree, coconut tree, oak tree, and many others.

Creepers

• Creepers are plants characterized by weak stems that require support to stay upright as they are unable to stand on their own. Instead, they tend to spread along the ground.
• Examples of creepers include the pumpkin, watermelon, sweet potato, muskmelon, and various other plants.

Climbers

• Climbers are plants that rely on neighboring structures such as walls, trees, or fences for support as they grow upwards.
• These plants utilize their climbing ability to ascend and thrive.
• Examples of climbers include the money plant, pea plant, grapevine, bean plant, and various other species.

Stem

• The stem of a plant serves as a structural support for leaves, flowers, and fruits.
• It plays a crucial role in transporting fluids from the roots to different parts of the plant.
• Fluid movement, including water and minerals, occurs through a narrow tube within the stem known as the xylem.

Leaf

• The shoot is formed by the combination of leaves and stems.
• The attachment point of a leaf to the stem is known as the petiole, while the broad green section of the leaf is referred to as the lamina.
• Veins on a leaf are responsible for providing support and transporting water and minerals throughout the leaf.
• The central, thicker vein running down the middle of the leaf is called the midrib.

Leaf Venation

• Leaf venation refers to the pattern formed by veins within a leaf.
• Reticulate venation is characterized by a net-like pattern on both sides of the midrib. Examples of plants with reticulate venation include coriander, rose, and oak.
• Parallel venation is identified by veins running parallel to each other within the leaf. Plants like grass, wheat, and maize exhibit parallel venation patterns.

Photosynthesis and Transpiration

• Stomata are tiny pores located on the upper surface of leaves.
• They facilitate the exchange of gases, allowing the intake of carbon dioxide and the release of oxygen during photosynthesis in the presence of water and sunlight.
• Photosynthesis is the process by which plants produce their food.
• Transpiration, a process vital to plants, creates a suction force within the plant, aiding the movement of water from roots to shoots and other parts.
• Water vapor is released into the atmosphere through the stomata on leaves, a process known as transpiration.

Root

• The root is the plant organ situated beneath the soil surface.
• Roots play a crucial role in anchoring the plant securely into the soil, providing stability.
• They absorb essential minerals and nutrients from the soil, vital for the plant's growth and sustenance.
• Plants possess three primary types of root systems: Tap root, Fibrous root, and Adventitious root.

Types of root system

• Tap root refers to the primary, larger, and rapidly growing root, accompanied by smaller branched roots known as lateral roots.
• Examples of plants with tap roots include beetroot, carrot, sugar beet, radish, among others.
• Fibrous root systems lack a main root; instead, all roots are of similar size.
• Plants such as coconut palm, onion, grass, and spring onion are examples of those with fibrous root systems.
• Adventitious roots are roots that develop on any part of the plant other than the typical root area.
• Notably, plants exhibiting leaves with reticulate venation typically have tap roots, while those with fibrous root systems tend to showcase leaves with parallel venation.

Flower

• Flowers primarily serve as the reproductive part of a plant and are identifiable by their various colors.
• Different components of a flower include petals, sepals, pistil, and stamen.
• Petals refer to the colorful segments that cover the reproductive section of the flower.
• Sepals are the outermost green parts that enclose the flower bud.
• Stamen functions as the pollen-producing part of the flower, consisting of the anther (containing pollen grains) and the filament (a supportive tube-like structure).
• The structure of the stamen includes these two integral parts: anther and filament.
• Pistil, the innermost part of the flower, is responsible for producing ovules.
• The pistil comprises three essential parts: stigma (the upper part receiving pollen for fertilization), style (a long, hollow tube connecting the stigma to the ovary), and ovary (where ovules are produced).
• Once matured, the ovary develops into a fruit, while mature ovules become seeds.