Chapter 36

Question 1

Nutritional requirements of plants

Answer 1

Essential nutrients
Macronutrients
Micronutrients

Question 2

Essential nutrient

Answer 2

Element or compound required for normal growth and production

Question 3

Essential nutrients for plants

Answer 3

3 essential elements: C,H, O (96% of dry mass)

14 mineral nutrients: elements found in soil

Question 4

Macronutrients

Answer 4

elements in soil that plants require in large quantities; used to make nucleic acids, phospholipids and proteins

Question 5

Micronutrients

Answer 5

Required in small quantities; function as cofactors of a specific enzyme

Question 6

Limiting nutrients

Answer 6

Nutrients where their availability limits plant growth

Nitrogen, phosphorus, potassium

Question 7

Hydroponic growth

Answer 7

Method used to study effects of nutritional deficiencies

Method: Plant is grown in liquid without soil with availability of nutrients controlled

Question 8

Weathering

Answer 8

Forces applied by rain, water, wind; begins process of breaking down solid rock into soil

Question 9

Humus

Answer 9

decaying organic matter

improves soil fertility, water retention, CEC (cation exchange capacity), nutrient availability, and soil health of the soil

Question 10

How does soil texture effect the soil

Answer 10

Effects penetration of roots, ability to hold H20 and availability of O2

Question 11

Mature soils

Answer 11

Mixture of organic and inorganic compounds

Question 12

Loams

Answer 12

The best soil as it contains humus and has a good mixture of texture

Question 13

Factors affecting nutrient availability

Answer 13

Anions
Cations

Question 14

How does anions affect nutrient availability

Answer 14

High concentrations of anions like nitrate, sulfate, and phosphate increase plant growth while low concentration can limit it

Cause leaching due to anions not being taken up by plants or absorbed onto soil particles which can cause nutrient loss

Question 15

Leaching

Answer 15

Loss of nutrients via movement of water through soil

Question 16

How does cation exchange affect nutrient availability

Answer 16

1. Cation exchange helps release positively charged nutrients to be absorbed by plants which increases the soil’s ability to retain and supply essential nutrients

If too many cations are absorbed the ph increases, which means more acidity which can cause leaching

Question 17

Nutrient uptake

Answer 17

the amount of each nutrient required for the crop to complete its life cycle at a given yield level

Question 18

Zone of maturation

Answer 18

Zone where nutrient uptake occurs

Question 19

How does epidermis and root hair affect nutrient uptake

Answer 19

Increase surface area available for nutrient and water absorption

Question 20

Zone of depletion in soil

Answer 20

Form due to the uptake of soil resources, primarily mineral nutrients and water

Question 21

Proton pumps

Answer 21

Plasma membrane of root hair and epidermis cells contain proton pumps

Move nutrients into cell against the concentration gradient

Establishes electrochemical gradient that makes it possible for roots to absorb cations and anions

Question 22

How do cations enter root hairs

Answer 22

Via ion channels (diffusion)

Require ATP

Question 23

How does the electrochemical gradient established by proton pumps assist plant roots

Answer 23

Makes it possible for plant roots to absorb cations via ion channels & anions via symporters

Question 24

How do anions enter root hairs

Answer 24

via cotransporters (symporters) against concentration gradient

Require ATP

Question 25

Mycorrhizal fungi

Answer 25

80% of plants have this fungi providing increased water and nutrient absorption capabilities, and phosphorus to plants and receive sugar in return

Question 26

Symbiotic mutualism

Answer 26

Both organisms benefit

Question 27

Nitrogen fixation

Answer 27

Bacteria absorbs N2 from atmosphere, converts it to ammonia, nitrates and nitrites which plants can absorb Requires specialized enzymes and cofactors such as nitrogenase and ATP

Question 28

Nitrogen fixation bacteria

Answer 28

Takes up residence inside plant root cells

Question 29

Rhizobium

Answer 29

Bacteria that lives inside pea roots (legumes) and fixes nitrogen from the soil Helps colonize Legume plant roots to form root nodules and in return gains carbohydrates and protection from the plant whose roots they inhabit.

Question 30

Root nodules

Answer 30

Contain nitrogen fixing-rhizobia (provide plant with ammonia in return for sugar & protection)

Question 31

Flavonoids

Answer 31

Compounds produced by the plants that attract rhizobia bacteria

Question 32

Epiphytes

Answer 32

Nutritional Adaptations of Plant Plant or plant like organism that grow in the absence of soil on leaves or branches of other plants Absorb nutrients through leaves from air and rain (mosses, ferns, tropical plants)

Question 33

Parasites

Answer 33

Nutritional adaptation of plants Live on/in another plant and absorb nutrients from the host using haustoria

Question 34

Nutritional adaptation of carnivorous plants

Answer 34

Used modified leaves to trap and kill insects and other animals - absorb prey's nutrients Use carnivory to supplement when low nitrogen availability in soil

Question 35

What makes up most of the mass of a plant

Answer 35

CO2 and oxygen

Question 36

How do plants influence the uptake of cations such as magnesium involving cation exchange?

Answer 36

cation exchange is driven by the release of CO2 by root cells because CO reacts with H2O in soil to produce carbonic acid, which releases protons.

Question 37

How do proton pumps impact potassium uptake?

Answer 37

decrease positive charge within the cell to attract potassium ions

Question 38

A molecule binds and blocks a potassium channel in a plant cell membrane. What would be its effects?

Answer 38

Potassium uptake would be blocked since potassium ions enter cells through facilitated diffusion.

Question 39

Why is the presence of clay particles important in soil?

Answer 39

The negative charges on clay bind to positively charged ions and prevent them from leaching.

Question 40

Where does most nutrient uptake occur in roots?

Answer 40

in root hairs, in the zone of maturation

Question 41

Cation exchange

Answer 41

CO2 is released into the soil by root hairs, binds to H20 and releases carbonate and hydrogen. Then it binds to cations and brings them into the root