Chapter 37: Plant Nutrition

Question 1

Photoautotroph

Answer 1

an organism that uses energy from the sunlight to make organic molecules (building blocks) from inorganic ones

Question 2

Heterotrophs

Answer 2

organisms that must ingest food to have organic molecules to fuel, build, and support the whole organism.

Question 3

What process drives water, mineral and nutrient uptake?

Answer 3

transpiration

Question 4

Where does soil originate from?

Answer 4

weathering of solid rock

Question 5

What kinds of weathering are there?

Answer 5

physical, chemical, biotic

Question 6

temperature changes, freezing, thawing, erosion are examples of this kind of weatering

Answer 6

physical weathering

Question 7

acids in soil, changes in pH, acid rain are examples of this kind of weathering

Answer 7

chemical weathering

Question 8

roots creating cracks, secreting acids and enzymes are examples of this kind of weathering

Answer 8

biotic weathering

Question 9

Layers of soil in various stages of development

Answer 9

soil horizons

Question 10

Composed of partially broken-down rock that serves as the parent material for upper horizons

Answer 10

C horizon

Question 11

Soil midway through development. It contains the least organic material and is less weathered than A horizon

Answer 11

B horizon

Question 12

This is the “top soil” a mix of broken down rocks, biota, decaying organic matter

Answer 12

A horizon

Question 13

what is soil texture dependent on?

Answer 13

soil structure

Question 14

If a soil has large particles, they will also have…?

Answer 14

larger air spaces

Question 15

what do air spaces do?

Answer 15

Allow for drainage

Question 16

humus

Answer 16

soil organic matter (SOM)

Question 17

what does organic matter (humus) help with?

Answer 17

helps soil hold more water and negatively charged nutrients

Question 18

What is humus composed of?

Answer 18

plant waste (leaf litter, bark), animal waste, partially decomposed plant and animal bodies

Question 19

what does it mean to “sorbp”

Answer 19

to hold onto

Question 20

Where does the soil nutrients come from?

Answer 20

weathering rock, decomposition of soil organic matter

Question 21

if the nutrients is not dissolved in the soil, what are they doing / where?

Answer 21

attracted to the oppositely charged substances

Question 22

Which ions are attracted to soil particles?

Answer 22

cations

Question 23

Why are anions easy for the roots to take up?

Answer 23

because they are not attached to the soil particles

Question 24

Whats the downside to the anions of the soil?

Answer 24

since they are not attached to the soil particles, they are more susceptible to leaching by rainfall

Question 25

How are cations that are attached to the soil particles released for uptake by the plants?

Answer 25

cation exchange

Question 26

What types of cation exchange are there?

Answer 26

Expensive and Cheap

Question 27

What is the expensive cation exchange entail?

Answer 27

the root of the plant pumps out hydrogen ions (protons) by using ATP, to displace the partial positive cation on the soil particle. By displacing this molecule, they trade. The plant takes the nutrients, while the soil takes the proton

Question 28

What is the cheap cation exchange entail?

Answer 28

Using a by-product of cellular respiration, CO2, it combines with water to form carbonic acid and bicarbonate and hydrogen ions. They exchange the protons just like in the expensive way...except they didn't have to use energy

Question 29

since roots are pumping protons out, what are they doing to the soil pH?

Answer 29

Making it more acidic