Lecture 25: Plant and Soil Nutrition

Question 1

Three levels of soil horizon

Answer 1

A horizon, B horizon, C horizon

Question 2

A horizon:

Answer 2

• decaying organic matter
• broken-down rock
• microbial organisms
• holds nutrients & materials

Question 3

B horizon:

Answer 3

• less weathered material

Question 4

C horizon

Answer 4

rock, “parent material”

Question 5

How do roots acidify soil solution

Answer 5

• with CO2 & H+

Question 6

Cation exchange

Answer 6

• ## H+ ions neutralize soil solution causing cation exchange

Question 7

What absorbs cations

Answer 7

roots, and pH goes down

Question 8

What drives the transport of solutes into the cell

Answer 8

membrane potential (charge separation) and proton gradient

Question 9

Cations are driven into the cell by _______

Answer 9

membrane potential

Question 10

The membrane potential generated by ____ contributes to absorption of ______ by _______

Answer 10

proton pumps; K+; root cells

Question 11

How does cotransport occur

Answer 11

a transport protein couples diffusion of one solute H+ with the active transport of another NO-

Question 12

What is the composition of topsoil and its function?

Answer 12

• composed of “humus”, organic matter made of decaying plant & animal matter & feces of decomposing organisms
• strongly impact soil nutrient availability, water holding capacity, and soil structure

Question 13

true or false: high input agriculture is sustainable

Answer 13

false

Question 14

Major macronutrients of the life cycle

Answer 14

C HOPKNS CAFE MIGHTYGOOD
C, H, O, P, K, N, S, Ca, Fe, Mg

Question 15

function of Carbon, Oxygen, and Hydrogen in plant

Answer 15

major component of organic compounds

Question 16

Nitrogen function

Answer 16

• from NO3- , NH4+
• component of nucleic acids, proteins, hormones

Question 17

potassium function

Answer 17

protein synthesis; water balance, opening of stomata

Question 18

Magnesium function

Answer 18

• component of chlorophyll

Question 19

phosphorous

Answer 19

component of nucleic acids, ATP, coenzymes

Question 20

Sulfure

Answer 20

component of proteins, coenzymes

Question 21

nodules form from ______ in some plants

Answer 21

Rhizobium

Question 22

Process of a nodule forming

Answer 22

1. Bacteria gets a signal and forms an infection thread
2. bacteroids form
3. root hair comes off & root nodule forms
4. nodule develops vascular tissue
5. mature nodule

Question 23

How do soil bacteria provide nitrogen to plants

Answer 23

• Nitrate and nitrogenous organic compounds are exported to xylem to shoot system

Question 24

Types of mycorrhizae

Answer 24

• ectomycorrhizae
• arbuscular mycorrhizae (endomycorrhizae)

Question 25

ectomycorrhizae

Answer 25

- form a sheath around root - don't penetrate the cell; go around

Question 26

Arbuscular mycorrhizae

Answer 26

fungal hypae extend into roots; in most plants

Question 27

Nutritional adaptations in plants

Answer 27

Epiphytes, Parasitic Plants, Carnivorous Plants

Question 28

Epiphytes

Answer 28

- plants grow on other plants - don't have roots in soil or host - nutrition comes from atmosphere

Question 29

Parasitic Plants

Answer 29

- absorb water, minerals directly from host - some lack clorophyll entirely

Question 30

Carnivorous Plants

Answer 30

- photosynthetic, but digest small animals - live in **nitrogen poor soils**