UNIT 6. PLANTS (3º E.P.)

THE CHARACTERISTICS OF A PLANT

THE PARTS OF A PLANT

Plants have three parts: the roots, a stem and leaves.

*  The roots absorb water and minerals from the soil.

*  The stem supports the leaves. Water and minerals pass through the stem to the leaves. There are two types of stems:

- Hard stems: are called woody.

- Soft stems: are called herbaceous.

*  The leaves grow from the stem and branches and are usually green.

HOW A PLANT FEEDS

-  The roots absorb water and minerals from the soil.

-  Water and minerals go up through the stem to the leaves.

-  The leaves absorb carbon dioxide from the air.

In the leaves, the plant uses energy from The Sun and the substances it absorbs to make its own food. This process is called photosynthes and needs a substance called chlorophyll which is in the leaves and soft stems.

HOW A PLANT REPRODUCES

To reproduce, most plants grow flowers in spring. Flowers have different parts:

-  Petals are coloured. A group of petals is the corolla.

-  Sepals are small green leaves. A group of sepals is the calyx.

-  Stamens make pollen.

-  Pistil is the place where the fruit grows.

The seeds grow inside the fruit. When the fruit falls to the ground a new plant grows from the seed.

FRUITS AND SEEDS

Each plant produces a different fruit.

We classify fruits in two groups:

v  Fleshy fruit is juicy because it has a lot of water like pears, apples, melons, etc.

v  Nuts do not have a lot of water like acorns, nuts.

Seeds are inside fruit.

Some fruits have only one seed, such as peach, avocado, plum. Others have a lot of seeds.

Some seeds are soft, like tomato. Others, like lemmon, are hard.

THE LIFE OF A PLANT

HOW A PLANT GROWS

Plants need sunlight, water and the right kind of soil to grow.

During the life of a plant:

-  The stem grows taller and thicker. Branches grow from the stem.

-  The roots grow down into the ground. They divide into smaller roots, like branches.

-  The leaves get bigger and new leaves grow.

-  The plant grows fruit and reproduces.

Some plants are small and live for a short time. Other plants are and grow very big and live for a very long time.

TYPES OF PLANTS

There are many different types of plants. One way to classify is by size:

·  Grasses, or herbs, are the smallest plants (green, thin and flexible stem) like chamomile, reeds.

·      Bushes, or shrubs, are bigger than grasses (thin and woody stem with branches), like cactus, broom.

·      Trees are the biggest plants, they have trunk and branches, like pines, oaks.

Vegetation is the name of all different plants that grow in a particular place.