Plant response to temperature change
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Transcript Plant response to temperature change
Plant response to
temperature change
Hot environments
Plants need radiant energy from the sun
to photosynthesise, but needs to
remove most of this heat so as to
maintain an optimum temperature.
Removing heat
Radiates heat into environment
Transpiration
Evaporation of water from leaf
surface (transpiration)
The air around plant is heated by
plant and rises, taking heat away
(convection)
SA:V ratio of leaf increased. Also, Convection
Radiation
more “edges” means more cooling
Heat shock proteins produced at
about 40 C to protect enzymes etc
Removing heat cont…
Leaf orientation – turn side on to hot
sun
Water storage in thick trunk
Loss of leaves in summer/heat = no
stomata = no transpiration
Cold environments
Ice forms around cells in freezing
temperatures
Does not form inside cells, as there is a lot of
salt dissolved in there, which reduces freezing
point
Water comes from cells doing metabolic
processes
Ice shards pierce cell wall, but push cell
membrane inward, leaving cell intact
If there is a MASSIVE drop in temperature, ice
will form inside cells and kill the cells
Some plants (eg. Balsam Fir) can live in
temperatures down to -80 C
Activities
Glossary words: transpiration, heat
shock proteins
Quick Check questions pg 325