Plant Anatomy

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Plant Anatomy

• MUPGRET Workshop
• March 27, 2004

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Definitions

• Anatomy
• Study of form and basic organization.
• Morphology
• Study of tissue organization.
• Physiology
• Study of normal organism function.

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Life Cycle

• Juvenile
• Adult
• Reproductive

Vegetative
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Plant Structure

• Two main organ systems shoot and root
• Shoot
• Above ground
• Leaves, buds, stems, flowers, fruits
• Root
• Below ground
• roots, tubers, rhizomes

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Plant Cells

• Formed at meristems.
• Mitosis in meristem produces new cells.
• Two types of meristems.
• Apical produces primary growth, ex. tip of root
  or shoot.
• Lateral produces secondary growth, ex. cambium.

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Apical Meristem
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Lateral Meristem
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Cells are grouped into tissues.

• Dermal
• Ground
• Vascular

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Cell Types
Epidermal
Ground
Vascular
Zea mays L. leaf cross section
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Dermal Tissue

• Covers outer surface of herbaceous plants.
• Composed of epidermal cells that secrete the waxy
  cuticle.
• Waxy cuticle protects against water loss.

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Ground Tissue

• Bulk of the primary plant body.
• Composed of parenchyma, collenchyma, and
  sclerenchyma.

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Parenchyma
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Parenchyma
pineapple
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Collenchyma
Celery
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Schlerenchyma
hau used to make rope
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Vascular Tissue

• Transports food, water, hormone, and minerals.
• Composed of xylem, phloem, parenchyma, and
  cambium.

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Vascular tissue
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Xylem
Dutchmens pipe
Dicot stem
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Vegetative Structures

• Roots
• Stem
• Leaf

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Roots

• Tap root
• Fibrous root
• Adventitious root
• Tuberous root
• Aerial root

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Roots
Fiberous
Tuberous
Taproot
Taproots
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Stem Anatomy

• Bud undeveloped shoot.
• Node Location of leaf or bud on stem.
• Internode Space between nodes.
• Pith Spongy tissue in the center of the stem.
• Lenticel Pore in the outer layer of the stem.

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Stem
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Stem Modifications

• Tuber underground stem with nodes
• Rhizome underground stem with buds
• Stolon aboveground stem with shoot buds
• Bulb underground stem with fleshy leaves
• Corm underground stem with papery leaves

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Modified Stem
Tendril
Thorn
Onion set
Rhizome
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Modified Stem II
Corm
Asparagus
Stolon
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Growth Form

• Herb
• Shrub
• Tree
• Vine

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Growth Cycle

• Annual single season
• Biennial two seasons
• Perennial multiple seasons
• Evergreen leaves persist gt 2 seasons
• Decidious leaves die in cold or dry

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Leaf Parts

• Petiole
• Blade
• Stipule
• Axillary bud

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Leaf Structure
Blade
Stipule
Petiole
Axillary Bud
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Leaf Arrangement

• Alternate
• Opposite
• Whorled

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Leaf form

• Simple
• Compound
• Pinnate
• Palmate

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Vein Arrangement

• Pinnate
• Palmate
• Parallel
• Dichotomous

Dichotomous
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Leaf Shape

• Ovate
• Elliptic
• Oblong
• Lanceolate
• Linear
• Orbicular

• Cordate
• Hastate
• Sagittate
• Peltate
• Perfoliate
• Terete

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Leaf Margins

• Entire
• Serrate
• Doubly serrate
• Dentate
• Crenate

• Undulate
• Revolute
• Crisped
• Lobed

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Misc. Vegetative Structures

• Thorns
• modified stems (Honey Locust)
• Spines
• modified leaves (Cactus)
• Prickles
• epidermal outgrowth (Rose)

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Reproductive Structures

• Flowers
• Fruits

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Floral Parts

• Pedicel
• Sepal
• Petal
• Perianth
• Stamen
• Carpel
• Pistil

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Flower
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Floral Symmetry

• Actinomorphic
• Many axes of symmetry, ie. the same wherever you
  cut it.
• Zygomorphic
• One axis of summetry, ie. can only cut one way.

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Inflorescence Types
Spadix
Spikelet
Solitary
Spike
Whorl
Panicle
Raceme
Compound Umbel
Umbel
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Fruit Types

• Dry, indehiscent fruit
• Dry, dehiscent fruit
• Fleshy fruit
• Other

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Dry, indehiscent fruits

• Achene (lettuce)
• Samara (maple)
• Caryposis (wheat)
• Nut (almond)

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Dry, Dehiscent Fruit

• Legume (soybean)
• Capsule (tobacco)
• Silique (Arabidopsis)
• Schizocarp (maple)

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Fleshy Fruits

• Drupe (peach, nectarine)
• Berry (tomato)
• Pepo (cucumber)
• Hesperidium (citrus)
• Hip (rose)
• Pome (apple, pear)

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Other Fruit Types

• Aggregate
• mature ovaries from separate pistils of one
  flower (ex. raspberry)
• Multiple
• mature ovaries from separate pistils of several
  flowers (ex. pineapple)
• Accessory
• fruit is something other than ovary tissue (ex.
  strawberry is a swollen receptacle, seeds are
  achenes)

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Placentation
Axile
Marginal
Parietal
Basal
Free central
Apical
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Ovary Position
Hypogynous (above calyx)
Perigynous (within the floral cup)
Epigynous (below calyx)
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Monocots vs. Dicots

• One cotyledon
• Parallel leaf veins
• Flower parts often in multiples of three
• Vascular bundles scattered in stem

• Two cotyledons
• Netlike leaf veins
• Flower parts often in multiples of 4 or 5
• Vascular bundles in a ring in the stem