Transcript Botany Ch8 Flower Anatomy PPT

Chapter 8
Lecture Outline
Flowers, Fruits, and
Seeds
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Outline

Introduction-- Reproductive Organs

Phylum Anthophyta-- Differences Between
Eudicots and Monocots

Structure of Flowers

Fruits

Fruit and Seed Dispersal

Seeds
INTRODUCTION--REPRODUCTIVE ORGANS

Sexual Reproduction

Primitive Reproductive Organs
• Archegonia
• Antheridia
• Sporangia

Complex Reproductive Organs of the Higher
Plants
• Cones
• Flowers of Angiosperms
PHYLUM ANTHOPHYTA--Eudicots and Monocots

Two major classes of flowering plants:
•
Eudicots (Magnoliopsida) and Monocots (Liliopsida)
Dicots
Monocots
Two cotyledons
One cotyledon
Flower parts in multiples of four
or five
Flower parts in multiples of three
Leaves with distinct network of
veins
Leaves with parallel primary veins
Vascular cambium and cork
cambium present
Vascular cambium and cork
cambium absent
Vascular bundles of stem in ring
Vascular bundles of stem scattered
Pollen grains with three
apertures
Pollen grains with one aperture
Structure of Flowers

Flowers begin as embryonic primordium

PARTS
Peduncles.
•

pedicels
Receptacle - Swollen end of peduncle or
pedicel
Other parts of flower attached to receptacle in whorls:
sepals, petals, stamens, and pistil.
Structure of Flowers

Sepals - Outermost whorl
• calyx
• function

Petals - Next whorl inside sepals
• corolla
– Function of Showy corollas:
– Inconspicuous or missing corollas in plants that are:
• Calyx and
corolla
form
perianth.

Stamens attached around base of pistil.
• filament
• anther
–

Pollen grains developed in anthers.
Pistil = female portion:
• Ovary:
–
Ovules
• Style:
• Stigma:
OVARY …
–
Superior Ovary –
–
Inferior Ovary
–
Ovary with ovules.
–
o
Seeds develop from:
o
Fruit develops from:
Simple or Compound Ovary:
Inferior Ovary …
Structure of Flowers

Flowers can be produced singly or in
inflorescences.
• Inflorescence
–
Spike:
–
Raceme:
–
Panicle:
–
Umbel:
–
Compound
Umbel:
–
Head:
–
Catkin:
Fruits

Fruit =
• develops from:
• And from Accessory parts:

Phylum of Plants w/ fruits:
Tomato
fruit
Fruit Anatomy

Pericarp: Three
regions
collectively

Fruit Regions
• Exocarp:
• Endocarp:
• Mesocarp:
Peach fruit

Variability of fruits
• fleshy or dry
•
Formed from one or more flowers
Milkweed follicle
Types of Fruits

Fleshy Fruits:
• SIMPLE FLESHY FRUITS: # PISTILS
–
Drupe:
• single seed
• enclosed by
hard, stony
endocarp (pit)
Drupes: peaches,
almonds, olives
Simple fleshy fruits …
–
Berry
– Pericarp: __________
– Ovary: ______________
– # seeds _______
– True berry - thin skin and
soft
o Examples:
– Pepo - Relatively thick rind
o Examples
– Hesperidium – leathery skin
has citric acid glands
o Examples
Grape berries
–
Pome - receptacle
grows:
o Endocarp papery or
leathery
o Apples, pears
Apple pomes
Fruits

Complex Fleshy Fruits
• Aggregate Fruits
– Derived from single
flower with several to
many pistils
o Examples
Blackberry aggregate fruits
•
Multiple Fruits
- several to many
individual flowers in
single inflorescence
–
Mulberries, Osage
orange, pineapples,
figs
Osage orange multiple fruit
Fruits

Dry Fruits - Mesocarp dry at maturity
• Dehisicent or indehiscent
• DEHISCENT FRUITS
• Follicle - Splits
along one side
–
Larkspur,
milkweed, peony
• Legume - Splits
along two sides
–
Legume family:
peas, beans,
lentils, peanuts
Milkweed follicle
Legumes
Fruits

Dehiscent fruits …
•
Siliques:
•
More than three
times longer than
wide
•
Examples:
Silique
Silicle
Fruits

Dehiscent fruits …
•
Capsules – split in:
•
Examples:
Capsules
Fruits

Dry Fruits

INDEHISCENT FRUITS =
• Single seed: united with
pericarp
–
–
Achene - Base of seed
attached to pericarp.
o Examples
Nut - harder and thicker
pericarp with:
o Examples:
Inside of
sunflower
achene
Acorn
Fruits

Indehiscent Fruits
• Grain (Caryopsis) - Pericarp tightly
united with seed
–
Examples:
• Samara - Pericarp extends
Corn section
as:
–
Examples:
• Schizocarp - Twin
fruit
• Examples
Samaras
Schizocarp of mericarps

FLESHY
• Simple
• Aggregate
• Multiple
• DRY
–
Dehiscent
–
Indehiscent
Fruit and Seed Dispersal

Dispersal by Wind
• Fruits and/or seeds
have:
Fruit and Seed Dispersal

Dispersal by Animals
• 2 Main Types
–
Dispersal by Animals …
• Oils attract ants.
– Elaiosomes on bleeding
hearts used as food by ants.
Seeds from bleeding hearts.
Elaiosome is white.

Water Dispersal
• Some fruits contain trapped air for floatation.

Structure
Seeds
• Ovules develop into seeds.
–
Cotyledons - Food storage organs that function as
“seed leaves”
–
Embryo = cotyledons and plantlet
Bean seed
Germination

Germination =
• Fruit Ripe when – after embryo develops.
Germination …


Favorable environmental factors needed for
germination.
•
W
•
O
•
L
•
T
Enzymes activated by:
Germination
• Some require period of dormancy.
–
Period of Cold
–
Mechanical Abrasion
o
–
Scarification:
Growth-inhibiting substances present in seed coat or
fruit– that must be washed off by rain
Longevity

Seed viability varies,
depending on species
and storage conditions.
• Viability extended:
–
Temperatures
–
Wet or Dry?