Lecture 23. Thermoregulations and Water Stress in Plants Flashcards
What are the main abiotic factors limiting primary production ?
- Water
2. Temperature stress
What does the inefficiency of photosynthesis result in ?
Under-performance of crop plants
What in plants is inextricably linked ?
Temperature and water loss
What is a solution to the linkage of temperature and water loss ?
The evolution of different photosynthetic pathways to limit stomatal opening in a day
What can plants generate a high amount of ?
Heat
What may cause stress to non-native plants ?
Abiotic conditions to which native plants are adapted
Where are most agricultural crops cultivated in ?
Regions where they are highly adapted
What are the most important abiotic factors that effect plant growth and development ?
- Water
- Mineral elements in soil
- Temperature
- Light
What are the most important abiotic factors in primary production ?
- Temperature
2. Rainfall
Where can terrestrial vascular plants thrive within ?
A wide range of temperature from -5 to 55 degrees celsius
Where are terrestrial vascular plants be productive between ?
5 and 40 degrees celsius
Where are some species such as aquatic algae be specialised for life ?
Narrow but sometimes extreme temperature ranges
Where do ice algae thrive ?
-5 to 5 degrees
Where does maize thrive ?
10 to 40 degrees
Where does thermophillic algae thrive ?
45 to 50 degrees
What is the common pathway that photosynthesis and transpiration share ?
CO2 diffuses in an H2O diffuses out from the leaf via open stomata
How is CO2 converted to sugar ?
Uses rubisco
Where does the photorespiration pathway occur ?
The chloroplast but also mitochondria and peroxisomes
What is a C3 plant ?
The majority of plants - the first carbon compound produced contains three carbon atoms
What do the C3 plants do ?
- Calvin cycle
2. In high temperatures they are at a disadvantage as stomata remain open long and loose water
What are C4 plants ?
Found in hot, dry environments and a four carbon compound is produced
What do C4 plants do ?
- Calvin cycle and CO2 pump
2. Reduced stomatal opening in the day, prevents water loss
What is the function of pepcarboxylase ?
Produces 4 carbon acids
Where are CAM plants found ?
Desert environments
What do CAM plants do ?
- Calvin cycle and CO2 pump
2. Stomata open at night, stores water, highest water use efficiency
What does Arum maculatum do ?
Prior to anthesis, plant produces a cone shaped sheath which contains a foul smelling spadix which traps insects for pollination
What do the mitochondria of the spadix in the Arum maculatum do ?
Produce heat to vapourise and disperse specific amide and indole chemicals that serve to attract insects
What do Symplocarpus foetidus/skunk cabbage do ?
Plants literally melt the snow away from around them by maintaining a temperature of 25 degrees in their immediate vicinity
What is thermogenesis related to ?
An increase in the rate of respiration of the spadix
How many ATP mols are produced for every glucose ?
28
What is the total yield for respiration ?
32 mols of ATP for every glucose equivalent
What can cyanide do ?
Knock out cytochromes
What can knock out an area of the plant membrane that is resistant to cyanide ?
SHAM
