Monocots vs. Dicots
Primitive vs. Advanced Flowers
Stems, Leaves, and Roots
Plant Structure Resource

http://faculty.clintoncc.suny.edu/faculty/m
ichael.gregory/files/bio%20102/Bio%201
02%20lectures/Plant%20Structure/plant
%20structure.htm
Flower structure
No two species of
plants have
identical floral
anatomy, but the
following
diagrams illustrate
"typical" flowers
with both male and
female parts.
Primitive Versus Advanced Floral Characteristics
Primitive
– Flower parts many, more
than ten
– Flower parts free (not
united or fused)
– Superior ovary
– Flowers with radial
symmetry
Advanced
– Flower parts few, ten or less
– Flower parts united or fused
– Inferior ovary
– Flowers with bilateral
symmetry
Angiosperms’ Life Cycle
Angiosperm Adaptations
Dehydration – broad and deep roots reach water at
greater depths and distances; waxy cuticle on leaves;
stomata prevent water loss during gas exchange; lose
leaves during extreme cold and become dormant;
 Nutrient/Waste Exchange - photosynthetic; vascular
tissue
 Gamete Transmission – Reproduce without water to
transmit male gamete; pollination aided by wind, insects,
birds, and bats; pollen gets trapped by sticky stigma; selfpollination in some species; fruit offers protection to
developing seed.
 Structural Support – vascular tissue, strengthened by
special chemicals, allow these to reach heights
unattainable by nonvascular plants; deep roots help
anchor
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Plant Structures
Flower to Fruit
Fruits/Seeds
Angiosperms
Diversity
 Monocotyledons
 dicotyledons
Distinguish the identifiable features of
Monocots vs. Dicots
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MONOCOTS
Embryo with single cotyledon
Pollen with single furrow
or pore
Flower parts in multiples
of three
Major leaf veins parallel
Stem vascular bundles scattered
Vascular cambium absent
Roots are adventitious
Secondary growth absent
present
DICOTS
*Embryo with two cotyledons
*Pollen with three furrows or
pores
*Flower parts in multiples of four
or five
*Major leaf veins reticulated
*Stem vascular bundles in a ring
*Vascular cambium present
*Roots develop from radicle
*Secondary growth often
Plant tissues
 Ground
tissue
 Vascular tissue
 Dermal tissue
 Cuticle
Vascular Tissue
Monocot vs. Dicot Stems
Monocot vs. Dicot Root
Monocot vs. Dicot Leaf
Stomata allow Transpiration
 Transpiration
assists
photosynthesis in 2 ways:
1. “Transpiration pull” moves water,
minerals and other substances from
the roots to other plant parts (aka
Capillary Action)
2. Transpiration cools the leaf by
evaporation so enzymes required to
catalyze reactions are not denatured.
Leaf – page 503-507
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Stomata – pores found mostly in leaves and less so in stems;
responsible for regulation of carbon dioxide, oxygen exchange
with atmosphere (needed for photosynthesis) and water loss
(transpiration)
Guard cells – regulate the opening and closing of stomata by
changing size due to water moving in and out by osmosis
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Open when cells
are turgid
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Closed when cells
are flaccid
Stems/Trunks – pages 518-523
woody
 Annual ring
 Cork
 Phloem/xylem
 Cambium
 Sapwood
 heartwood
Herbaceous
 Epidermis
 Endodermis
 Cortex
 Xylem/phloem
 pith
Comparison of Stems
Root System – pages 512-515
Tap roots
 Fibrous roots
 Adventitious roots
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Transport in Plants
Transpiration
 Translocation
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Responses in Plants
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Hormones
 Auxins
 Giberellins
 Cytokinins
 Ethylene
 Abscisic Acid
Tropisms
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Tropisms
 Positive
 Negative
 Nastic movements
 Phototropism
 Geotropism
 Thigmotropism
 Photoperiodism
Resources
Discover Life
 Angiosperm Flowers
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Review of flower anatomy and
pollination
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Flowers are highly specialized
reproductive organs, adapted for the
entire range of reproductive functions:
advertising, pollination, fertilization, seed
development, and dispersal of seeds.
Flowers can be male, female or both.
 By far the most common arrangement is
having both male and female parts
within each flower, otherwise known as
perfect flower.
 Imperfect flowers have either male or
female parts.
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Monoecious plants have male and
female parts on the same plant (e.g.,
corn, cucurbits, birch, walnut).
 Dioecious plants have male and female
flowers on separate plants (hemp,
American holly, hazel nut).
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Complete flowers have all four parts
(sepals, petals, stamen and pistil), while
incomplete flowers are missing one or
more of these parts.
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No two species of plants have identical
floral anatomy, but the following
diagrams illustrate "typical" flowers with
both male and female parts.
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Apple (above) has a perfect flower. Green
sepals (6) protect the bud before the
flower opens. Petals (1) which people see
as white, are highly visible to the insect
pollinators. Male parts of the flower are
called stamens, and consist of a filament
(5) and anther (4). Pollen is produced in its
anthers (4). When pollen grains mature,
they land on the stigma (2), which is a
receptacle for the style (a long tube that
empties into the ovary (7)).
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The pollen grain then forms a pollen
tube that grows down the style (3) and
reaches the ovary (7), where it releases
the male gamete. The gamete proceeds
down the tube to fertilize an ovule in the
ovary. The fertilized ovule develops into
a seed and the ovary typically develops
into the fruit.
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Sepals and petals in flowers of tulip
(right), and its monocot relatives (lilies,
daffodils, onions, etc) evolved into one
organ, sometimes referred to as "tepal"
(8, right). Flower parts of tulip are
labeled similarly to the flower parts of
apple.
Grasses
Grasses are also monocots. You'll notice
that flowers of grasses are less showy
(eg. fescue flower, left).
 Grasses typically produce significant
amounts of pollen in their anthers (4).
 Carried by wind, pollen lands on sticky
feather-like stigma receptacles (2).
 Sepals and petals of grasses have
evolved into three layers of protective
bracts -glume, palea, and lemma (9).
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