angiosperms

inherited traits from gymnosperms

producing wood (from xylem) and seeds

Ginkgo biloba

tolerates heat, cold, and pollution well

flowers

foster seed production

fruits

favor seed dispersal

endosperm

food helps embryo in seeds grow into seedlings

inflorescence

groups of flowers

carpels

bear female megasporangia

stamens

bear male miscrosporangia

perfect flowers

have both megasporangia and microsporangia

imperfect flowers

two flower types, male & female

• monoecious - male and female on same plant

• dioecious - male and female on different plants

coevolution

• fused petals - forms tubes to grant access

• timing of flowering targets specific targets

fruits

develop from ovaries after fertilization

• spread by animals excreting seeds

secondary metabolites

organic compounds that are not essential for cell structure but aids in survival and reproduction

• terpenes and terpenoids

• phenolics

• alkaloids

terpenes and terpenoids

citronella, rubber, turpentine, amber

phenolics

responsible for colors and flavors

• can be antioxidants

• some absorb UV radiation

alkaloids

affects animal nervous system

• caffeine, nicotine, morphine, etc

vegetative growth

• continuous

• growth of non reproductive parts of plant body (shoot/root)

reproductive development

produce short lived reproductive structures (flowers, seeds, fruits)

life spans

• annuals - plants that die after 1st year producing

• biennials - dont reproduce 1st year but 2nd

• perennials - produce each year

trichomes

leaf hairs, protection from solar radiation/herbivores

totipotency

plant cells can differentiate into any kind of cell

• due to stem cells in meristems

• repair damage

receptor molecules

sense stimuli and cause responses

phototropism

growing towards light source

hormones

• auxins

• cytokinins

• gibberellins

• ethylene

• abscisic acid

• brassinosteroids

gravitropism

+: downward growth of roots (with gravity)

(-): upward growth of shoots (against gravity)

auxins

promotes

• stem elongation

• fruit development

inhibits

• axillary bud outgrowth

• root elongation

• leaf fall

phototropism

gravitropism

cytokinins

stimulates cell division and vascular tissue growth

gibberellins

• stem elongation

• fruit growth

• flowering

• seed germination

ethylene

• influences cell expansion

• promotes leaf fall

• ripens fruit

abscisic acid (ABA)

stops plant growth when growing conditions are poor

• seed dormancy

brassinosteroids

• higher water intake

• foster cell expansion

photoperiod (day length)

flowering only occurs when days reach a specific length

• short day plant: night is longer

• long day plants: night is shorter

photoperiodism

depends on presence of photoreceptors

• phytochrome: red & far red recepter that influences seed germination/flowering

• Pr (inactive): inhibits germination

• Pfr (active): promotes germination