Transcript Plant Structure and Function

PLANTS
Plants: Grouped by
characteristics
• Nonvascular
– Simple; most grow in moist places
– No vascular tissues.
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No way to move around water and nutrients
Need to live close to water
Mosses, liverworts, ferns
Evolved first
• Vascular
– Have Vascular tissues: roots, stems and leaves
– Allows them to grow large and in many different
environments
– Includes trees, flowering plants, crops, etc….
Non vascular = Bryophytes
• Only nonvascular plants (mosses, liverworts)
• no ability to internally transport water and
materials
• requires moist environment
• live in colonies, has rhizoids to anchor it
• important in soil formation
Vascular Plants - Tissues
Plants have 3 tissue systems:
• Ground tissue
– Photosynthesis, food storage, regeneration,
support, protection
• Vascular tissue (xylem and phloem)
– Movement of materials
• Dermal tissue (exterior)
– Protection and prevention of water loss
Plants: Stems
• Function of stems
– Support, transport of water & food
• Green
• Woody
– Transport of materials
• xylem - conducts water and minerals
• phloem - conducts food
Growth
• Plant growth occurs at specialized areas
called meristems (meristematic tissue)
• Primary growth = growth in length
• Secondary growth = growth in girth
Leaf function
• Photosynthesis - more later
• Transpiration - 99% of water absorbed by
plant is lost by transpiration
• Stomata are tiny holes on the bottom of the
leaf that let gases and water in and out
– Opening controlled by guard cells
Photosynthesis
 Uses carbon dioxide, water, and
sunlight - reactants
Releases oxygen and makes sugar,
oxygen is released - product
chlorophyll – the
green substance
found in plants that
traps energy from
the sun and gives
plants their green
color
chloroplasts - where
photoysynthesis
happens
Plant Evolution
• First = Bryophytes - no roots, leaves or
stems, no vascular system, simple
reproduction relying on water.
Second = Ferns - first vascular system
– Reproduce using spores
Gymnosperms
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Vascular, seed bearing, flowerless plants
means “naked seed”
largest division is conifers
leaves are called needles
Pines, cedars, spruces, firs
Angiosperms
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Flowering, vascular plants
Most successful plants: deciduous trees
Magnolias, roses, apple trees
Plant Parts
– Pistil – part of a flower that makes the eggs that grow into seeds
– Stamen – part of a flower that makes pollen
– Pollen – tiny grains that make seeds when combined with a flower’s
egg
monocot seed – a seed
that has one seed leaf
and stored food outside
the seed leaf
dicot seed – a seed
that has two seed
leaves that contain
stored food
Plant Adaptations
• Specialized tissues – vascular tissues
• Cuticles
– Waxy coating on surfaces
– resists drying out
– stomata exist to allow necessary gas exchange
• Alternation of generations
– Plants live part of their life in a haploid stage and part
in a diploid stage
– haploid portion = gametophyte
– diploid portion = sporophyte
• Co-evolution with pollinators