PLANTS

Lesson 1: What are the main parts of a plant?

Why Plants need leaves?A plant’s leaves make up its leaf system. A system consists of parts that

work together. The main job of a leaf is to make food for a plant. Leaves do this by using sunlight for energy to take apart water from the ground and carbon dioxide from the air. Leaves use parts of water and carbon dioxide to make sugar. This food making is called photosynthesis, a large word which means making something new (synthesis) using light (photo).

Other ways Leaves help Plants…Water gets to the leaf through a set of pipes inside the tree which goes all the way down to the roots. Roots take water in from the soil so that it can be used by the tree. There are also chemicals in the water which help the plant stay healthy, a lot like vitamins help people stay healthy. In winter, the ground freezes. This makes it hard for water to get into the soil. Roots can't get as much water from the soil in winter as in the warm seasons of the year.

A plant´s leaves may also help to protect the plantfrom being eaten. Leaves might be poisonous, sharp,

tough to chew. hungry animals will leave the plantalone.

Photo: Stinging needle (Urtica dioica)

Lesson 2: Why do plant need roots and stems?

TYPES OF ROOTS

-The root system is often below the ground where you cannot see it. -The roots hold the plant in the ground.-Roots take in water and materials from the soil.-Roots also store food made by the plant.

Parts of roots

Primary root: originates at germination stage at theradicle of the seed.

Secondary root: arise fromThe primary root.

Root cap: indicates growth of new cells.

Root hair: tiny one celled hair-likeextension that increases the plant´sability to absorb water and mineralsfrom the soil.

StemsA plant’s stems hold up its leaves, flowers, and fruits. Most plants havetubes that move water and minerals from the roots of the plants to thestems and roots.

Example: notice how thick cactus stems can be. Cactus stems swell up as they storewater. The stem shrink as the plant uses water. Cactus stems also have a thick, waxycovering to help keep them from losing water. This type of stem helps the cactus survive in a desert. Also some stems have thorns, spines and stinging hairs to keephungry animals from eating them.

When you eat a potato, you eat a stem part that stored food underground. Undergroung stems can sprout new stems from buds such as the potato’s

«eyes». These parts grow upward and become new plants