Plant Physiology Flashcards
what are the two types of transport?
- short
- long
what is short distance transport?
movement along the radial axis
what is long distance transport?
movement up and down a plant organ
how do short distance osmotic substances move?
osmotic substances move directly through cell membranes by diffusion
how do short distance symplastic substances move?
symplastic substances can only move from cell to cell by plasmodesmata through the cytoplasm
how do short distance apolplastic substances move?
not allowed in cell— move outside cells through continuum of cell walls
how do long distance substances move?
high to low pressure in the xylem/phloem
what are the 3 types of water movement?
- absorption of water
- roof pressure
- transpiration-cohesion-tension theory
how does the plant absorb water?
- absorbed by root hairs from soil to stele
- endodermal cells actively transport minerals/water to stele
what makes water go through the endodermal cells?
the casparian strip of the endodermis
what are the 3 types of water movement?
- absorption of water
- root pressure
- transpiration-cohesion-tension theory
how does water get absorbed by the plant?
- water goes from root hairs in soil to the stele (osmotically)
- endodermal cells actively transport minerals/water to stele
- xylem to leaf
what makes the water go through the endodermal cells?
the casparian strip of the endodermis
what is root pressure?
water pressure builds up in stele because of mucho concentration of dissolved substances in stele
how does root pressure work?
-pressure pushes water up stem (low success)
root pressure causes what in small plants?
guttation (dew)
what are the walls of xylem stiffened with and why?
lignin to prevent collapse under the negative pressure
what is the movement of water fueled by?
evaporation in leaves
what does the cohesion of water help?
water molecules stick together in xylem and can be pulled long distances (against gravity)
how does the T-C-T theory work?
- water vapor leaves stomata
- water in bundle sheath cells replace that
- water in xylem of vein replace that
what does the T-C-T theory cause?
a partial vacuum in the leaf vein and it pulls water up
what 3 things affect transpiration?
- temp (doubles every 10C increase)
- humidity (hindered if there’s already water in air)
- air currents (good if the air is blowing the humid air away)
where do plants not need gas?
xylem
what to guard cells do?
regulate stomata in leaves
what guard cells are too thicc with water, do they close or open?
open
when guard cells are NOT too thicc with water, do they open or close?
close
what ion changes the osmotic pressure in guard cells?
potassium
what happens when potassium ions are put into guard cells and vice versa?
osmosis of water into the guard cells (h2o follows k+)
*when potassium goes out, water goes out too (copy cat ass bitch)
what drives potassium ions?
active transport (photosynthesis in guard cells)
what influences the stomata movement? (acronym: WAIT.. Light the Co2) sorry that’s the best acronym i could think of
- water availability
- abscisic acid
- internal clock
- temp
- light
- co2 concentration
how does the availability of water affect stomatal movement?
no water=stomata closed
how does the abscisic acid affect stomatal movement?
binds to guard cell receptors and increases potassium permeability (allows potassium to get the fuck out of the guard cells)
how does the co2 concentration affect stomatal movement?
closes the guard cells if there’s more co2
how does the temperature affect stomatal movement?
increase= stomata close because of increased respiration
how does the light affect stomatal movement?
stomata open because blue light makes potassium feel very welcomed in the stomata community (stimulates K+ import)
how does the internal clock affect stomatal movement?
stomata could be controlled by internal clock
what are the 3 plant adaptations?
- xerophytes
- deciduous plants
- cam plants
what are xerophytes?
adapted for dryness
- thiccc leaves
- heavy cuticles
- stomata in pits
what are deciduous plants?
- lose leaves in dry seasons
- stores water in rainy reasons
what are cam plants?
take in co2 at night (stores as carb)
releases co2 during day while stomata is closed
what type of minerals are usually taken in?
inorganic (dissolved salt)
how are minerals taken in?
actively transported in xylem with water to the stele
how is food transported (translocation)?
pressure-flow-hypothesis
what are sources and what are sinks?
source->sink
source: sugars produced
sink: sugar is used
translocation: sugar is actively transported to the PHLOEM by what/where?
the bundle sheath cells at the source
translocation: water follows WHAT into the phloem by WHAT
follows sugar by osmosis
translocation: water pressure builds up in phloem causing what?
the sap gets pushed away from the source
translocation: if the sugar is being demanded, sugar leaves.. and who the fuck follows?
fuckin water
translocation creates a what?
low pressure area
a who???
low pressure area
translocation: sap goes from _____ hydrostatic pressure to ___ hydrostatic pressure
high to low
what at the 4 factors of nutrients in soil?
- mineral content
- ph level
- humus
- symbionts
what is the mineral content consist of?
- parent rock
- size of soil particles
- erosion
what does an acidic ph of soil do?
the hydrogen ions replace other positive ions
what is humus?
organic material of dead organisms
what do symbionts do?
allows for better absorption
what are macro and micro nutrients? (the necessary nutrients)
macro- large amounts needed (Ca, Mg, P)
micro- small amounts needed (Fe, Zn, Mo)
what are two of the symbionts?
microrrhizae- fungi that extracts nutrients from soil for plants
rhizobium- replaces necessary nitrogen (gets carbs from plant in return)
what are hormones?
chemical messengers that do special things;)
what are some specific things that hormones do?
they help..
- growth
- development
- metabolic activity
what are tropisms?
growth responses due to external stimuli
what is the difference between negative and positive tropisms?
positive- grows toward stimulus
negative- grows away from stimulus
young stems have ______ tropisms
positive
if the stem tip is cut, what happens?
growth response NO HAPPEN
if the cut stem tip is put in agar and the agar is places on the stem, what happens?
positive tropism!
what happens if mica is used instead of agar?
no curvature happens
the response to light is because of what in the stem tip?
auxin
how do plant hormones work?
they alter what genes are activated/repressed
what are the 5 plant hormones? (acronym: acaa egg)
- auxin
- cytokinins
- abscisic acid
- ethylene gas
- gibberellins
what is another name for auxins?
indoleacetic acid
what do auxins do?
- cell elongation
- produce fruit without fertilization
- herbicide to kill dicots
what produces auxin?
- young leaves/flowers
- it is also produced in the stem tip and goes to root
what do auxins do to cellulose fibers?
makes the cell wall loosen so expansion can happen
what do auxins activate?
10 genes involved with cell growth
what is apical dominance?
auxin stopping growth and differentiation
where are gibberellins produced?
- young leaves, young seeds, young roots
- highest concentrations in the young seeds
what do gibberellins do?
- promotes hyperelongation i’m stems
- stimulates nutrients for embryo growth
where are cytokinins produced?
roots
what do cytokinins do?
- releases axillary buds from apical dominance
- prevents aging
- causes cell division
what does ethylene gas do?
- ripens fruit
- stops cell elongation
- regulates leaf loss
what does abscisic acid do?
- controls leaf loss
- stops growth in seeds
- closes stomata when the plant has a huge final to study for and it gets stressed
what is a gravitropism?
response to gravity controlled by auxin
what do statoliths do?
controls auxin and controls growth
what is a thigmotropism?
a coiling response to a touch
cells that done touch something continue to elongate
what is photoperiodism?
response of plant to light and darkness
what is a day neutral plant?
a plant that doesn’t give a fuck about the sun and flowers whenever it feels like it
what is a short day plant? (long night)
flower when the light period is short
what is a long day plant?
flower when the light period is long
plants detect dark instead of light using what?
phytochromes
- red light (sunrise)
- dark red light (sunset)
what is the circadian rhythm?
regular day/night cycles
what is resetting the clock?
entrainment- modifying external conditions
