ch 10- plants Flashcards
what are the parts of the seed
seed coat
endosperm
embryo
what is the endosperm
storage material that provides the embryo with nutrients
what is the seed embryo
composed of radicle
hypocotyl
plumule
epicotyl
radicle
first to emerge
develops into root and anchors plant to soil
hypocotyl
bottom region of young shoot
plumule
develops into leaves
epicotyl
top region
shoot tip
germination
sprouting of seedling from previously dormant state in favourable condition
what is the most important condition for germination
water
imbibition
when the seed absorbs water which breaks the seed coat and initiates growth
where does plant growth take place
at the meristemsp
primary meristems
vertical growth at the apical meristems (tips of roots and shoots)
root zones
zone of division
zone of elongation
zone of maturation
secondary growth
horizontal growth occuring at lateral meristems - vascular cambium and cork cambium
only occurs in woody plants
vascular cambium
ring of meristematic tissue between primary zylem (more center) and primary phloem
cells produced inside this ring become secondary xylem (wood and pith) and cells on the outside of the ring become secondary phloem (bark and cork cambium)
secondary xylem and phloem
secondary zylem is produced each year producing rings but new phloem replaces old phloem
cork cambium
ring of meristematic tissue located outside the phloem and produces cork
groung tissue
parenchyma
collenchyma
sclerenchyma
parenchyma
filler tissue
makes up bulk of plant
thin cell walls
collenchyma
extra support in areas of active growth
irregular cell walls
sclerenchyma
main structural support
thick cell walls
stele
vascular tissue formed from xylem, phloem, and pith in centre of plant for transport
what is the pith made from
parenchyma
phloem
sugar transport from leaves to roots
made of
-sieve cells (long and lack organelles)-connected to form tunnel
-companion cells (connected to sieve cells, contain organelles for metabolic function)
xylem
transport water from roots to leaves
structural support
made up of
-tracheids (long and thin for water to travel through pits in tapered ends)
-vessel elements (short and stout- water travels via perforations in cell walls
dermal tissue
outer layer of plants that provides protection and regulation
-epidermis - cuticle covers it
-root hairs - inc surface area for greater nutrient and water uptake
casparian strip
made of fat and wax
impenetrable substance in cell walls of roots that forces water into cytoplasm for filtering before entering rest of plant
what causes stomata to open
water influx into guard cells makes them turgid
where are mesophyll cells located
between upper and lower epidermis
bundle sheath cells
surround and protect vascular bundles
cohesion tension theory
Transpiration, the
driving force, causes water to evaporate from the
stomata and leads to a transpirational pull. This
cohesive force (between similar substances, e.g.,
the water molecules) pulls the water column
upward.
capillary action
An adhesive force (between
dissimilar substances) due to attraction between
water and xylem vessels that causes water to
climb upwards.
root pressure
Builds up in roots to produce an
osmotic gradient, which drives water from soil
into the roots.
pressure flow hypothesis
Source cells produce
sugar and load it into phloem → increased sugar
concentration creates a gradient that pulls water into
phloem → turgor pressure in phloem increases,
resulting in bulk flow movement of sugar from leaves
down to roots.
what are the plant hormones
ethylene
auxins
cytokinins
gibberellins
abscisic acid
ethylene
gas that increases fruit ripening
auxins
cuases cell growth
work with cytokinins
responsible for plant tropisms
tropisms
plant growth in one direction
phototropism - growth towards light
gravitropism- growth away from pull of gravity
thigmotropism - growth in response to contact- vine growing up a wall
cytokinins
regulate cell differentiation and division with auxins
can prevent aging
gibberellins
stem and shoot elongation
elimination of domancy of seed
flowering
fruit production
leaf and fruit death
abscisic acid
functions during stress and promotes dormancy of seeds
closes stomata during droughts and inhibits growth
bryophytes
non vascular
seedless- no flower or fruit
low growing- horizontal spread
rhizoids, not roots
majority of life cycle in gametophyte stage
-reduced sporophyte that depends on and is attached to gametophyte
tracheophytes
vascular
seed brearing OR seedless
grow vertically and horizontally
root systems for anchorage
most of life cycle in sporophyte
diploid zygote becomes
sporophye via mitosis
in thier sporangia
sporophytes undergo MEIOSIS to produce haploid spores
spores become
gametophye via mitosis which produces gametes (still haploid) but those fuse to make the zygote
homosporous plants vs heterosporous plants
homosporous- bisexual gametophytes produces only one type of spore
heterosporous- produces two types of spores- megaspores develope into female gametophyte and microscopes develope into male gametophyte
what are examples of bryophytes
mosses
hornworts
liverworts
rhizoids
hair like projections that aid in water absorption and minor anchorage
seedless tracheophytes
lycophytes and pterophytes-
club moss
quillworts
fern
horsetail
mostly heterosporous with flagellated sperm
-independent gametophye and sporophyte life cycles
seed bearing tracheophytes
gymnosperm
-naked seeds
-conifers- fir, spruce, pine, redwood
-nonflagellated sperm dispersed by seed in wind
angiosperm
-most abundant
-flower bearing
-fruit producing
-nonflagellated sperm dispersed by wind or animals or pollen
-double fertilization
double fertilization
female gamete fertilized by two sperm
stamen
male sex organ composed of anther (site of microscope formation) and filament (supports anther)
microspore
produced in the anther in the stamen
it undergoes mitosis to form generative cell that contains sperm. and tube cells
pollen
made from the generative cell that contains sperm and the tube cell
both made from a microspore undergoing mitosis
pistil
female plant sex organ
made of
stigma- top of pistil - site of where pollen lands for germination
style - tube that leads to ovary
ovary - stores egg/ ovule
process of fertilization in plants
Pollen lands on stigma → tube cell elongates down
style forming pollen tube → generative cell travels
down pollen tube to ovary → splits forming two sperm
cells (double fertilization)
● One sperm cell meets ovule to form the seed or
embryo. Ovary develops into fruit, which is eaten
by animals and deposited in a new location (gene
migration).
● The other sperm cell combines with ovule’s polar
nuclei to form the endosperm.
megagametophyte
(female gametophyte) is
known as the embryo sac and develops within the ovule.
cotyledon
First leaves to appear on seedlings.
Contain nutrients from seed to feed the growing seedling.
monocots
single cotolydon
long narrow leaf
parallel veins
scattered vascular bundles
floral parts in multiples of 3
fibrous fine root system near surface
dicots
two cotolydons
broad leaf
network of veins
vascular bundles in ring
floral parts in 4 or 5
single taproot with branching
plants and nitrogen fixing bact
Plants have a symbiotic relationship with
nitrogen-fixing bacteria. Bacteria fix atmospheric
nitrogen into a usable form for plants; in return,
plants produce food for bacteria via photosynthesis.
nitrogen fixing bact- where are they found
in root nodules of legumes
nitrogen fixing bact
fix atmospheric nitrogen (N2) to ammonia (NH3) and ammonium (NH4+).
nitrifying bact
convert ammonia and
ammonium to nitrites (NO2-) and then to nitrates (NO3-).
nitrates
are taken up by plants (assimilation of
nitrogen) and incorporated into amino acids and
chlorophyll. Animals (consumers) acquire nitrogen
by eating plants (producers).
detritus
of dead decaying plants and animals
provides soil with nitrates.
denitrifying bact
convert nitrates back to
atmospheric nitrogen.
