PLANTS

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PLANTS
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PLANTS

• Plants
• Nearly all alike
• Differences due to variations in structures
• Leaves
• Roots
• Stems
• Flowers
• seeds

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PLANTS

• PRIMITIVE PLANTS
• MOSSES
• Small, no true plant structures
• Rhizoids instead of roots
• Lie low to ground
• Require water for fertilization
• Reproduce both asexually sexually
• No vascular tissue food and water transporting
  tissue without it size is limited to what can be
  diffused

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PLANTS

• PRIMITIVE PLANTS
• FERNS
• no true plant structures
• Rhizoids instead of roots
• Fronds leaf-like structure
• Require water for fertilization
• Reproduce both asexually sexually
• HAVE VASCULAR TISSUE
• Makes them different from mosses so they can be
  bigger

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PLANTS

• OTHER VASCULAR PLANTS
• HAVE VASCULAR TISSUE
• XYLEM CONDUCTS WATER
• PHLOEM CONDUCTS FOOD
• Gymnosperms
• Plants that have naked seeds
• No protective covering like fruit or nut over the
  seed
• Include
• Conifers pine trees
• Have needles for leaves

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PLANTS

• ANGIOSPERMS
• Flowering plants
• Most numerous type of plants
• Divided into two classes
• Monocots
• Corn
• Lilies
• Bananas
• iris
• Dicots
• Most angiosperms

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PLANTS

• ROOTS
• TWO TYPES OF ROOT SYSTEMS
• Taproots grow deeply in soil
• Primary root grows straight into ground
• Examples carrot, dandelion, most plants
• Fibrous roots primary root doesnt live long
• Many slender branching roots develop
• Covers large area of land prevent soil erosion
• Shallow
• Examples corn, grasses

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PLANTS
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FIBROUS OR TAP ROOT?
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PLANTS

• FUNCTION OF ROOTS
• Anchor the plant
• Absorb water
• Store food
• STRUCTURE OF ROOTS
• Root tip is divided into four areas

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PLANTS
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PLANTS

• ROOT TIP
• Maturation region region where cells
  differentiate into different tissues (xylem,
  phloem, etc)
• Root hairs form
• Extensions of epidermal cells
• Increase surface area
• Function in extra absorption

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ROOT HAIRS
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PLANTS

• ELONGATION REGION
• Cells become 2-3 times longer
• REGION OF APICAL MERISTEM
• Mitosis take place very rapidly
• Region of great cell growth
• ROOT CAP
• Acts as a shield to protect other layers

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PLANTS
MATURATION REGION
ROOT HAIR
EPIDERMIS
ELONGATION REGION
REGION OF MERISTEM
ROOT CAP
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PLANTS

• STEMS
• FUNCTION
• Support leaves
• Photosynthesis in green stems
• Transport of food and water
• Specialized stems function in food storage
• Determines plants overall size and shape

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PLANTS

• HERBACEOUS STEMS
• Green stems
• Flexible
• Small in diameter
• Non-woody only have primary tissues
• Not as strong as woody stems

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PLANTS

• PRIMARY TISSUES
• Epidermis outer covering
• Cortex carries on photosynthesis
• Near epidermis
• Pith surrounds vascular bundle
• Vascular bundle (tissue)
• Encloses xylem phloem cambium

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PLANTS

• VASCULAR BUNDLE
• Monocots (class of angiosperm)
• Bundles are scattered
• Look like monkey faces
• Eyes, nose, mouth are xylem
• Forehead is phloem
• Dicots (class of angiosperm)
• Bundles are in circular arrangement around edge
  of stem
• Phloem is on outside edge of bundle

PHLOEM
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PLANTS

• GROWTH OF STEMS
• Begins with buds located at growth areas called
  nodes (leaves, flowers or branches can grow from
  bud at node)
• Terminal bud
• Located at tip of plant
• Controls length
• Lateral buds
• Located on sides of stem
• Controls branch length
• Patterned

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BUD SCALE
TERMINAL BUD
PORE
BUNDLE SCAR
INTERNODE
BUD SCALE SCAR
NODE
LEAF SCAR
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PLANTS

• GROWTH PATTERNS IN STEMS
• ALTERNATE
• Nodes not located at same point on stem
• OPPOSITE
• Nodes located at same level on opposite sides of
  stem
• WHORLED
• Two or more nodes at same level on stem

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PLANTS

• WOODY STEM
• Has primary and secondary tissue
• Bark outer bark cork
• Inner bark cork cambium makes cork
• Cortex, phloem, and vascular cambium
• Functions
• Prevent water loss
• Prevent gases from escaping
• Protect against physical injury parasitic
  invasion
• Conduct food to roots

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PLANTS

• GIRDLING remove ring of bark completely around
  tree kills tree
• WOOD XYLEM
• Annual rings growth rings
• 1 ring 1 years growth
• Springwood lighter color of ring
• Summerwood darker color of ring

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CORK
CORK CAMBIUM
BARK
CORTEX
PHLOEM
2ND YEARS GROWTH
SUMMERWOOD
1ST YEARS GROWTH
SPRINGWOOD
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PLANTS

• MODIFIED STEMS
• RHIZOMES thick, fleshy creeping stems
• Ex. Iris
• TUBERS swollen underground (potato)
• BULBS short, thick leaves (garlic)
• CORM thin, circular leaves (onion)

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PLANTS

• LEAVES
• MOST IMPORTANT MANUFACTURER OF FOOD
• MAKES SUGAR, STARCH, OIL

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PLANTS

• LEAF STRUCTURE
• BLADE flat, thick section used to trap light
• PETIOLE stalk that supports blade, connects
  leaf xylem phloem to stem
• STIPULE found only on some leaves where petiole
  attaches
• MIDRIB main vein of leaf
• MARGIN edge of leaf

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PLANTS
MARGIN
BLADE
MIDRIB
PETIOLE
STIPULE
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PLANTS

• SIMPLE LEAVES one blade one petiole
• COMPOUND LEAVES several blades and several
  petioles
• VEINS can be arranged in various ways
• Pinnate like a feather
• Palmate like fingers on a hand
• Parallel veins lie side by side

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PLANTS

• LEAF TISSUE
• Cuticle waxy layer on top prevents water loss
• Epidermis 1 cell layer thick
• Stomata opening in epidermis
• Allows CO2, oxygen water to pass through
• Regulated by guard cells
• PALISADE LAYER under upper epidermis
• Photosynthesis takes place
• SPONGY MESOPHYLL above lower epidermis
• Air spaces, photosynthesis veins are located

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GUARD CELLS
CHLOROPLASTS
EPIDERMIS
STOMATA
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CUTICULE
UPPER EPIDERMIS
PALISADE LAYER
XYLEM
VEIN
PHLOEM
SPONGY LAYER
LOWER EPIDERMIS
GUARD CELL