Plant reproductive modes
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Plant reproductive modes. Dominant stage of life cycle:. Moss: gametophyte (sporophyte dependent). Comparison of reproductive modes of plants:. Fern: Sporophyte (gametophyte independent). Seed plants: Sporophyte (gametophyte reduced). Reliance on water for reproduction.

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Plant reproductive modes

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Plant reproductive modes

Plant reproductive modes

  • Dominant stage of life cycle:

  • Moss: gametophyte (sporophyte dependent)

  • Comparison of reproductive modes of plants:

  • Fern: Sporophyte (gametophyte independent)

  • Seed plants: Sporophyte (gametophyte reduced)

  • Reliance on water for reproduction

  • Moss: sperm swims in water to egg in archegonium

  • Fern: sperm swims in water to egg in archegonium

  • Seed plants: none; pollen transport sperm to egg

  • Protection of embryo

  • Moss: ‘embryo’ slightly protected in archegonia

  • Fern: embryo slightly protected in archegonium

  • Seed plants: ‘embryo’ well protected in seed coat

How are new organisms produced?


Plant reproductive modes1

Plant reproductive modes

  • Trends in floral specialization

  • Primitive flowers have many parts spirally arranged in whorls; radial symmetry (e.g. water lily)

  • Flowers

How are new organisms produced?


Plant reproductive modes2

Plant reproductive modes

  • Trends in floral specialization

  • Separate flower parts become fused (often into a tube)

  • Flowers

  • Whorls are ‘lost’

  • Flowers show bilateral symmetry

How are new organisms produced?


Plant reproductive modes3

Plant reproductive modes

  • Terminology

  • Perfectflower = contains both androecium (male) and gynoecium (female) whorls

  • Flowers

  • Imperfectflowers = missing one of ‘sex’ whorls

  • Staminate flower = male flowers (lack gynoecium whorl)

  • Pistillate flower = female flowers (lacs androecium whorl)

How are new organisms produced?


Plant reproductive modes4

Plant reproductive modes

  • Terminology

  • Imperfect flowers can occur on the same plant (e.g. birch) or on different plants (e.g. aspen)

  • Flowers

  • Monoecious = separate staminate and pistillate flowers on the same plant

  • Dioecious = staminate and pistillate flowers on separate plants

How are new organisms produced?


Plant reproductive modes5

Plant reproductive modes

  • Pollination

  • Pollination = process by which pollen is placed on stigma

  • Flowers

  • Early seed plants pollinated by wind (like pines)

  • Earliest flowering plants pollinated by insects; both flowering plants and insects diversified about same time (100 mybp)

  • Most numerous groups of flowering plants pollinated by bees

  • Bees locate flowers by odor and flower color

  • Bee-pollinated flowers tend to be blue or yellow

  • Many flowers have UV lines or bull’s eyes to indicate the location of nectaries

How are new organisms produced?


Plant reproductive modes6

Plant reproductive modes

  • Some bees (and wasps) not given nectar or pollen ‘reward’

  • Flowers

How are new organisms produced?


Plant reproductive modes7

Plant reproductive modes

  • Other common pollinators

  • Butterflies:

  • Flowers

  • Flowers have long, slender floral tubes

  • Flowers have ‘landing platform’

How are new organisms produced?


Plant reproductive modes8

Plant reproductive modes

  • Other common pollinators

  • Moths:

  • Flowers

  • Flowers have long, slender floral tubes

  • Flowers have ‘landing platform’

  • White or yellow and heavily scented

How are new organisms produced?


Plant reproductive modes9

Plant reproductive modes

  • Other common pollinators

  • Hummingbird:

  • Flowers

  • Flowers have long, slender floral tubes

  • Large amounts of nectar

  • Red color (conspicuous to birds but not insects)

How are new organisms produced?


Plant reproductive modes10

Plant reproductive modes

  • Other common pollinators

  • Bats:

  • Flowers

  • Flowers white, heavily scented

  • Large amounts of nectar

How are new organisms produced?


Plant reproductive modes11

Plant reproductive modes

  • Wind pollination

  • Flowers usually small, green, odorless

  • Flowers

  • Often grouped together in hanging catkins

  • Flowers emerge before leaves

  • Common in grasses

How are new organisms produced?


Plant reproductive modes12

Plant reproductive modes

  • pollination

  • Outcrossing = movement of pollen between different flowers

  • Flowers

  • Outcrossing prevent inbreeding in plants

  • Factors that promote outcrossing:

  • Have separate male and female plants (dioecious plants)

  • Monoecious plants mature staminate and pistillate flowers at different times

  • Plants with perfect flowers mature stamen and pistils at different times (= dichogamous)

How are new organisms produced?


Plant reproductive modes13

Plant reproductive modes

  • Factors that promote outcrossing:

  • Flowers

  • Genetic self-incompatibility

  • Gametophytic: if either allele of stigma matches allele of pollen that pollen’s tube is blocked

  • Sporophytic: if any allele of pollen matches an allele of stigma no pollen tubes are produced

How are new organisms produced?


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