adaptions Flashcards
3 types of adapted plants
hydrophytes
xerophytes
mesophytes
what are hydrophytes
water plants
grow sbmerged or portially submerged in water
example of hydrophotes
water lilies
what are xerophytes
live in a area of low water availability
what are mesophytes
live in habitats with adequate water supply
most plants of temp regions are mesophytes
example of mesophytes
most crops
what are the charecteristics of mesophytes
close stomata during night
shed leaves in winter
under ground organs surive winter - bulbs
how to idenitfy picture of hydrophytes
- stomata on upper layer only
- stems and leaves have large air spaces
what do hydrophytes not have
no lignified support tissues are needed cause water is a support medium
whats marram grass an example of
xerophytes
modifications found in maram grass? (4)
rolled leaves
sunken stomata
hairs
thick cuticle
what can some mesophytes be described as
deciduous
what does dedicious actually mean
they lose their leaves
what does the loss of leaves do
reduces transpiration
whats the sink
any region of the plant which stores or uses the product of photosynthesis eg storage root
what are the 4 types of cells in phloem tissues
sieve tubes
companion cells
phloem fibres
phloem parenchyma
what is the transport of soluble organic materials, sucrose and amino acids called
translocation
what is translocation
transport of soluble organic materials, sucrose and amino acids called
what is the function of the sieve tube
transport of organic materials
what are sieve tubes made of
sieve elements
what are the ends of the sieve tubes called
sieve plates
have pores
what do sieve plates containing pores allow
biderectional flow
whats the evidence to support translocation in the phloem
ringing experiments
phloem sampling of aphids
radioactive labelling
radioactive labelling ( evidence to support translocation in the phloem)
c02 labelled with radioactive carbon is supplied to an illuminated plant leaf
radioactive carbon is fixed in the sucrose and translocated to other parts of the photosynthesis
whats the name of an aphids mouthpiece ( evidence to support translocation in the phloem)
stylet
stylet left on but cut off aphids and the sap flows out
what does mass flow theory state
translocation occurs from source to sink
3 arguments against the mass flow theory
1 - rate of translocation is 10,000 times faster than it would be if substances would be moving by diffusion
2 - sieve plates with tiny pores act as a barrier impending flow
3 - sucrose and amino acids move at different rates and in different directions in the same phloem
