UCM GenBioII Final - Plant Reproduction

Biphasic lifecycle

• diploid sporophyte

• haploid gamete

Biphasic lifecycle steps

1) Cells in sex organs of sporophyte undergo meiosis, producing haploid spores

2) Spores develop into haploid gametophyte(s) via mitosis

3) Gametophyte(s) produce haploid sperm and egg

4) Sperm and egg fuse, forming a diploid zygote

5) Zygote develops into sporophyte via mitosis

dioecious

entire plant is either male or female

• males produce staminate flowers

• females produce ovulate flowers

ex) cycads, conifers, some flowering plants

monoecious

plant has both male and female reproductive parts

• some produce separate male and female flowers

• some produce male and female reproductive structures on the same flower

ex) most flowering plants

sepals

modified leaves that protect the developing flower bud

petals

modified leaves that attract pollinators

stamens

male parts

• anthers = contain microsporangia

• filaments = support the anthers

carpel

AKA gynoecium

• stigma = where pollen is deposited

• style = pollen tube grows down the sole branch to the ovaries

• ovaries = contain megasporangia

microspores

• male gametophyte = pollen grain

• produce two sperm cells that will travel on the pollen tube

megaspores

• female gametophyte

• produce four megaspores (3 degenerate)

• three mitotic divisions = eight-celled female gametophyte

• three antipodal cells

• two synergic cells

• egg at the bottom

• day or night

• dull-colored flowers

• no smell

• no petals

• lots of lightweight pollen

• no pollinator reward

wind pollination (anemophily)

• day or night

• dull-colored flowers

• no smell

• no petals

• lots of heavy pollen

• no pollinator reward

water pollination (hydrophily)

• bowl shaped or clusters

• white, dull white, green, or colorful

• fruity or spicy smelling

• many stamens with lots of pollen

• pollen or food bodies are the reward

• day-active

beetle pollination (cantharophily)

• day active

• large, bowl-shaped or broad

• vivid colors

• landing platform

• tube-shaped flowers

• no smell

• nectar is the reward

non-hummingbird bird pollinators

• narrow tubes projecting to the side or down, small

• red, orange, yellow

• no landing platform

• no smell

• nectar is the reward

• day-active

humming bird pollination

• color variable

• nectar guides may be present

• see, perfume, or fruity smell

• flowers are a deep, narrow tube or many small tubes

• reward is nectar

• landing platform usually

• day-active

butterfly pollination (psychophily)

• white, pale green, pale yellow

• sweet, perfume, or fruity smell

• smell strongest at night

• flower is a deep tube or series of small tubes

• reward is nectar

• landing platform can be present or absent

• night-active

moth pollination (phalaenophily)

• color variable

• sweet, fruity, or perfume smell

• shape variable

• reward is nectar or pollen

• day-active

fly pollination (myophily)

• meat colored

• hairs present

• carrion smell AKA rotting flesh

• flat, deep trap

• reward a false promise of food for larvae

• day-active

carrion fly pollination (sapromyophily)

• color variable

• sweet, fruity, perfume smell

• open bowl to moderate tube shaped

• nectar guide present

• reward is nectar, pollen or wax

• buzz pollination

• day-active

bee pollination (melittophily)

• white, pale yellow, green or purple

• sweet or musty smell

• smell strongest at night

• often large and sturdy

• reward is nectar

• often positioned away from foliage and spines

• landing platform can be present or absent

• night-active

bat pollination (phiropterophily)

• day or night pollinated

• flower color variable or dull

• sweet smell

• bowl-shaped to moderately tubular

• reward is nectar

• often close to ground

• night-active

non-flying mammal pollination

common on islands where pollinating birds have been extirpated

lizard pollination