Plant Parts and their Functions

Leaves-Internal

Leaves-Internal• Upper and lower epidermis-skin of the

leaf that prevents the loss of too much moisture

• Cuticle: waxy protective coating on outer surface

• Stomas-small openings under the leaf for breathing or transpiration

• Guard Cells-open and close stomas

Leaves-Internal

• Air Space: CO2 & O2

• Vein: Movement of Fluid

• Xylem: transport water up

• Phloem: transport glucose

Leaves-Internal

• Chloroplasts-small green particles that contain chlorophyll– gives leaves their green color– necessary for photosynthesis

Leaves-Internal

Functions of Leaves

• Photosynthesis-manufactures food in green plants which is the beginning of the food chain for all living things

• Photosynthesis is the process by which carbon dioxide and water in the presence of light are converted to sugar and oxygen

Functions of Leaves

• Transpiration – loss of water through the leaves or stems of plants

• Transpiration exchange gases as oxygen and carbon dioxide

Stems• Movement of Materials

• Support of the leaves and reproductive structures

• Food storages

• Reproduction with stem cuttings or grafting

Stems-Internal (dicot)

Stems-Internal• Pith-dead center of stem for

support

• Heartwood-old inactive xylem

• Sapwood-new active xylem• Cambium-thin, green, actively

growing tissue located between bark and wood and produces all new stem cells

• Phloem-active

• Bark-old inactive phloem

Stems-Internal (Translocation)

• Xylem-tissue that transports water and nutrients up from the roots to stems and leaves

• Phloem-tissue that transports food down from leaves to roots

PhloemPhloem

Xylem

Stems-Internal• Monocot : examples: corn, grasses

• Dicot: example: trees

Functions of Stems

• Translocation – move water and minerals from roots up to leaves & move food from leaves down to the roots

• Xylem and phloem cells help with this process.

Functions of Stems & Leaves

• Transpiration – plant lose water from leaves and stems through evaporation

• Occurs in stomas and lenticels

Root Functions

• Anchor the plant and hold it upright

• Absorb water and minerals from the soil and conduct them to the stem

• Store large quantities of plant food• Propagate or reproduce some

plants

Roots-Internal

• Much like stems in that they have a phloem, cambium, and xylem layer

• Phloem-the outer layer that carries food down the root

• Xylem-the inner layer that carries water and minerals up to the stem

Layers of Roots

• Fibrous-many branched shallow roots– are easier to transplant

• Tap-long root with few branched ones– more difficult to transplant

Functions of Roots

• Absorption-take water and nutrients from the soil and conduct them to the stem

• Anchor the plant and hold it upright• Store food for plant use• Asexual reproduction in some

plants

Dioecious• Male and female, imperfect flowers

on same plant• Examples: Squash & Pumpkin

Functions of Flowers

• Produce seeds used for sexual reproduction

• Attract insects for pollination (Pollination is the transfer of pollen from anther to stigma.)

• Produce fruit to protect, nourish and carry seeds

Functions of Whole Plant

• Respiration – the process through which plant leaves, stems and roots consume oxygen and give of carbon dioxide.

• Plants produce much more oxygen through photosynthesis than they use through respiration.