Science Form 2 Chapter 8.2

CHAPTER 8: SUPPORT AND

MOVEMENT

8.2 SUPPORT SYSTEMS IN PLANTS

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.

Adequate Water in Plants

Inadequate Water in Plants

VARIOUS SUPPORT SYSTEMS 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.

VARIOUS SUPPORT SYSTEMS IN PLANTS

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

VARIOUS SUPPORT SYSTEMS IN 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

VARIOUS SUPPORT SYSTEMS IN 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.

VARIOUS SUPPORT SYSTEMS IN PLANTS

Thorns

PRICKLES (NON-WOODY PLANTS)

A prickle = an outgrowth of the epidermis and can be easily removed from the stem.

Example : rose

VARIOUS SUPPORT SYSTEMS IN PLANTS

Prickles

AIR SACSThe 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.

VARIOUS SUPPORT SYSTEMS IN PLANTS

Air Sacs

STILT ROOTSMangrove trees which grow in muddy places have stilt roots that provide additional support.

Stilt roots develop from the main stem of the mangrove trees.

VARIOUS SUPPORT SYSTEMS IN PLANTS

Stilt Root