Plant biology 1 Flashcards
who won the nobel prize for developing resistant, high yield grain?
Normal Borlaug
what is a perennial plant?
lives more than 2 years
what is willow a source of?
aspirin
what does foxglove have a treatment for?
digitalis - cardiac problems
what is pacific yew a treatment of?
taxol - cancer
what does the cinchona tree bark contain and what for?
quinine - kills plasmodium
what are CAM plants adapted to?
dry climates
what are plants descended from?
cyanobacteria and eukaryotic ancestor
what were the 1st plants?
glaucophytes
what two examples do the glaucophytes contain?
red algae - rhodophytes, green algae - chlorophytes
what photosynthetic accessory pigment do rhodophytes contain?
phycoerythrin - can change colour
what did land plants evolve from?
green algae
what were the main challenges of land plants?
desiccation and high UV
in charophytes, what prevented exposed zygotes from drying out?
sporopollenin
what do all land plants have? (4 things)
multicellular dependant embryos
walled spores produced in sporangia
apical meristems
multicellular gametangia
how are nutrients transferred from parent to embryo?
placental transfer cells
where are apical meristems found?
the tip of the root and shoot (the apices)
what do land plants also have?
cuticle
mycorrhizae
secondary compounds
what are non-vascular land plants called?
bryophytes
there are poikilohydric, what does this mean?
lose and gain water to environment
what are the 3 main groups of the bryophytes?
liverworts (hepaticophyta)
the mosses (bryophyta)
hornworts (antherocerotophyta)
which bryophyte group has sphagnum and what does it form?
the mosses, peat
what are non-vascular plants characterised by?
uptake of water by capillary action
name the seedless vascular plants
lycophytes and pterophytes
where are seedless vascular plants found?
tropics and temperate forests
what are living vascular plants characterised by? (3 things)
dominant sporophytes
vascular tissues
well developed roots and leaves
who looked at nature ‘from a global perspective’ and came up with isotherms and isobars?
alexander von humboldt
who said that life forms are related to temperature and moisture?
de candolle
what is a biome?
a group of similar ecosystems
what adaptations do plants have to an arctic tundra? (5 things)
small in size low temperature optima solar tracking freezing tolerant (antifreeze) dormancy
what adaptations do plants have in a rainforest? (4 things)
large leaves with drip tips
prop roots (support)
epiphytism
carnivory
what adaptations do plants have in a desert? (5 things)
succulence photosynthetic specialisation high temperature optima light reflecting surface annual life cycle
what is the world’s largest wetland?
pantanal - brazil
where are the stomata on floating plants?
upper surface
when does an algal bloom occur?
ammonia and nitrogen deposits leached into rivers and lakes
what are the trophic categories?
ultra-oligotrophic oligotrophic mesotrophic eutrophic hypertrophic
when is denitrification a problem?
anaerobic, water logged soil
what is the light compensation point?
carbon fixation balances carbon lost by respiration
what adaptations do plants in water-logged areas have? (4 things)
small thin leaves
thin cuticle
chloroplasts in outer layers
stomata non-functional
what is aerenchyma?
tissue with air spaces, allows diffusion of air from root to shoot
what adaptations do plants have in salt water? (3 things)
stilt roots, pneumatophores allow oxygen in
seeds germinate on tree
leaves excrete salt then shed leaves
name 3 aquatic plants
bladderwort (Utricularia vulgaris)
chara
Nuphar lutea
what leaves can take up nutrients from the air?
epiphytes
what is Liebig’s law of limiting minimum or factors
resource in shortest supply may limit growth/survival
what does nitrogenase do
fix nitrogen in root nodules
where do metalophytes grow
in soils rich in heavy metals
what are the 3 mechanisms for movement of nutrients?
interception
mass flow
diffusion
when was the ‘little ice age’?
1300s to 1700s
how do plants deal with drought? (2 things)
resistance - ‘hardening’
avoidance - store water, deep roots, long time as seeds
how do plants deal with low temperature stress?
avoidance - annuals, plants die back
resistance - change physiology, acclimatisation
what are the two types of toxic chemicals do plants release?
glucosinolates
cyanide (cyanogenic glycosides)
mammalian toxicity is present in what plant?
asclepias (milkweed)
what are the 4 types of carnivorous plant traps?
sticky surface traps
suction traps
pit fall traps
triggered traps
what is the timing of which a suction trap shuts?
10-15 ms
what are the evolved features of pit fall traps?
leaf curling
loss of cuticle
bright colours
hairs point down
when should the hairs of a venus fly trap be triggered for it to close?
twice within 20 seconds
name an obligate parasite
striga hermonthica - witchweed
name a holoparasite
broomrape
name a facultative parasite
rhinanthus minor - hay-rattle
who was described as the ‘founder of phenology?
robert marsham
how do auxins act?
loosen cell wall, promote growth by regulating cell differentiation
what has more storage reserves, annuals or perennials?
perennials - slower growth and more stress tolerant
what happens in the reproductive phase?
hormonally induced shift in response to day length and temperature
what do monocarpic plants do?
flower once then die
what affects seeds success rate?
size
dormancy
environment
how can fruits be dispersed
wind or sea
what do environments select for in seeds?
size
number
why do enclosed habitats produce larger seeds than open habitats?
dispersal - small seeds dispersed easily by wind or gravity
probability of dispersal - better to produce large numbers of small seeds when possibility of drought/environmental risks
what can break dormancy in seeds?
light
fire
rain
what can trigger dormancy?
phytochrome
what requires 6-8 weeks of vernalisation below 5 degrees celsius?
rhinanthus minor - hay rattle
