NPP and allocation

Question 1

why are terrestrial plants important to NPP

Answer 1

life zone, precip

Question 2

describe life zone

Answer 2

Life zone – volume of space an organisms can potentially occupy. The ocean has a
greater volume, however terrestrial plants outweigh the ocean in terms of productivity
because they are not nutrient limited like oceans.
Coastal terrestrial areas have increased primary production because they are moist
and have more rainfall.

Question 3

describe npp and precip

Answer 3

verall trend of increasing temperature, increases primary production
(excluding deserts)
- Quadratic relationship meaning once you get 2000 mm of rain, there is
a decreases in primary production
- Too much water = saturated reduces the availability of oxygen to the
roots creating water logging thus they stop up taking water and grow
slower. Increases water also create deficiency of nutrients because
draining through profile (especially phosphorus)

Question 4

Describe the praries and NPP

Answer 4

the prairies have relatively fast primary production because of being adapted to a short growing
season

Question 5

why are species limited in enhancing PP

Answer 5

species are adapted to their local conditions such that they can’t use extra resources creating
limitations because they don’t have the mechanism to enhance PP

Question 6

what creates NPP variation

Answer 6

Precipitation – spatial variation depending on where the biome is located has different
levels of precipitation while temporal variation does not respond to additional
precipitation due to adaptations

Question 7

describe precip variation by location

Answer 7

• Dry locations are limited by water such that not enough water
  decreases PP
• Wet locations are limited by water such that too much water decreases
  PP; limited by oxygen
• Tropical forests are limited by phosphorous because it is drained out of
  the soil

Question 8

what happens to NPP within a plant (4)

Answer 8

1. Growth within plant it takes 40 -70% of net primary production
   New roots (30-40%,) ; leaves (10-30)
2. Root secretions use 20 to 40% of net primary production
   Transferring to mycorrhizae (10-30%), root exudates – nutrients released (leaked)
   into soil usually sugars (might be selecting for specific microbes) (10-30%)
3. Losses to herbivores, mortality, and fire (1-40%)
4. Volatile emissions (0-5%)

Question 9

how is NPP allocated?

Answer 9

Allocation to different parts influences survival, growth, and
reproduction

Question 10

functions of structures that plants allocate to?

Answer 10

Leaves – Photosynthesis
Stem – Support
Roots – Uptake of nutrients and water
Flower and seed – Reproduction

Question 11

how do we measure NPP allocation

Answer 11

Root: Shoot Ratios
How plant allocate efforts: Response of plant to
Minimize limitation of nutrients = grow roots
Minimize limitation of access to sunlight = grow shoot

Question 12

how does allocation change?

Answer 12

seasonal, leaf budget

Question 13

describe seasonal change

Answer 13

esources and energy that would normally go onto leaves gets
absorbed into plants and stored for next year’s leaf growth

Question 14

describe leaf budget change

Answer 14

on individual level making localized decisions (keep or drop leave)
depends on whether the maintained cost greater than benefits of maintain it = leaf will be
dropped (allocate energy to other parts of plant)

Question 15

how do biomes differ in tissue allocation of growth

Answer 15

Tropical forests and boreal forests – allocation to below ground (20%)
Deserts and grasslands – allocation to below ground (50%)

Question 16

good vs bad growth conditions- allocation

Answer 16

Good growth conditions – primary competition is less – more shoots
Bad growth conditions –increase completion of resources – more below ground