organismal bio Flashcards
eukaryote
cells with linear chromosomal DNA packed into a membrane enclosed nucleus
contain membrane enclosed organeless (mitochondia and/or plastids)
prokaryotes
cells that have no nucleus and no membrane-enclosed organelles
DNA contained in a circular chromosome (plasmids)
anaerobe
metabolism without oxygen
aerobe
metabolism with oxygen
phototroph
organisms that get energy from light—not all photoautotrophs do oxygenic photosynthesis
chemotroph
energy that comes directly from chemical rxns
autotroph
organism that generates their own food from inorganic molecules
heterotroph
consumes food produced by other organisms
plasmid
small, circular, double stranded DNA molecule that carries accessory genes separate from those of a bacterial chromosome
binary fission
cell that doubles in cell that then splits into 2 cells
method of asexual reproduction
NO MITOSIS in prokaryotes
stromatolite
layers of rock that results from the activities of prokaryotes that bind thin films of sediment(ed) minerals together
plastid
family of closely related organelles including chloroplasts; found in photosynthetic eukaryotes
cyanobacteria
1st photoautotrophs that capture light energy thru oxygenic photosynthesis
endosymbiosis
a relationship between two species in which one organism lives inside the cell or cells of another organism
ex: mitochondria and plastids
microbiome
refers to all microorganisms found in a given well-defined habitat
the collection of microorganisms living in or on an organism’s body along with their genetic material
horizontal transmission
acquired from the environment
vertical transmission
passed down directly from parent to offspring
ex: germline transmission of intracellular symbionts; acquisition during passage thru the birth canal
heterocyst
a specialized cell that engages in nitrogen fixation in some filamentous cyanobacteria
metabolite cross-feeding
interactions between bacterial strains in which molecules resulting from the metabolism of one strain are further metabolized by another strain
filamentous chain
in some cyanobacteria like Anabaena, some cells in chain will differentiate and become heterocysts
allows spatial separation of nitrogen fixation (anaerobic) from photosynthesis (aerobic)
biofilm
a surface coating colony of one or more species of microbes that engage in metabolic cooperation
mats of cells that secrete and become stuck to each other in a matrix of polysaccharides and proteins
- adheres to surface because cells are secreting sticky substances/sugars/proteins
quorum sensing
if enough other microbes of the same type nearby —> a new density dependent activity is induced
cells know when the population reaches high density thru the conc of secreted autoinducer molecules
ex: bobtail squid
autoinducer
pheromone that lets cells know when the population reaches a high enough density
absorptive nutrition
fungi secrete enzymes to digest its food externally
hyphae
a single filament; one of many connected filaments
mycelium
network of hyphae
indeterminate growth
growth that occurs in fungi with no end structure
mycelium networks contribute to this bc the tips for hyphae keep extending
arbuscular mycorrhizal fungi
penetrates root cells and create arbuscules
- hyphae interact with roots and penetrate them; go into the cell thru the cell wall of root cells to form arbuscules and form networks inside
ectomycorrhizal fungi
form nets around the while root and cell surfaces within root but do not enter cells
spores
single cells capable of growing into an adult organism
a haploid cell in FUNGI produced (a)sexually that produces a mycelium after germination
meiosis
production of haploid cells from a diploid cell over 2 rounds of cell division
fertilization
union of haploid gametes produce a diploid zygote
sporogenesis
process of spore production
gametogenesis
process of gamete production
sporophyte
diploid organisms that produces spores by meiosis
gametophyte
haploid organisms that produces gametes by mitosis
fruiting body
contains spores
basidium
a reproductive appendage that produces sexual spores on the gills of mushrooms (club fungi/basidimycetes)
basidiocarp
elaborate fruiting body of a fungi
plasmogamy
fusion of the cytoplasm of cells from 2 individuals
occurs of stage 1 of fertilization of sexual reproduction of fungi
nuclei don’t fuse
heterokaryon
the nuclei during plasmogamy don’t fuse (n+n)
karyogamy
different haploid nuclei sharing the same cytoplasm then fuse to make the diploid zygote
mycosis
fungal infection
monophyletic group
clade/subset of the tree of life that contains all of the descendants emerging from a single common ancestor
ecological group
set of taxa that share common ways of life, often in a community context
primary endosymbiosis
1st case where something that is not photosynthetic establishes an endosymbiosis with something that is
eukaryotic cell engulfs a prokaryotic cell (e.g. cyanobacterium or other photosynthetic prokaryotes) and develops an endosymbiotic relationship with it
secondary endosymbiosis
rather than establishing a new endosymbiosis with a cyanobacteria, instead it establishes an endosymbiosis with a eukaryotic algal (red or green) species
haplodiplontic life cycle
alternating between diploid and haploid phases on a lifecycle cycle
both phases can involve mitosis
multicellular organisms in BOTH phases
diatom
unique glass like cell walls made of silica embedded in a matrix
diatom deposits accumulate on the ocean floor
- when tectonic plates move and fossilize them = creates diatomaceous earth
dinoflagellates
algae with 2 flagella, one in which is a spiral that can make them spin
dinos - whirl
phycocolloid
polysaccharide compounds produced by cells walls that prevent dying out/desiccation
lichen
an ecological group consisting of a mycobiont (heterotrophic fungus) and a photobiont (photosynthetic algae or cyanobacteria)
soredia
bundles of fungi and algae
in lichens, a small cluster of fungal hyphae with embedded algae
seed-free plant
plant does not a protected embryo
bryophytes
moss, liverworts, hornworts
no vascular system or seed
non vascular plant that lives on land but lacks some of the terrestrial adaptations of vascular plants
desiccation
drying out; removal of moisture
phyllids
thin leaf-like growths/tissues that absorb water through direct contact with ground or trapped moisture
where water is mostly absorbed by a bryophyte/moss
collect water from the air that’s there as humidity, fog, dew
NOT LEAVES -> LEAFS DUPE
rhizoids
long tubular single cell or filaments that do some water/nutrient uptake but mainly function to anchor plant
NOT ROOTS -> ROOTS DUPE
also associate with arbuscular mycorrhizal fungi
gametangia
new multicellular protective tissues where gametes form
multicellular plant structure in which gametes are formed
antheridia
gametangia that produces sperm
archegonia
gametangia that produce eggs
embryo
the zygote (fertilized egg) is also retained in the archegonium and develops embedded in and DEPENDENT on nutrition from maternal tissue
cuticle
waxy waterproof for sporophyte generation
provide protection
keep moisture inside their cells
sporangia
container
a multicellular organ in fungi and plants in which meiosis occurs and haploid cells develop
sporopollenin
a polymer that prevents desiccation of charophyte zygotes; make plant spores resistant to harsh environments and capable of dispersal by air
sporophyll
modified leaf that bears sporangia and hence is specialized for reproduction
sorus (pl. sori)
clustered groups of sporangia on vascular plants
on fern sporophyll
peat
partly decayed organic material found in huge, boggy (swamps) wetlands
extensive deposits of partially decayed organic material often formed primarily from wetland moss
lycophytes
club mosses, spike mosses, quillworts
leaves and roots evolved independently
leaves are microphylls with a single unbranched veins (branching only occurs at shoot tip)
monilophyte
ferns, horsetails, whisk ferns
leaves are megaphylls with branched veins thru leaves
potential for stem branching no limited to shoot tip
microphyll
a small, usually spine shaped leaf supported by a single strand of vascular tissue
only found in lycophytes
megaphyll
a leaf with a highly branched vascular system found in almost all vascular plants other than lycophytes
carboniferous period
period marked by giant plants, and by the great expansion of carbon dioxide sinks as massive amounts of carbon were sequestered as minerals
azolla
fairy moss, mosquito form, water fern
an aquatic fern that forms a symbiotic association with nitrogen fixing cyanobacteria that it makes a home for within pouches in its leaves
dead azolla accumulated as stagnant sediment, drawing co2 out of the atmosphere and sinking it to the ocean floor
caused cooling
azolla event:icehouse earth age with ice caps
heterospory
a plant species that has two kinds of spores
gymnosperm
naked seed
vascular plant that bears naked seeds — seeds not enclosed in protective chambers
seed
an adaptation of some terrestrial plants consisting of am embryo packaged along with a store of food within a protective coat
scales
modified leaves with sporangia
cones
they are sporophyll and part of the 2n sporophyte
cones
gymnosperm reproductive structures
anatomically akin to compressed fern fronts or lycophytes strobili
megasporangium
make megaspores that germinate to become the female gametophyte
megaspore
a spore from a heterosporous plant that develops into a female gametophyte
microsporangia
make microspores that germinate to become the male gametophyte (pollen)
microspore
a spore from a heterosporous plant species that develops into the male gametophyte
ovule
megasporangium surrounded by the protective structure that will become the seed coat
pollen grain
in seed plants, a structure consisting of the male gametophyte enclosed within a pollen wall
pollen tube
a tube that forms after germination of the pollen grain and that functions in the delivery of sperm to the ovule
pollination
the transfer of pollen to the part of a seed plant containing the ovules, a process that required for fertilization
seed coat
a tough outer covering of a seed formed from the outer coat of an ovule
flowering plants = seed coat enclosed and protects the embryo and endosperm
integument
layer of sporophyte tissue that contributes to the structure of an ovule of a seed plant
icehouse / greenhouse earth
lower co2 levels causing a big drop in global temperature that caused a long extended period with polar ice caps
angiosperm
container seed
a flowering plant which forms seeds inside a protective chamber (ovary)
determinate growth
growth in which growth stops after a certain size in reached
plant develops with a fixed endpoint
whorls
how flower parts are arranged on that axis in a sequential order
sepal
offer protection to the bud
a modified leaf in angiosperms that helps enclose and protect a flower bud before it opens
petals
often bright, large and attractive to pollinators
a modified leaf of a flowering plant
stamen
fertile organs that bear POLLEN
pollen producing reproductive organs of a flower, consisting of an anther and filament
filament
stalk part of the stamen that bears the anthers
anther
sac that contains the microsporangia where microspores form and germinate to become pollen (gametophyte)
the terminal pollen sac of a steam where pollen grains containing sperm producing male gametophytes form
carpel
sporophyll fused into a container within which the ovules are found
ovule producing reproductive organ of a flower (stigma, style, ovary)
flower
in flowers: specialized shoot with up to 4 sets of modified leaves, bearing structures that function in sexual reproduction
pistil
single carpel or collection of fused carpels
stigma
sticky surface where pollen land and pollen tube germinates; receives the pollen grain
style
tract down which the pollen tube migrates to reach ovules
this stalk of a flower with the ovary at the base and the stigma at the top
ovary
protective container around ovules
portion of the carpel in which the egg containing ovules develop
inflorescence
the flowering stalk
a group of flowers tightly clustered together
inbreeding depression
deleterious recessive mutations are exposed in offspring, lowering fitness
nectar guide
markings that attract and orient pollinators
coevolution
joint evolution of two interacting species in response to selection imposed by the other
pollination syndromes
suites of plant traits that suggests coevolution with a particular group
buzz pollination
vibration can get pollen out
ex: bumblebees vibrating their wings
central cell
2 nuclei in a cell
double fertilization
a mechanism of fertilization in angiosperm in which two sperm cells unite with 2 cells in the female gametophyte (embryo sac) to form the zygote and endosperm
endosperm
result from double fertilization; triploid cell (3n)
a nutrient rich tissue formed by the union of a sperm with two polar nuclei during double fertilization; provides nourishment to the developing embryo in angiosperm seeds
monocot
has one cotyledon
endosperm is a liquid in these seeds (like coconuts and corn) with loose nuclei floating around that eventually cellularized into a starchy solid that provides nutrition to the embryo
eudicot
have two cotyledons (embryonic leaves)
endosperm starches are taken up by the growing embryo as the seed develops and is stored in the cotyledons
cotyledons
embryonic leaves
a seed leaf of an angiosperm embryo
pericarp
ovary wall becomes the thickened call of the fruit
growth
increase in size of a tissue
cell division
increasing cell number
cell elongation
increasing a cell size
determination
commitment of a cell to a particular fate
differentiation
the process of expressing the characteristics of a particular cell fate or tissue identity
shoot system
the aerial portion of a plant body consisting of stems, leaves, and flowers
shoot apical metistem
the tip of the shoot is the primary site of cell division for the shoot
root apical meristem
the tip of the root that is the primary site of cell division for the roots
apical meristem
a localized region at a growing tip of a plant body where one or more cells divide repreatedly
dividing cells enable plant to grow in length
coleoptile
the covering of the young shoot of the embryo of a grass seed
epicotyl
embryonic shoot above the cotyledons (tipped by SAM)
embryonic axis above the point of attachment of the cotyledons and below he first pair of miniature leaves
hypocotyl
embryonic shoot below the cotyledons
the embryonic axis below the point of attachment of the cotyledons and above the radicle
radicle
embryonic root of a plant (tipped by RAM)
apical hook
hypocotyl emerges bent in a hook that protects the SAM as shoot grows to soil surface
node
a point along the stem of a plant at which leaves are attached
sites where structures extend from stems
internode
spans of stem between nodes
a segment of a plant stem between the points where leaves are attached
branches
stems that develop from auxiliary buds that grow from axils
axillary bud
a structure that has the potential to form a lateral shoot or branch
appears in the angle formed between a lead and a stem
axil
intersections where leaf meets stem
blade
flat part of the leaf that’s intercepting light to do photosynthesis and then send that sugar to the rest of the plant
petiole
stem-like structure supporting the blade; connects blade of leaf to stem
the stalk of a leaf which joints the lead to a node of the stem
dermal tissue
covers and protects the plant from external insults (pathogens, predators, etc.)
help plants retain moisture the plant has within
the protective coating of plants
ground tissue
anything not dermal or vascular; can serves as the sites of photosynthesis, provide the supporting matrix for the vascular tissue, and help store water and sugars
vascular tissue
transport water, minerals, and sugars throughout the plant
plant tissues consisting of cells joined into tubes that transport water and nutrients throughout the plant body
parenchyma
type of ground tissue
alive at maturity
simple cell walls (made of cellulose and not particularly thick)
can perform diverse functions (photosynthesis, starch storage, water movement, may divide and differentiate into other cell types)
a relatively unspecialized plant cell type that carries out most of the metabolism, synthesizes and stores organic products, and develops into a more differentiated cell type
collenchyma
type of ground tissue
alive at maturity
more thickened cell walls, especially at the corners —> allows them to create more connected structures and often run parallel to the stem surface
function and provide structural support
colla = glue
a flexible plant cell type that occurs in stranded or cylinders that support young parts of the plant without restricting growth
sclerenchyma
type of ground tissue
scleros = hard
have lignin embedded in very thick cell walls
function in support and protection
often dead but may be alive (lignin prevents things from entering and exiting —> nutrients, water, etc.
a rigid supportive plant cell type usually lacking a protoplasm and possessing thick secondary walls strengthened by lignin at maturity
sclereids
type of sclerenchyma
several cells found in a cluster
formation of a harder surface
small with thick walls
often found in fruit walls like nut shells or in seed coats
fiber
type of sclerenchyma
cells are elongated and found in bunches
function in structural support
epidermis
the layer of tightly packed cells that form the outermost tissue of all plants
protect the plant from all environmental insults
leaf and stem are epidermal cells coated in cuticle that helps prevent desiccation
guard cells
type of epidermal cell
two cells that flank the stomatal pore and regulate the opening and closing of the pore
pavement cell
type of epidermal cells
cells that are very tightly packed together that create an outer skin of the plant
trichomes
hairlike outgrowths on stems, leaves, or flowers that come in diverse forms
an epidermal cell that is a highly specialized, often hairlike outgrowth on a plant shoot
can be glandular (able to manufacture and secrete chemicals) or nonglandular
function in defense from herbivores, thermoregulation, reflection, reducing evaporation, reaction triggers
root hair
increase surface areas for water absorption and minerals
a tiny extension of a root epidermal cell, growing just behind the root tip and increasing SA for absorption of water and minerals
xylem
vascular plant tissue that conducts water and minerals UPWARD from the roots to the rest of the plant
consist mainly of tubular dead cells
tracheid
a long, tapered water-conducting cell found n the xylem of nearly all vascular plants
functioning tracheids are dead
relatively, NARROW, dead when functional with totally open interiors and lignified cell walls
no openings at end; water moves laterally by pits where tracheotomy cells are in contact with
vessel element
open, dead cells with lignified cell walls, but much wider
open end to end allowing formation of long vessels with free water movement
a short, wide, water-conducting cell found in the xylem of the most angiosperm and a few non-flowering vascular plants
dead at maturity
phloem
vascular plant tissue consisting of living cells that transport sugars and other organic nutrients to the rest of the plant
cells arranged into elongated tubes
sieve tube elements
connect end to end allowing formation of sieve tubes
a living cell that conducts sugars and other organic nutrients in the phloem of angiosperms
end are not totally open
sieve plates
end walls present but with many pores
an end wall in a sieve tube element which facilitates the flow of phloem sap in angiosperm sieve tubes
companion cell
paired, non-conducting cells are connected to sieve tube elements
a type of plant cell that is connected to a sieve tube element by many plasmodesmata and whose nucleus and ribosomes may serve one or more adjacent sieve tube elements
plasmodesmata
channels that pass sugars, nutrients, and large molecules necessary to keep sieve tube elements alive to them
an open channel thru the cell wall that connects the cytoplasm of adjacent plant cells, allowing water, small solutes, and some larger molecules to pass between the cells
taproot
the main vertical root that develops from an embryonic root and gives rise to lateral (branch) roots
lateral root
secondary branches
a root that arises from the pericycle of an established root
fibrous root
primary root die and instead a shallow network establishes with new roots that come off the stem and where no one branch predominates
root cap
terminal structure that first encounters obstacles
protects the RAM
secretes a slime that allows growth thru soil
site of gravity perception
a cone of cells at the top of a plant root that protects the apical meristem
zone of differentiation
area where cells takes on their distinct types (e.g. root hairs emerge)
region of root with the oldest root cells
zone of elongation
cells can grown up to 10x initial length, pushing tip down further into soil
zone of cell division
includes RAM and its immediate products of cell division
cortex
starch tissue storing parenchyma with intercellular spaces
ground tissue that is between the vascular tissue and dermal tissue in a root or eudicot stem
endodermis
one cell thick layer that creates a boundary with the vasculature
the innermost later of the cortex that surrounds the vascular cylinder
pericycle
outer vascular layer surrounding the xylem and phloem
lateral roots arise from meristematically active regions
macronutrients
an essential element that an organism must obtain in relatively large amounts
c, h, o = fixed as sugars by photosynthesis (h2o + co2)
p, k, n, s, ca, mg = come from soil (1-4% dry weight)
micronutrient
an essential element that an organism needs in very small amounts mostly as enzymatic co-factors
too much = bad
cl, cu, fe, mn, zn, mo, b, ni
symplast
all the cytosol contained within plasma membranes
the continuum of cytosol connected by plasmodesmata between cells
plasmodesmata pass thru plasma membranes and cell walls
apoplast
everything exterior to cell membranes
water, minerals, and other dissolved substances can move thru cell walls, intercellular spaces of cortex, and space between dead structures (xylem vessels, tracheids)
transmembrane route/plasma membrane
a filter —> selectively permeable
substances pass thru the routes while still in the cortex via the plasma membrane
plasma membrane
the membrane at the boundary of every cell that acts as a selective barrier, regulating the cell’s chemical composition
casparian strip
a layer of waxy and waterproof material (suberin) that blocks all passage
a water impermeable ring of wax in the endodermal cells of plants that blocks the passive flow of water and solutes into the stele by the way of cell walls
suberin
layer of waxy material on the casparian strip
phyllotaxy
the non-random order and arrangement of primordia initiation
simple leaf
has a single, undivided blade
compound leaf
the blade consists of multiple leaflets
leaflet has no axillary bud at its base
rhizomes
underground stems that can put up new shoots
stolons
“runners”
stems that extend along the soil surface and establish new plantlets with leafs and roots at nodes
persist even if cut or original plant dies
stem tubers
enlarged ends of rhizomes or stolons that store food
thorns
modified axillary branches
modified for defense
prickles
NOT MODIFIED AXILLARY BRANCHES
modified epidermal extensions of the stem
secondary growth
drives the thickening of plant stems
growth produced by lateral meristems, thickening the roots and shoots of woody plants
mostly occur in eudicots and conifers
involves new lateral meristems self-renewing tissues that form cylindrical bands (or circular band in cross sections) once that part of the stem has finished elongating/primary growth
primary growth
growth produced by apical meristems, lengthening / elongating stems and roots
vascular cambium
lateral meristematic tissue that runs between xylem and phloem
adds more of those tissues, widening the shoot while also increasing vascular flow and support
a cylinder of meristematic tissue in woody plants that adds layers of secondary vascular tissue (secondary xylem/ wood and secondary phloem)
cork cambium
lateral meristematic tissue that develops from parenchyma within the cortex
produces a tough, thick, waxy covering (cork) that protects stem from water loss and from invasions by pathogens and insects
a cylinder of meristematic tissue in woody plants that replaces the epidermis with thicker, tougher, cork cell
cork
tough, thick, waxy covering that protects stems from water loss and from invasions by pathogens and insects
secondary xylem
cells are formed in the INSIDE of the VC
become wood
secondary phloem
cells form to the OUTSIDE of the VC
become bark
annual rings
inner xylem tissue grows unevenly across seasons
sapwood
most recent several layers of secondary xylem which DO conduct water
heartwood
older layers of secondary xylem which NO LONGER conduct water
cohesion
linking of like molecules often by hydrogen bonding
surface tension
consequence of cohesion
measure of how much force is needed to break the water surface
evaporation
water becomes water vapor —> energy required to break h-bonds
transpiration
loss of water vapor from leaves
osmosis
PASSIVE diffusion of water down the concentration gradient across a membrane
diffusion of free water across a selectively permeable membrane
bulk flow
movement of fluid due to a difference in pressure between two locations
active transport
pumps ions across a membrane to create a concentration gradient
movement of a substance across a cell membrane against its concentration or electrochemical gradient, mediated by specific transport proteins and requiring an expenditure of energy
water potential (psi)
the physical property that predicts which direction water will move
governed by solute concentrations and applied pressure
turgid
swollen or distended
a walled cell becomes turgid if it has a lower water potential than its surroundings, resulting in the entry of water
when placed in an environment with high conc of free water, water will rush into the cell
turgor pressure
force directed against a plant cell wall after the influx of water and swelling of the cell due to osmosis
positive pressure potential
solute potential (psi, s)
component of water potential that is proportional to the molarity of a solution
measures the effect of solutes on the direction of water movement
either 0 or negative
always negative when solutes are present
pressure potential (psi, p)
a component of water potential that consists of the physical pressure on a solution, which can be positive, 0 or negative
mesophyll
middle + leaf
between top (bundle sheath cells) and bottom epidermis
palisade mesophyll
consists of elongated chloroplast rich cells specialized for light capture
spongy mesophyll
form a porous space with high SA:V ratio that allows for gas circulation
bundle sheath cells
surround veins and regulate transfer of substances between mesophyll and vasculature
phloem sap
the sugar rich solution carried thru a plant’s sieve tubes
phenotypic plasticity
phenotypic variation produced due to individuals of the same genotype experiencing different environments
capacity of an individual genotype to produce different phenotypes to change its traits depending on the environment experience
developmental plasticity
environment dependent changes in growth, developmental patterning, or developmental timing
often an environmental cue experienced by one tissue or life stage determines the developmental response by another tissue or life stage
perception
sensing and interpreting complex environmental cues
transduction
communication information (the cues) to nucleus OR to another tissue entirely
response
local changes to cells and tissues appropriate to the stimuli perceived
cue
stimulus from the environment (biotic or abiotic)
sensor
some type of protein, hormone, etc. that
a receptor of the cue that responds to the stimulus
hormone
mobile signal that acts to alter development or function of a target tissue
in multicellular organisms, one of many types of secreted chemicals that are formed in specialized cells, travel in body parts of the organism, changing the target cells’ functioning
tropism
growth response that results in plant organs turning toward or away from stimuli due to differential rates of cell elongation
phototropism
growth in response to a direction light source
bend toward light source
auxin
a term that primarily refers to indoleacetic acid (IAA), natural plant hormone that has a variety of effects, including cell elongation, root formation, secondary growth, and fruit growth
drives asymmetric growth in coleoptiles in response to light
phototropins
blue light receptors
expansins
plant enzyme that breaks the crosslinks (h-bonds) between cellulose microfibrils and other cell wall constituents, loosening the wall’s fabric
PINs
transporters of auxin localized to the cell membrane
requires active transport
gravitropism
directional growth in response to the force of gravity
statoliths
starch granules that sense gravity and settle to the lowest side of cells
a specialized plastid that contains dense starch grains; may play a role in detecting gravity
thigmotropism
a directional growth of a plant in response to touch
hydrotropism
directional growth in a plant in response to water
roots will grow toward a a water source
heliotropism
a symmetrical growth of the stem over the course of the day to follow the relative position of the sun int he sky and then at night reorient back to face at the anticipation of dawn
dormancy
state of slow metabolism and suspended of growth and development
a condition typified by extremely low metabolic rate and a suspension of growth and development
abscisic acid (ABA)
hormone that generally slows growth
a plant hormone that slows growth, often antagonizing the actions of growth hormones; two of its many effects are to promote seed dormancy and facilitate drought tolerance
gibberellins (GAs)
hormone that promotes both cell division and elongation
any of a class of related plant for one’s that stimulate growth in the stem and leaves, trigger the germination of seeds and breaking of bud dormancy and (with auxin) stimulate fruit development
phytochrome
sensors of red and far-red light
plant pigments that absorb mostly red and far-red light and regulate many plant responses, such as seed germination and shade avoidance
red:far-red ratio
indicates shade and what light the leaves have absorbed photosynthetically
shade avoidance
in plants that have a high RFR, they grow shorter than a low RFR
plants crowded out = need to compete
need to grow taller, flower earlier
low R:FR ratio —> more in Pr form
karrikins
specific activating signals in smoke
plant growth regulators in smoke form burning plant material
inflorescence meristem
putting our determinate floral meristems/primordia where it was making leaves
what the SAM becomes
floral meristem/primordia
inflorescence meristem becomes fully determinate
produce the structures present in a flower —> no more self renewing cells
self renewing cells have come to a determined fate
circadian rhythms/clocks
a physiological cycle of about 24 hours that persists even in the absence of external cues
long-day plants
flowering occurs earlier or only when day length is above a minimum threshold
short-day plants
flowering occurs earlier or only when day length is below a maximum threshold
day neutral plant
grows in any amount of sun light during the day; doesn’t care
facultative
capable/promotive of a function but not restricted to a particular function or mode of life
obligate
threshold must be passed in order to grow
florigen
a flowering signal in both LD and SD plants
made in leaves under certain conditions and that travels to the SAM inducing them to switch from vegetative to reproductive growth
external coincidence
florigen gene expression is dependent on the upstream genes that of FT that promote or repress its expression but its regulated by the circadian clock and only function when expressed coincident with light
vernalization
promotion of competency to flower by prolonged exposure to cold
juvenile to adult phase transition
juvenile plants aren’t competent to respond to environmental signals that promote flowering; long juvenile phases are a common obstacle to breeding and production of tree crops
ethylene
a gaseous plant hormone important to ripening fruit and abscission
a gaseous plant hormone involved in responses to mechanical stress, programmed cell death, leaf abscission, and fruit ripening
ripening
process by which a tart, hard, green fleshy fruit becomes sweet and soft to attract animals for dispersal
abscission
detachment at a defined zone
rhizobium
nitrogen fixing bacteria associated with legumes
plant supplies nutrients to the rood nodules and withdraws nitrogen rich compounds from the nodules
striga
witchweed
parasitic plant that ravages over 100 million hectares of cereal and legumes crops annually, causing severe losses throughout Africa and parts of Asia
strigolactones
any of a class of plant hormones that inhibit shoot branching, trigger the germination of parasitic plant seeds and stimulate the association of plant roots with mycorrhizal fungi
PAMP triggered immunity (PTI)
recognize molecules that are very diagnostic of microbes or fungi
the first layer of plant immunity that restricts pathogen proliferation
effector
a pathogen encoded protein that cripples the host’s innate immune system
block the immune signal and response
NLRs (nucleotide binding/leucine-rich-repeat proteins)
recognize effectors or plant proteins that have been altered by effectors
act to elicit immune responses including means of sub cellular resistance and cell-death
hypersensitive response
programmed cell death of infected cells and their neighbors
production of antimicrobial molecules, adding more lignin cell to seal off infection, destruction of cell contents
prevents pathogen spread by depriving it of nutrients
system acquired resistance
methylsalicylic acid to salicylic acid induces this
state of elevated resistance to infection not just by the triggering pathogen by all pathogens
methylsalicylic acid
infect cells release this into the phloem which moves thru the plant to tell the plant there’s pathogens around
