2. Temperatures
Tair= 22oC
Human
Homeotherm: Able to
maintain constant body
temperature through
metabolism.
Cucumber plant
Poikilotherm: Unable to
maintain constant body
temperature through
metabolism.
3. Temperature & Plant Life
Temperature influences:
Which
• Plant metabolism:
temperature?
Photosynthesis
Dark Respiration
The temperature
• Plant growth experienced by the
• Plant development
plant!!!
4. Temperature & Plant life
The fact that poikilotherms cannot maintain constant
temperature does not necessarily imply that their body
temperature will always be
equal to air temperature...
5. Meristem function and temperature
Temperature
Perception Response
Meristem Function Organogenesis
6. Meristem temperature differs from air temperature:
depending on radiation and species
5
25
23
3
Tmeristem (oC)
21
1
19
-1
Day Night
(a) 17
-3 (b)
Cucumber
23
3 Tomato
15
Tmeristem (oC)
-5
-100 0 100 200 300
21
1
Rnet (W m-2)
-1
19
7. Meristem temperature differs from air temperature:
depending on vapour pressure deficit and species
Day Night
(a) (b)
Cucumber
23
3 Tomato
Tmeristem (oC)
21
1
-1
19
17
-3
0.2 0.5 0.8 1.1 0.2 0.5 0.8 1.1
VPD (kPa) VPD (kPa)
8. Conclusions
• Meristem temperature differs substantially from air
temperature depending on other environmental factors
• Meristem temperature differs between species
• If we are to properly estimate/model the effects of the
environment (e.g. climate change impacts) on plant
development, meristem temperatures should be quantified
instead of air temperature