Fruits & Flowers
Chapter 6 Overview
Chapter 6 Overview
http://www.ddflowers.com.sg/Products/Thumbnail/192-GW016-LO.JPG
What are fruits & flowers for?
• When you bite into a juicy peach or when
you give someone a bouquet of daisies or
roses- you probably aren’t thinking:
“ Wow, these are marvelous structures
designed to facilitate effective sexual
selection & maximize reproductive
success in angiosperm plants!”
• From now on- this is what you should be pondering!
Plant reproduction is complex
• Unlike humans, who reproduce only
sexually, with a single method, plants
have a variety of ways of reproducing.
• Asexual
• Sexual
Asexual Reproduction:
• Also known as ‘ vegetative
propagation”
• Offspring are clones of parent
• Genetically identical
• Cell division by mitosis
Review: Stages of Mitosis
Divided into 4 phases:
1. PROPHASE
2. METAPHASE
3. ANAPHASE
4. TELOPHASE
•
Memory aid: Pro met Anna on the telophone
http://jabberwiki.wikispaces.com/file/view/mitosis1.gif/53565174
Can you find a cell in each phase of mitosis?
http://www.bioweb.uncc.edu/1110Lab/notes/notes1/labpics/Onion%20Prophase%20and%20%20Metaphase%2020x.jpg
Example of Plant asexual reproduction:
1. Strawberry
plants- sends
out stolons
or runners
• Only need a
few plants to
start a
strawberry bed.
http://www.smallkitchengarden.net/wp-content/uploads/c37d59f25bed5e2.jpg
Examples of Plant
asexual reproduction:
2. Kalanchoe diagremontiana
“walking fern” plant
• Produces “plantlets”
on the edges of leavesa leaf that touches the
ground grows into a
new plant
http://pics.davesgarden.com/pics/WUVIE_1189126100_673.jpg
Example of Plant asexual reproduction:
3. Quaking
aspen trees
• Adventitious roots
make a large group of
trees
• The whole group is
called a “clone”
http://www.coloradotreefarmnursery.com/photogallery/Deciduous%20Trees/Aspen/Aspen%201/Aspen.jpg
Sexual reproduction in plants
• Sexual reproduction uses process of
Meiosis
• Gametes- are Haploid cells
– Spores, Sperm (pollen), eggs (ovule)
• Form a Zygote – the fertilized egg
• Genetic recombination of genes produces
a unique individual.
Review: Sexual Reproduction
in plants has “Alternation
of generations”
• life cycle with 2 different generations.
• a Haploid Gametophyte produces
gametes.
• Gametes unite and give rise to a
Diploid Sporophyte, which produces
spores or haploid cells
Alternating Life Cycles
REVIEW: In flowering seed plants angiosperms:
• 2 fertilization events take place:
– one sperm fertilizes the egg to form the
diploid zygote of the new individual,
– the other sperm fertilizes the polar
nuclei to form the triploid endosperm, a
nutritive tissue (the FRUIT).
• Together with maternal sporophyte
tissue, these make up the seed.
Flowers, fruit & seeds
• Only in angiosperm plants
• With nearly 250,000
species- there is great
variety in flower structure
• All flowers sit at the top of
the stem part called the
peduncle
http://content.answers.com/main/content/img/Gardeners/f0186.jpg
Inflorescence
• A peduncle bearing a group of flowers
• Several different types shown below:
http://www3.hcs.ohio-state.edu/wiki/images/d/d2/Inflor.GIF
Flowers
• highly specialized reproductive
organs,
• reproductive functions include:
– Advertising (attracting pollinators)
– pollination
– fertilization
– seed development
– Seeds dispersal
Parts of a flower
Male parts:
-stamen
Female parts:
-Carpel, also
called pistil
2 other modified
leaves:
-Sepals
-Petals
http://andromeda.cavehill.uwi.edu/Plant%20Propagation%20Practical%20Photos/Generalised_Flower_Diagram.jpg
Complete & Incomplete Flowers
• Compete flower - if it contains all
four types of modified leaves :
– Sepals
– Petals
– Stamens
– Carpels
• Incomplete Flowers - lack one or
more of these modified leaves
Perfect flowers
• Perfect- also known as bisexual
flowers have both male (stamens) &
carpels (pistil) parts on same flower.
– Roses
– Olives (also has staminate flowers)
– Apples
– Cherries
– Nectarines
Imperfect- unisex flower
• Has either stamen or carpel (pistil) –not both
• Has only one set of reproductive organs
• Two types of imperfect flowers (either male
or female)
–Staminate flowers contain only stamens,
the male reproductive part of the flower.
–Pistillate flowers only contain the pistil, or
female, reproductive
Flowers have ovaries in different
positions:
• The location of the ovary to the sepals &
petals:
*Superior
*Semi-Inferior
*Inferior
Types of plants:
• Monoecious plants have male and
female parts on the same plant
• (corn, cucurbits, birch, walnut).
• Dioecious plants have male and
female flowers on separate plants
• (hemp, American holly, hazel nut).
Apples have perfect flowers
• Green sepals (6) protect the bud
before the flower opens.
• Petals (1) white, -are highly
visible to the insect pollinators.
• Male parts -filament (5) and
anther (4). Pollen is produced in
its anthers
• Female parts: stigma (2), style &
ovary (7)).
• Pollen land on the stigma, forms a
pollen tube that grows down the
style (3) to the ovary (7), where it
releases the male gamete &
fertilizes the ovule in the ovary.
• The fertilized ovule develops into
a seed and the ovary typically
develops into the fruit.
quorumsensing.ifas.ufl.edu/HCS200/Breefrme.html
Blackberries have perfect flowers
www.cobaltinc.com/.../Classify/classifi.htm
How to Identify Male and Female
Zucchini Flowers
Female Flower
Male Flower
Imperfect
flowers:
Hazelnutseparate male
& female flowers
on same plant
Grasses -monocots
• flowers of grasses are less
showy (“fescue flower”).
• 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).
quorumsensing.ifas.ufl.edu/HCS200/Breefrme.html
Fruit:
• is a ripened (mature) ovary
• Where seeds develop & are
found
• serves as protection
• Means of dispersal for the
seeds
http://biology.clc.uc.edu/courses/bio106/angio.htm
Some types of fruits:
Simple fruits
-from one ovary in
one flower.
Examples: walnut, tomato, orange, cherry,
apple, dandelion, and maple “helicopter.”
-Different types of simple fruit-
each has its own official name.
Aggregate fruits arise from
several ovaries in one flower. Examples
include raspberry and strawberry.
Multiple fruits arise from ovaries in several,
tightly-clustered flowers which grow together into one “fruit.”
Examples include pineapple, mulberry, and breadfruit.
http://biology.clc.uc.edu/courses/bio106/angio.htm
Some activities:
• Fruits game
• Dissect flower
Your assignment:
1. Read Ch 6
2. Section review questions
Page 130, # 1 & 3
Page 134 # 1- 3
Page 143 # 1- 3
3. Read pages 137 & 138 - boxes about
Apomixis, & Tropical Fruits
4. Page 144, Thought question: #1