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Ch:10 Flowers and Reproduction - Coggle Diagram
Ch:10 Flowers and Reproduction
Concepts
producing genetically different individuals
producing offspring with identical copies of parental genes
Asexual Reproduction
Fragmentation
Individual part become self sufficient by growing adventitious roots
For ex: willows , thistles
different methods of asexual reproduction have evolved
Sexual Reproduction
angiosperms involve flowers
The plant life cycle
Sporophyte generation
are always diploid
have organs located in flowers
haploid spores is produced by meiosis
Gametophyte generation
formed after mitosis of spores
produces gametes
can undergo syngamy to produce zygote
alternation of generation occurs
Flower structure
no secondary growth
never become woody
stalk is pedicel and has receptacle
complete flowers has all 4 floral appendages
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incomplete flower las one or two floral appendages
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For ex: Flowers of
Begonia
Sepals
Lowermost and outermost floral appendages
modified leaves that enclose flowers
are colorful and has calyx
Petals
located above sepals
make up corolla
sepals+petals=perianth
produces volatile fragrances
Stamens
located above petals
collectively known as androecium
has filament and anther
microsporocytes undergo meiosis to produce microspores
Carpels
has gynoecium
has stigma, style and ovary
has placenta that has ovules in it
ovules has parenchymal cells called nucellus
has megasporocytes
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Gametophytes
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Microgametophyte
microspores develop into microgametophytes.
microspores divide mitotically to produce vegetative cell and generative cell.
generative cells forms sperm cells.
Megagametophyte
megaspores develop into megagametophyte
multinucleate megagametophyte is called embryo sac.
has one large cell with two polar nuclei, 3 antipodal cells and an egg apparatus with two synergids.
Fertilization
syngamy is fusion of egg and sperm.
fusion of nuclei is karyogamy
angiosperms undergo double fertilization
Embryo and seed development
zygote develops forming a suspensor
forms two cotyledons
embryo cotyledons gives a heart shape.
forms monocots and dicots
in torpedo stage radicle, epicotyl and hypocotyl forms
Seeds
Albuminous seed
has abundant endosperm
exalbuminous
endosperm is sparse or lacking
integuments surrounding nucellus become seed coat.
Fruit Development
matured ovary
three layers
exocarp
skin or peel
mesocarp
flesh or innermost layer
endocarp
pit of cherry
pericarp is having all three layers
Flowers Structure and cross pollination
Cross-Pollination
pollination by different individuals
self pollination
pollination by pollen from same plant
Stamen and Style maturation
self fertilization on flowers have both stamens
older flowers being pollinated by younger flowers.
Stigma and pollen incompatibility
in crop species, self pollination is inhibited
compatibility barriers
prevention of pollen growth by chemical reaction in carpel
protein produced by incompatibility gene blocks germination.
Monoecious and dioecious species
imperfect flowers
lacking either or both stamen and carpels
perfect flowers
if it has both stamen and carpels.
dioecy: only either stamenate or carpellate flowers
also called dioecious plant
for ex: marijuana plant, papaya, dates etc.
monoecy: having staminate flowers on the same plant as carpellate flowers
For ex: melons, squash, pumpkin plants
Animal -Pollinated Flowers
fragnance, nectar colorful petals are adaptation
undergo coevolution with plants
actinomorphic flowers: radially symmetric flowers
zygomorphic flowers: bilaterally symmetrical
does not provide selection advantage
Ovary position
ovary and ovules must be protected
inferior ovary : receptacle tissues grows around ovary
superior ovary
ovary is above the other parts of flowers
Inflorescences and Pollination
any flowers group together
visual signal to pollinators
arrangements
determinate inflorescences
limited growth
indeterminate inflorescences
outermost flower opens first
For ex: Catkins, receme
Fruit Types and seed dispersal
adaptation for protection and seed dispersal
True fruits and accessory fruits
True fruit
containing ovarian tissue
accessory fruit
non ovarian tissue
for ex: strawberry
Simple fruit
fruit developed from single ovary
aggregate fruit
fruit developed from separate carpels of one gymnosperm
multiple fruit
all inflorescences fused into one fruit
For ex: figs, mulberries, pineapples
Dehiscent fruit
release seed by breaking open
indehiscent fruit
fleshy fruit that do not break open
