Science Form 2 Chapter 8.2

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Text of Science Form 2 Chapter 8.2

Plants are classified as Woody Non-woody Woody plants with a single stem are called trees. Woody plants that develop branches close to the ground are called shrubs.

Mango Tree

Hibiscus shrubs

Non-woody plants are also known as herbs. Non-woody plants depend on the water stored in the cells of the stem for support. When there is not enough water in these cells, the plants wilt.

Inadequate Water in Plants Adequate Water in Plants

BUTTRESS ROOTS (WOODY PLANTS) The taproot system of large trees does not provide good support. Many of these large trees have buttress roots at the base of the stem to provide extra support. These roots form a very strong base, enabling the trees to grow very tall. Examples: rain tree, flame of the forest, rubber tree, durian tree

Buttress Root

PROP ROOTS (WOODY PLANTS) The prop roots of the banyan develop from the branches to grow downwards into the ground to give the tree extra support. Prop roots of maize grow from the nodes of the stem close to the soil surface.

Prop Root

CLASPING ROOTS (NON-WOODY PLANTS)

Clasping roots enable the plant to climb by growing around and clasping its support. Examples : orchids, money plants, pepper plants

Clasping Root

TENDRILS (NON-WOODY PLANTS) A tendril = a coiled structure which develops from the stem or leaf. Tendrils wind themselves around the support and help the plant to climb. Examples : cucumber, garden pea, pumpkin, long bean, bitter gourd plants

Tendrils

THORNS (NON-WOODY PLANTS) A thorn = a modified branch and it cannot be easily removed from the stem. The rose and the bougainvillea plants climb by means of thorns.

Thorns

PRICKLES (NON-WOODY PLANTS) A prickle = an outgrowth of the epidermis and can be easily removed from the stem. Example : rose

Prickles

AIR SACS The brown algae is common on rocky shores. It is alternately exposed and covered by the tides every day. This alga has air sacs for support because the air sacs provide buoyancy.

Air Sacs

STILT ROOTS Mangrove trees which grow in muddy places have stilt roots that provide additional support. Stilt roots develop from the main stem of the mangrove trees.

Stilt Root