Plants Flashcards
Thallophytes
Simplest form of a plant with no specialized vascular system
Aquatic environments
Bryophytes
Aquatic and lan habitats
Dominant gametophyte stage (haploid)
Bryophytes examples
Mosses, liverworts, hornworts
Tracheophytes
Grow vertically and tall
Dominant sporophyte (diplod)
Tracheophyte examples
Ferns, Pine trees
Angiosperms
Undergo double fertilization
diverse land based plant
non flagellated male gametes
produce flowers and have pollen
bear seeds in fruits
Monocots
One cotyledon
parallel veins
scattered vascular bundles
fibrrous root system
flower parts in multiples of 3
Monocots examples
Lilies and kentucky bluegrass
Dicots
Two cotyledons
Net like veins
ringed vascular bundles
large sinle tap roots
flower parts in multiples of 4 or 5
Dicot examples
Oak trees
Angiosperm lifecycle
- Meiosis in ovary: megasporocyte, the megaspore mother cells (2n) are converted into four megaspores (n) via meiosis
- Mitotic divisions: one megaspore survives and undergoes mitosis once fertilized to produce the egg cell and polar nuclei
- Meiosis w/in anther: microsporocytes to four microspores via meiosis
- Mitoti divisions male: microspore undergoes mitosis producing male gametophyte or the pollen grain. Male gametophyte contains generative cell and tube cell
- Pollen tube: upon reaching ovule, two sperm are discharged
- Double fertilization: Only male gamete fuses with the female egg gamete to form an embryo and another male gamete fuses with polar nuclei to form endosperm
- Zygote develops into embryo
Plant tissue
Dermal tissue
Epidermal cells covering outside of plant parts, secrete waxy protectice substane in aerial portions of plant
Contain guard cells to help control gas exchange
Ground tissue
Responsible for most of the metabolic functions
Xylem
Conducts water and minerlas throughout plant
provide mechanical support
Xylem cells
Tracheids: long and tapered, water passes laterally from one to another through pits
Vessel elements: short and wide, have little to no taper at ends, perforations allow for water to pass from one vessel to another
Phloem
Transports sugar throughout plant
made of cells: sieve tube members
angiosperm seed structure
Seed coat
tough outer covering of seed that protects embryo/seed content
Storage material
Endosperm: primary storage tissue
Cotyledons: trasnfers nutrients from endosperm to embryo
Embryo
Diploid
developed from fertilized egg
Tropism type
Phototropism
Bending of a plant in response to light
gravitropism
bending of a plant in response to gravity
thigmotropism
growth response to mechanical stimuli
plant hormones
Auxin
influences plants response to light + gravity yo stimulate growth
Gibberellins
Promote flower + stem elongation
Cytokinins
stimulate cytokinesis
abscisic acid
inhibits growth and promotes seed dormancy
ethylene gas
promotes fruit ripening, flower production, leaf abscission
Leaf structure
Leaf structure
Epidermis, Palisade mesophyll, vascular bundles, guard cells, spongy mesophyll, stomata
Epidermis
Protective layer covered w/ cuticle to reduce transpiration
Palisade mesophyll
has cells w/ chloroplasts and is the primary site for leaf photosynthesis
Vascular bundles
consist of xylem and phloem; surrounded by bundle sheath cell
guard cells
specialized epidermal cells to control opening of stomata and permit gas exchange
Spongy mesophyll
Intracellular spaces allow for gas travel
Stomata
pore in epidermis that allows for gas exchange between plant and external environment
Open CO2 can enter the leaf where photosynthesis can make sugar
Closed water loss is minimized but CO2 cannot enter the cells of the plant which prevent calvin cycle from taking place
Growth type
Growth type
primary, secondary, photoperiodism, short day plants, long day plants
Primary
Increases length of plant
Secondary
Increases girth of plant
Photoperiodism
Plant’s response to changes in length day and night
Short day plants
Flower when sunlight is less that half the day
Long day plants
Flower when sunlight is more than half the day
