Plants and Their Adaptations

Lesson A4.1What are the functions of roots,

stems and leaves?

Common parts

• Vascular plants have three parts in common- roots, stems and leaves.

• They live and grow almost everywhere, from dry deserts to wet jungles to cold Arctic plains.

• Each part of a vascular plant has a different function.

Roots

• Roots spread out about or farther than the branches do.• Most plant roots act as anchors. They keep the plant

from blowing away or falling over.• Nutrients enter the roots through tiny parts called root

hairs.• Some tree roots begin above ground- these are called

prop roots. These help trees grow in loose, wet soil.• Fibrous roots look like tiny tree branches. They help

prevent soil erosion by wind and water because they anchor the soil as well as the plant.

More roots

• Storage roots are roots that store extra food and water. We eat many storage roots because they store food in the form of sugar so the veggie is sweet.

Stems

• Stems do several things for plants.• They hold the plant up, they support the leaves to get sunlight,

and they carry food and water to other parts of the plant.• Most plants grow upward.• Some plants grow sideways instead of up.• Many desert plants have stems that store food and water.• Xylem- tubes that transport the nutrients and water.• Phloem- tubes that carry the food from the leaves to other

parts of the plant.• The xylem is towards the center of the stem but the phloem is

on the outside of the stem.

Leaves

• Leaves are the “food factories” of plants.• The food making process is called photosynthesis.• It also produces oxygen which gets released into the air.• Chlorophyll- a pigment helps plants use light energy to

make sugars.• It gives leaves their green color so without it, they

change into their “normal” color.• Chloroplasts are where the food making actually occurs. • Stomata- tiny holes where carbon dioxide enters a leaf,

and oxygen and water leave the leaf.