Ch. 38 Flashcards
What is Mutualistic Association?
When plants and other species use various mechanism to benefit each other
How do angiosperms attract insects?
nectar or pollen (both plant and pollinator benefit)
symbiotic
living together
What are flowers?
Reproductive shoots of angiosperm sporophytes
what part of the plant do flowers attach to?
receptacle
What are Stamens and Carpels?
Sporophylls (leaves specialized for reproduction)
What are Sepals and Petals?
Sterile modified leaves
What are Carpels?
Contains a long STYLE with sticky STIGMA on top that captures pollen
Megasporophyll (female part)
What do fertilized Ovules create?
Seeds
What is at the base of a style?
An ovary with one or more ovules
What is a Simple Pistil
Made up of one Carpel
Pistil
Single carpel or group of fused carpels
What is a compound pistil
Made up of more than one Carpel
What is a stamen
Consist of an anther and filament
Microsporophyll (male)
What does anther contain?
Pollen sacs (microsporangia) that makes pollen
What are Sepals? (2)
1) They enclose and protect unopened floral buds
2) Structures that resemble leaves
What are Petals?
Usually brightly colored to attract pollinators
What makes up a complete Flower?
a flower that contains all four floral Organs
What makes up an incomplete flower?
a flower that lacks one or floral organs
What do Sterile Flowers lack?
Stamens and Carpels
What do unisexual flowers lack?
Either a Stamen or a Carpel
Inflorescences
Cluster of flowers!
what is pollination
the transfer of pollen from anthers to stigma
can occur by wind, water, or animals
which type of pollination do most angiosperm rely on?
animal pollination
Wind pollinated characteristics? (2)
1) Release large amounts of pollen
2) Small flowers without nectar and scent (no attraction)
Moths and Butterflies pollination characteristics?
1) Flowers usually have sweet fragrance
2) Butterfly flowers are bright colors
3) Moth flowers are white and yellow
Flowers relying on Bat pollination characteristics
Flowers are light colored and aromatic
flowers relying on Bee pollination characteristic (2)
1) typically brightly colored
2) sweet fragrance
Fly pollination characteristic
1) Flowers smell like rotten meat
flowers relying on bird pollination characteristics (3)
1) Flowers are usually large, bright red or yellow
2) Low oder and large quantities of nectar
3) Petals fused into a floral tube
what are nectar guides?
ultraviolet markings that direct bees and other insects to nectar-producing glands
angiosperm life cycle characterized by 3 F
Flowers, double Fertilization, Fruit
The angiosperm life cycle includes
1) gametophyte development
2) sperm delivery by pollen tube
3) double fertilization
4) seed development
What is Androecium?
All the stamens of the flower
What is Gynoecium
The female part of a flower
consisting of one or more carpels (same as pistil)
Ando
Males
Gyn
Female
What is an embryo sac?
Female gametophyte that develops in the ovule
What is micropyle?
A pore between the two integuments that surrounding the megasporangium
How many megaspores does one MEGASPOROCYTE produce after meiosis?
4 megaspores only one survive
How many haploid nuclei are in one cell after a megaspore divides?
8 nuclei are created without cytokinesis
What happens to the cell that gets partitioned?
It turns into a multicellular female gametophyte, the embryo sac
cyt
cell
kinesis
movement
Each microspore undergoes mitosis to produce how many cells?
2 (one generative cell and one tube cell)
What does the pollen grain consists of?
Two-celled male gametophyte and the spore wall
What produces a pollen tube?
When a pollen grain lands on a receptive stigma and two sperm cells are discharged near the embryo sac
When does fertilization occur?
After two sperm reach the female gametophyte
What does the two sperm in double fertilization do?
One fertilizes the egg
One combines with two polar nuclei, creating triploid endosperm
What does double fertilization do?
Ensures that endosperm only develops in the ovules containing fertilized eggs
What happens after double fertilization?
1) Each ovule develops into a seed
2) The ovary develops into a fruit
What happens to the ovary after double fertilization?
Develops into a fruit enclosing the seed
What happens when a seed germinates
The embryo develops into a sporophyte
What does a mature seed consists of
1) Dormant embryo
2) Endosperm (stored food)
3) seed coat
characteristics of the first mitotic division of the zygote (2)
1) Asymmetrical
2) Splits fertilized egg into a basal cell and terminal cell
carp
fruit
What does a basal cell produce
Suspensor, which anchors the embryo to the parent plant and aids in nutrient transfer to the embryo
which develops first: endosperm or embryo
endosperm
What does seed coat do?
encloses the embryo and its food supply
what is the endosperm?
nutrients storage place of the seed
5 steps to embryo development
1) first mitotic division of zygote (basal and terminal cell)
2) basal cell produces suspensor
3) terminal cell give rise to embryo
4) cotyledons form
5) embryo elongates
Whats below the cotyledons, embryonic axis? Whats above?
below: Hypocotyl and radicle
above: epicotyl
What does plumule have?
Comprises of the epicotyl, young leaves, and shoot apical meristem
What happens when a seed dehyrdates
It enters a state of dormancy
Grasses, such as maize and wheat, have a special cotyledon called a _______
scutellum
What does the terminal cell do?
gives rise to most of the embryo
What two sheathes enclose the embryo of a grass seed?
1) Coleoptile covering the young shoot
2) Coleorhiza covering the young root
Coleo
sheath
ptile
feather or wing
What are benefits of seed dormancy?
Increases the chance that germination will occur at a time and place most advantageous to the seedling
How does a seed exit seed dormancy?
Requires specific environmental cue like temperature and lighting change
What happens after seed germination?
Growth of roots, stems, leaves, and flowering
What is imbibition?
The uptake of water due to low water potential of the dry seed
Germination depends on imbibition
steps to seed germination (eudicots)
1) The radicle emerges
2) shoot tip breaks surface
3) hook forms in hypocotyl
4) growth pushes hook above ground
5) light causes hook to straighten pulling the cotyledon and shoot tip up
what does the radicle do?
develops root system that anchors plant and provides water
What does the coleoptile do in monocots?
In monocots it pushes up the through the soil creating a tunnel for the shoot tip to grow from
What promotes outbreeding?
Flowers are synchronized to appear at a specific time of the year
What triggers flowering?
Environmental cues and internal signals
What is a fruit?
Mature ovary of a flower
Protects the enclosed seeds and aids in dispersal
What is a simple fruit?
Develop from a single or several fused carpels
What is an Aggregate fruit?
Results from a single flower with separate Carpels
What is Multiple Fruits
Develop from group of flowers (inflorescence)
What are accessory fruits?
Contains other floral parts in addition to ovaries
What does fruit dispersal ensure?
That seeds germinate away from the competitve influence of the parent plant
What is asexual reproduction?
Produces offspring without fusion of egg and sperm
Offspring is a clone
What is fragmentation?
Seperation of a parent plant into parts that develop into whole plants
What is apomixis?
Asexual production of seeds from a diploid cell
What is vegetative reproduction?
Asexual reproduction
When progeny arise from mature vegetative fragments
These progeny are more resilient than seedlings produced by sexual reproduction
What is selfing?
1) When flowers self fertilize to ensure that every ovule will develop into a seed
2) Reduces genetic diversity
What do Dioecious species do to prevent selfing?
different plants either have
1) Staminate flowers (lacking carpels)
2) Carpellate flower (lacking Stamens)
4 ways flowers prevent selfing?
1) Have stamens and carpels mature at different times
2) Spatially arranged to prevent selfing
3) Dioecious species
4) self-incompatability
What is self-incompatibility?
1) Plants ability to reject its own pollen
2) Recognizes self pollen based on S-genes
