-
Endodermis: function
Gate keeper
-
Waters pathway into the plant
endodermis
-
Transmembrane
within cells (water channels)
-
Aploplastic
- Outside cells (outside membrane)
- low resistance
-
symplastic
within cells (plasmodesmata)
-
water is forced through the cell membrane at the ____
endodermis
-
Casparian strip
wall the water must be filtered through between cells
-
Theories of water transport up trees
- root pressure
- capillary action
- cohesion tension
-
root pressure
- water pushed upwards from roots
- root cells actively accumulate ions
-
capillary action
- thin tubes
- meniscus of water (adhering to cell wall)
-
cohesion tension
- hydrogen bonds pull each individual atom upwards as evaporation occurs
- must have evaporation
-
-
guttation
liquid water expelled by leaves (dew)
-
cohesion
water molecules stick to each other
-
adhesion
- water molecules stick to cell wall
- Transpiration
- pull created by transpiration transmitted down to the roots by hydrogen bonds
-
Tree trunks ____ when transpiration is highest
shrink
-
High presure means____
low water potential
-
Plant conundrum
- need CO2 from air to make food
- maximise exposure to air
- air steal water
- minimize exposure to air
-
Stomata on ____ of leaf
bottem
-
stomatal crypts
open space where guard cells regulate particle flow
-
Stomata cause __% water loss
90
-
Stomata control____
transpiration rate and gas exchange
-
stomata open triggered by_____
- light
- low CO2
- Internal clock
-
Stomata cloing triggered by___
- Drought
- High temperatures
- Internal clock
-
Water potential in guard cells___
changes
-
Proton gradient
contol guard cells water potential
-
Stomata: opening needs
- ATP to pump H+
- K+ to compensate for lost H+
-
Low water potential due to loss of K+ causes_____
- water inflow and swelling
- (turgid)
-
Stoma Close when ____
- K+ leaves
- water potential lowers outside cell
-
C4 photosynthesis
- CO2 concentrated as 4-C compound
- Spatial seperation of CO2 uptake and fixation
-
Phloem
transports sugar from leaves to other parts of the plant
-
Flexible system
direction of flow can change
-
sugar flows from___to____
source to sink
-
source
photsyenthetic structure that produces sugar
-
Sink
stores and uses sugar
-
phloem sap: components
- up to 30% sugar
- minerals
- amino acids
- hormones
- water
-
Active transport: purpose
loads sugar into companion cells/seive tube members against concentration gradient
-
Low water potential at_____
Seive tube members (STM)
-
Water flows____ creating pressure
from xylem
-
Proton pumps located on_____
companion cells
-
Path of sugar
- Pressure at source
- Bulk flow to sink
- Sugar removal at sink
-
Phloem unloading into growing leaves
sucrose breakdown allows passive unloading
-
Sugar in roots is stored in____
vacuoles
-
Plants are made mostly of_____
water
-
Wet weight
- amount of water
- 80-85% weight of plants
-
Dry weight
non-water based components of plants
-
95% dry weight
- Carbohydtares
- Cellulose (C,H,O)
- Proteins and DNA
-
5% dry weight
Inorganic material
-
essential nutrients
- required to complete the life cycle of plant
- known component in specific structure
-
Macronutrients
- fundemental building blocks
- (C,H,O,P,S,K,N,Ca,Mg)
-
Micronutrients
- Trace Catylyst enzymes of cofactors
- <.01% of plants
-
Nutrient diffecient creates___
visible symptoms
-
Hydroponics
grown in solution rather than soil
-
Copper
essential nutrient
-
Mobile nutrients
- deficiency appears in older leaves
- (can move nutrient needs around plant structure)
-
Not Mobile
- Deficiency appears in yong leaves
- cannot move nutrients
-
Fertalizer
adds essential nutrients to soil
-
Need for N in fertlizer
- makes proteins
- nucleic acids
- amino acids
-
Need for P in fertalizer
- sugar phosphate
- backbone of nucleic acids
- makes phospholipids for membrane
- ATP
-
Need for K in fertalizer
regulates cellular waste balance
-
-
-
Soil properties
- texture
- pores for air and water
- nutrients avalable
-
Organic material for soil
- more nutrients available
- water storage
-
Humus
organisms create organic matter
-
2 types of soil that have a negative charge and bind cations
-
Sand: disadvantage
- water drains through
- poor capacity for cation exchange
-
Sand: Advantage
- many air containing spaces
- doesn't pack tight
-
Clay: disadvantage
- few air containing spaces
- Packs tight
-
Clay:Advantage
- holds water well
- large capicity for cation exchange
-
Organic matter: advantage
- holds water well
- large source of nutrients
- high capacity for cation exchange
- contains many air spaces
- doens't pack tight
-
Organic matter: disadvantage
None
-
Mineral uptake occurs thorugh_____
root hairs
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