lab 5 Flashcards
leaf lamina
everything branching from stem
sessile vs petiole
sessile = no stalk attaching leaf to stem petiole = attaches leaf to stem
characteristics of true leaves
- complex vasculature
- leaf gap
- lateral shoot bud or axillary bud (everything distal to this bud counts as one leaf)
leaf complexity
simple vs compound
leaf arrangement
pinnate vs palmate
opposite vs alternate
leaf venation
parallel vs netted
leaf anatomy top to bottom
cuticle with stomata/guard cells epidermis palisade mesophyll --> light absorption spongy mesophyll --> gas exchange vascular tissue
mesomorphic plants
adapted to moist environments
- single layer epidermis with thin cuticle
- epidermis is thicker than hydromorphic
hydromorphic plants
adapted to wet environments
- single layer epidermis
- no cuticle
- vast spongy layer for buoyancy
xeromorphic plants
adapted to dry environments
-super thick epidermis and cuticle
tricones
stuff in stomata that protect from water loss and predation
syringia
mesomorphic
lilac
Nymphea
hydromorphic
water lily
sclerid cells = lignified for support
stomata only on upper epidermis bc that side’s exposed
nerium
xeromorphic
stomatal crypt = creates humid environment to prevent loss of water vapor
Pinus
xeromorphic
- small “leaves” (pine needles) prevent water loss
- resin ducts carry protective resin substance
- endodermis around vascular bundles w/ suberin (called casparian strips –> regulate water mvmnt)
3 photosynthetic pathways
C3, C4, and CAM
2 types of photosynthetic reactions
Light Dependant
- in thylakoid membrane of chloroplasts
- convert solar energy to ATP or NADPH
Light Independent (Calvin Cycle)
- happens in stroma
- mesophyll cells (bundle sheath cells)
- use energy from light dependent rxns to convert CO2 into glucose and other organic stuff
Calvin Cycle
- Carbon fixation
- CO2 combind=es with RuBP and then splits into 2 3-PGA
- catalyzed by rubisco - CO2 reduction
- ATP and NADPH turn 3-PGA into G3P - Regeneration
- some G3P make glucose, and others are recycled into RuBP
how many calvin cycles to make 1 glucose
6
C3
- most common + energy efficient
- entire calvin cycle (including C fixation) happens in mesophyll cells
Photorespiration = high heat closes stomata –> decreases CO2 and causes O2 buildup –>Rubisco becomes oxygenase –> results in net loss of carbon
C4
- super rare (3%)
- after primary fixation, makes 4-C PEP –> no tendency to bind to O2
- PEP carboxylate turns it into oxaloacetate, then maleet
- maleet is transported to bundle sheath cells
- Rubisco binds to stockpile of carbon in bundle sheath
- spatial separation
- requires more ATP than C3
Zea mays
C4 plant
-has bulliform cells that make leaves curl up during drought
CAM
- suculents/ orchids in dry areas
- use temporal separation of processes
- only open stomata at night
- CO2 is fixed into PEP in mesophyll cells (then oxaloacetate; then maleet)
- maleet is stored inside mesophyll vacuoles
- Daytime: CO2 is released and binds with Rubisco for calvin cycle
sedum
CAM plant
big cells to hold vacuoles
