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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.