Ch. 7: Plant Growth and Reproduction. Terms Biotic pollination: pollen carried animal--90% flowering...
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Transcript of Ch. 7: Plant Growth and Reproduction. Terms Biotic pollination: pollen carried animal--90% flowering...
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 MutualismMutualism (+,+) 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:
– 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
– 2) Style as “selective racetrack”– 1 pollen grain fertilize 1 ovule– Suppose 5 pollen grains arrive– How many fertilize an ovule? stigma
style
ovary
2 ovules
Pollen grains
Pollination• Benefits animal pollination
– 2) Style as “selective racetrack”– Pollen tubes 1N– If allele recessive, then
stigma
style
ovary
2 ovules
Pollen grains
Pollination• Benefits of animal pollination
– 2) Style as “selective racetrack”– Fittest (fastest) pollen grains
stigma
style
ovary
2 ovules
Pollen grains
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 chromosomesgives 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
•Disclaimer: We make broad generalizations and exceptions exist to most statements!
• Pollination Syndrome: flower traits & pollinator traits that adapt each to other
Pollination syndromes• Bee pollination• Bees:
– intelligent, agile– Good sight (– good smellers
Leafcutter bee Bumble bee
Halictid bee
European honeybee
Pollination syndromes• Flowers:
– Colorful (not red)– Landing platform: place – Mildly fragrant– Often nectar guides: patterns
Petals in visible light(top) and UV (bottom)
Orchid flowerwith nectarguides (lines)on petals
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 tonguetongue extended
Pollination syndromes• Flowers:
– Color varies (blue, yellow, orange)– Landing – Nectar
Phloxpilosa
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 flowers
Saguaro cactus