22.2 reproduction in flowering plants teks 6g, 10b the student is expected to: 6g recognize the...
TRANSCRIPT
22.2 Reproduction in Flowering Plants TEKS 6G, 10B
The student is expected to:
6G recognize the significance of meiosis to sexual reproduction
and
10B describe the
interactions that occur among
systems that perform the functions
of transport, reproduction, and
response in plants
22.2 Reproduction in Flowering Plants TEKS 6G, 10B
KEY CONCEPT Reproduction of flowering plants takes place within flowers.
22.2 Reproduction in Flowering Plants TEKS 6G, 10B
sepal
Flowers contain reproductive organs protected by specialized leaves.
• Sepals and petals are modified leaves.– Sepals are outermost
layer that protectsdeveloping flower
22.2 Reproduction in Flowering Plants TEKS 6G, 10B
– Petals can help to attract animal pollinators
petal
22.2 Reproduction in Flowering Plants TEKS 6G, 10B
• A stamen is the male structure of the flower.
– anther produces pollen grains – filament supports the anther
stamen
filament anther
22.2 Reproduction in Flowering Plants TEKS 6G, 10B
carpel style
stigma
ovary
• The innermost layer of a flower is the female carpel.
– stigma is sticky tip – style is tube leading from stigma to ovary – ovary produces female gametophyte
22.2 Reproduction in Flowering Plants TEKS 6G, 10B
Flowering plants can be pollinated by wind or animals.
• Flowering plants pollinated when pollen grains land on stigma.
• Wind pollinated flowers have small flowers and large amounts of pollen.
22.2 Reproduction in Flowering Plants TEKS 6G, 10B
• Animal pollinated flowers have larger flowers and less pollen.
pollen grains
– many flowering plants pollinated by animal pollinators
– pollination occurs as animal feeds from flower to flower– animal pollination more efficient than wind pollination
22.2 Reproduction in Flowering Plants TEKS 6G, 10B
Fertilization takes place within the flower.
• Male gametophytes, or pollen grains, are produced in the anthers. – male spores produced in
anthers by meiosis– each spore divides by
mitosis to form twohaploid cells
– two cells form asingle pollen grain pollen grain
22.2 Reproduction in Flowering Plants TEKS 6G, 10B
– four female spores produced in ovule by meiosis – one spore develops into female gametophyte – female gametophyte contains seven cells – one cell has two nuclei, or polar nuclei – one cell will develop into an egg
• One female gametophyte can form in each ovule of a flower’s ovary.
22.2 Reproduction in Flowering Plants TEKS 6G, 10B
• Pollination occurs when a pollen grain lands on a stigma.
pollen tubepollen tube
spermsperm
stigmastigma
– one cell from pollen grain forms pollen tube– other cell forms two sperm that travel down tube
22.2 Reproduction in Flowering Plants TEKS 6G, 10B
• Flowering plants go through the process of double fertilization.
femalegametophyte
ovule
egg
sperm
polar nuclei
22.2 Reproduction in Flowering Plants TEKS 6G, 10B
endosperm
seed coat
embryo
– one sperm fertilizes the egg
– other sperm unites with polar nuclei, forming endosperm
– endosperm provides food supply for embryo
• Flowering plants go through the process of double fertilization.
22.2 Reproduction in Flowering Plants TEKS 6G, 10B
• Each ovule becomes a seed.• The surrounding ovary grows into a fruit.