lecture 9 Flashcards
what are the three main plant adaptations
- adaptation to climate 2. adaptation to low nutrients 3. adaptation to herbivory and pathogens
how do some plants avoid drought
their entire life cycle occurs during periods of rainfall; otherwise theyre dormant
what are some physical adaptations for plants in hot and dry climates
- succulent leaves (water storage tissue) 2. stomata in crypts (inside and have hair filled holes that control air)
what are succulent leaves
water storage tissue
what do plants do in salty soils
they have tissues with high solute concentrations causing lower water potential allowing the plant to take up water counteracting osmosis
what are other xeric adaptations 4 things
- tiny or no leaves 2. shallow roots 3. water storage (enlarged stem) 4. spines help dissipate heat and gives shade
what are spines
modified leaves
what is convergent evolution
similar habitats lead to similar adaptations , some species may look the same but they are not
where do carnivorous plants occur most often
in places with high light, high rainfall, but low soil nutrients (sometimes due to acid conditions)
what is important to note about the carnivorous plants diet
they do NOT get energy from insects rather they get nitrogen and phosphorus from them because soil lacks it
legumes have a symbiotic association with
nitrogen fixing bacteria to supply their nitrogen
plant adaptation to low light
get taller
plant adaptation to excess rain
they have drip tips (shape of leaf) and they have wide thin leave so water doesnt weight them down
plants have what two types of responses towards herbivores and pathogens
they have induced defenses and constitutive defenses
what is an induced defense
those produced in reaction to the presence of the pathogen, herbivore, or threat
what is a constitutive defense
those always present in plants
what are five examples of constitutive defense
- outer surface (cuticle, bark, etc) 2. trichomes (hairs may be sharp or dense) 3. laticifers (latex channels) 4. thorns or spines 5. secondary metabolites (substances not essential to plant)
trichomes
hair, may be sharp, and dense hairs may make obscure epidermis
laticifers
latex channels that can gum up mouth of insects and can have toxins
thorns
modified stems
spines
modified leaves
secondary metabolites
substances not essential to plants like toxins , chemical warfare to repel threats
what is an example of a secondary metabolite
canavanine: a non protein amino acid that looks like an essential amino acid produced by some legumes and poisons herbivores
secondary metabolites can be used as
drugs like nicotine, thc, medicines, and flavoring properties
what is rubisco
an enzyme that fixes co2 in light independent reactions
when stomata opens what happens to rubisco
its exposes to relatively high concentrations of c02 because 02 can be released in atmosphere
when stomata closes what happens to rubisco
its exposed to high concentrations of o2 and low co2 because 02 isnt being released and rubisco starts fixing oxygen instead of co2 (not good)
what is the process of rubisco fixing oxygen called
photorespiration
how can a plant keep stomata closed to conserve h20 but keep photosynthesis
by protecting rubisco from photorespiration by actively concentrating co2 around it
how can a plant keep photosynthesis happening in not bright and dry places (2 answers)
- protect rubisco from photorespiration by surrounding it with co2 (c4 photosynthesis) or 2. concentrate co2 and restrict h20 loss by closing stomata during the day and opening at night (CAM photosynthesis)
c4 photosynthesis
associated with kranz anatomy which isolates rubisco to the bundle sheath (changes in leaf structure), mesophyll cells turns c02 into malate which is then moved to the bundle sheath to turn back into co2 around rubsico (surrounds rubisco with c02)
CAM photosynthesis
cam photosynthesis stores co2 as malate at night (like c4) stomata opened and used co2 during the day with stomata closed
species that use CAM can do what special thing
they can switch the alternative pathway on or off depending on the need
cAM has NO what
anatomical change to the leaf
