Download Reproduction and Domestication of Flowering Plants

Reproduction and
Domestication of Flowering
Plants
Pollination - wind, insects birds
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transfer of pollen from an anther to the
stigma of a carpel
Pollen tube is formed when pollen lands on
stigma
Double fertilization – 1 sperm nucleus
unites with the egg nucleus  2n zygote 
mitosis to form embryo
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Other sperm nucleus unties with polar nuclei of
central cell and forms 3n endosperm cell
Endosperm nourishes embryo and seedling
during development
Mutualism and Coevolution
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Many species of flowering plants have
evolved with specific animal pollinators
– mutualism
The joint evolution of two interacting
species, each in response to selection
imposed by the other – coevolution!
Flower parts
Flower parts
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sepal – green, protects bud
Petal – specific to pollinator, wind pollination may
not have flowers
Stamen – male
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anther -pollen grains produced here from microspores
filament
Carpel – female
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Stigma – sticky knob
Style - stalk
Ovary – base, contains ovules
Ovary = Fruit
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Contains ovules, which develops into
seeds.
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Fruit protects the seeds and
aids in their dispersal by
wind and animals.
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Seeds
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As seed matures, it enters dormancy
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Low metabolic rate, growth and
development suspended
Resumes growth under good
conditions,
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fire, rain temperature can break
dormancy
Seed Germination
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Imbibing water causes seed to expand
and rupture seed coat and triggers
growth
Timing and coordination of breaking
seed dormancy and initiation of
germination is important.
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Environmental cues and cell signaling
Flowering plants reproduce
sexually or asexually or both
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Asexual reproduction is called
vegetative reproduction – clones
Self fertilization
Grafting, cuttings, test tube cloning
For genetic variation, plants can have
self – incompatibility – rejects own
pollen
Genetic Engineering with
plants
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Artificial selection
Conversion of plant material to sugars
to make alcohols and distilled to yield
biofuels.
GMO’s – golden rice