Obtaining Essential Resources

Question 1

Important developmental cues

Answer 1

Germination shoot elongation
Orientation
Flower initiation

Question 2

Photosynthesis

Answer 2

Capture of energy from light uses to convert CO2 to physiologically useful carbon compounds

Question 3

Positive net photosynthesis

Answer 3

When plants have enough light and can successfully photosyntesize (some plants have higher or lower saturation)

Question 4

Photosythetically active radiation

Answer 4

Wavelengths between 350 and 700nm. Driven by the absorbance spectrum of chlorophyll and other photosynthetic pigments

Question 5

Light competition

Answer 5

Intercept light before your neighbor does

Question 6

What size plants intercepts more light?

Answer 6

Bigger plants

Question 7

Light competition is ____________

Answer 7

asymmetric (plant only has to be a little taller

Question 8

Competitive strategies for light competition

Answer 8

taller plants
growing faster
bigger leaves
low investment in leaf structure
low light tolerance
avoidance of shading

Question 9

Tolerating low light strategies

Answer 9

shade adapted leaves
specialization on shorter wavelengths that can penetrate the canopy
changes in leaf structure to take advantage of light from different direction

Question 10

Examples of shading avoidance

Answer 10

Wild leeks/ramps, downy yellow violet, heart-leaved foamflower

Question 11

Carbon dioxide

Answer 11

rare component of atmosphere (below 0.035%, 408ppm and rising 2-3ppm per year)

Question 12

What happens when there is too little CO2?

Answer 12

plant will fix O2 instead (photorespiration), which reduces photosynthesis 30-50%. Not really useful to plant

Question 13

Transpiration

Answer 13

Movement of water from soil through plant vascular system and out stomata

Question 14

Opening stomate to obtain CO2 _______ the plant water

Answer 14

costs

Question 15

Why do plants close stomata during hottest part of day?

Answer 15

to reduce water loss

Question 16

C3

Answer 16

• Most common photosynthetic pathway
• stomata open during sunny parts of the day making plant dependent on abundant transpiration water

Question 17

C4

Answer 17

• Carbon storage and internal transfer
• carbon concentration mechanisms to avoid photosynthesis

Question 18

CAM

Answer 18

• Crassulacean acid metabolism
• CO2 captured at night, stored as malic acid

Question 19

C3 ideal climate

Answer 19

cooler, wetter climates

Question 20

C4 ideal climates

Answer 20

warmer, dryer climates

Question 21

Belowground resources

Answer 21

Water, micronutrients, macronutrients

Question 22

What do macronutrients limit?

Answer 22

plant growth and productivity

Question 23

What do micronutrients limit?

Answer 23

limit growth of certain species depending on requirements

Question 24

Water avalibility depends on….

Answer 24

supply and infiltration

Question 25

Root stratagies for obtaining water

Answer 25

root deeply or high root density

Question 26

Plants can tolerate drier conditions if they can retain ______ water

Answer 26

more

Question 27

Plants can access more water if they root _____ deeply

Answer 27

more

Question 28

nutrient uptake is _______ in dry conditions

Answer 28

limited

Question 29

Nutrient uptake depends on

Answer 29

how much is availible
frequency of deposition

Question 30

Traits associated with nutrient uptake

Answer 30

root system architecture
root foraging precision
nutrient uptake kinetics
interactions with microbes

Question 31

Essential macronutrients

Answer 31

Nitrogen, phosphorous, potassium, calcuim, magnesium, sulfur

Question 32

Essential micronutrients

Answer 32

chlorine, iron, manganese, boron, zinc, copper, mickel

Question 33

Nutrients generally have a ______ _________ in the soil

Answer 33

patchy distribution

Question 34

How do nutrients get to the roots?

Answer 34

Diffusion and mass flow

Question 35

Diffusion

Answer 35

• Slow
• Along a concentration gradient where root needs to be very close to take stuff up
• Important for P, Mg, Ca, and most micronutrients

Question 36

Advantages of intensive root use

Answer 36

Fast
Effective for capturing ephemeral (short time) resources
no need to spend energy of building new roots

Question 37

Disadvantages of intensive root use

Answer 37

Plants have to have roots in the right place (cannot reach new patches)
cannot displace competitors

Question 38

Advantages of selective root growth and death

Answer 38

live roots use energy, so energy is saved by eliminating less productive ones
adjusting time of death
can take some nutrients back from roots

Question 39

Disadvantages of selective root growth and death

Answer 39

slow relative to physiological adjustment
loss in investment when roots turnover

Question 40

Root proliferations

Answer 40

rapid production of new roots in nutrient rich patches

Question 41

Precise foraging

Answer 41

requires less upkeep because roots are only placed where they are useful
allows plants to take advantage of unpredictable and spatially heterogenous resources

Question 42

Imprecise foraging

Answer 42

Allows plant to intercept resources, but has a greater upkeep cost
roots need to be in right place to find the resources in the first place

Question 43

Root competition

Answer 43

symmetric because bigger plants dont have an advantage