Ch. 7: Plant Growth and Reproduction

Terms Biotic pollination: pollen carried animal--90% flowering plants

Terms Biotic pollination: pollen carried by animal--90% flowering plants Floral visitor: visits Pollinator: deposits

Pollination as Mutualism Mutualism (+,+) interaction Plant gets pollen transferred Animal gets “reward” Reward?

Animal Rewards Pollen: high protein Also has lipids, minerals, starch Renewable…

Rewards Pollen renewed by: sequential anther dehiscence (multiple stamens) Tony Danza’s Masters Study Creosote bush

Rewards poricidal anthers (buzz pollination): anthers have Vaccinium (blueberry)

Rewards Nectar: (nectar glands: nectaries) Who am I?

Rewards Nectar: 10-60% sugars Amino acids (butterfly flowers) Renewable!

Rewards Oils/Resins: Krameria wax gland: wasp food! nest construction materials “cologne” (male bee uses oil: ) larval food (Krameria) Krameria wax gland: wasp food!

Pollination Benefits animal pollination 1) Directed dispersal pollen: Gene flow! Record distance? Tropical orchid

Pollination Benefits animal pollination Directed dispersal: aided by learning ( “handling time”) Fosters “floral constancy” (visit 1 sp ) Bumblebee visits to touch-me-not

Pollination Benefits animal pollination stigma style ovary 2 ovules 2) Style as “selective racetrack” 1 pollen grain fertilize 1 ovule Suppose 5 pollen grains arrive How many fertilize an ovule? Pollen grains stigma style ovary 2 ovules

Pollination Benefits animal pollination stigma style ovary 2 ovules 2) Style as “selective racetrack” Pollen tubes 1N If allele recessive, then Pollen grains stigma style ovary 2 ovules

Pollination Benefits of animal pollination stigma style ovary 2 ovules 2) Style as “selective racetrack” Fittest (fastest) pollen grains Pollen grains stigma style ovary 2 ovules

Pollination Style as “selective racetrack” Ex., Coyote melon Gourd in U.S. deserts.

Pollination Style as “selective racetrack” Study (2000) showed: 1) 900 grains: fully pollinate 2) 1 visit 650 grains/flower. By 2 hr, >4000 deposited 3) Over-pollinated: more vigorous seedlings

Outcrossing Major benefit sexual reproduction: generate genetic variation by mating w/ others (outcrossing) Why just enhanced?

Outcrossing Why just enhanced? Making gametes by meiosis: 23 pairs of chromosomes gives 8 million different combinations of Mom’s and Dad’s chromosomes in gametes

Outcrossing Favor outcrossing: 1) Dioecy

Outcrossing Favor outcrossing: 2) Floral morphology Heterostyly: Diff. stamen/style lengths Distyly: 2 diff. “morphs” perfect flowers

Outcrossing Ex, Gelsemium sempervirens

Outcrossing Favor outcrossing: 3) Floral phenology Protandry: anthers Protogyny: stigma Protandry

Outcrossing Favor outcrossing: 4) Self-incompatibility: stop

Pollination syndromes Pollination Syndrome: flower traits & pollinator traits that adapt each to other Disclaimer: We make broad generalizations and exceptions exist to most statements!

Pollination syndromes Bee pollination Bees: intelligent, agile Good sight ( good smellers European honeybee Halictid bee Leafcutter bee Bumble bee

Pollination syndromes Flowers: Colorful (not red) Landing platform: place Mildly fragrant Often nectar guides: patterns Orchid flower with nectar guides (lines) on petals Petals in visible light (top) and UV (bottom)

Pollination syndromes Fremontodendron decumbens (endangered chaparral shrub) flowers UV reflectance photo (right) Tony Danza??

Pollination syndromes Beetle pollination Beetles: Clumsy, dumb Poor vision, good smellers

Pollination syndromes Beetle pollination Beetles: Clumsy, dumb Poor vision, good smellers Flowers: Lg (or lg inflorescences) Lite color Smelly

Pollination syndromes Bird pollination: Flower-visiting birds: Agile, long beak visual: see red poor “smell” Hummingbirds (native to Americas) hover

Pollination syndromes Flowers: red/orange Nectar (tube) little No ??? Aloe

Pollination syndromes Butterfly pollination Butterflies: good vision/smell, long tongue Don’t hover well coiled tongue tongue extended

Pollination syndromes Flowers: Color varies (blue, yellow, orange) Landing Nectar Phlox pilosa

Pollination syndromes Bat pollination Nocturnal: sight good (but it’s dark!) Good Agile

Pollination syndromes Flowers Open night: light color Lots Fragrant May be pendant Parkia flowers

Pollination syndromes Bat pollination: Mainly tropical In U.S., saguaro Saguaro cactus Saguaro flowers