Plant Nutrition

Question 1

Source of plant nutrients

Answer 1

Dissolved nutrients in plant soil

Question 2

Macronutrients

Answer 2

Main 3: C (CO2), O (CO2), H (H2O)
Rest: N (NO3- or NH4+; organic material), K (K+; rock minerals), Ca (Ca+2; rock minerals), Mg (Mg+2; rock minerals), P (H2PO4- or HPO4-2; organic material), S (SO4-2; organic material)

Question 3

Micronutrients

Answer 3

Act as enzyme activators or cofactors
Come from minerals in soil
Cl, Fe, Mn, B, Zn, Cu, Ni, Mo

Question 4

How to determine which nutrients are essential for plant growth

Answer 4

Control solution: solution containing all minerals
Experimental solution: solution without a certain mineral
See effects of lack of mineral on plant growth

Question 5

Chlorosis

Answer 5

Lack of chlorophyll in a plant
Phosphate deficient: can see anthocyanin (purple color)
Potassium or nitrogen deficient: can see carotenoids (yellow-orange color)

Question 6

Mobile nutrient

Answer 6

Can move in plant

Nitrogen deficient: can see in old leaves (nitrogen travels to new leaves)

Question 7

Immobile nutrient

Answer 7

Cannot move in plant

Iron deficient: can see in young leaves (iron is confined to old leaves)

Question 8

Epiphyte

Answer 8

Slow growing plant

Grows on other plants and symbiotically gains nutrients from them

Question 9

Photosynthetic parasite

Answer 9

Taps into xylem of other plants
Limited nitrogen: high transpiration
Example: mistletoe

Question 10

Carnivorous plants

Answer 10

Acidic soils with low nitrogen: make up for lack of nutrients by consuming other organisms (usually insects)
Example: pitcher plant

Question 11

Components of soil

Answer 11

Water (25%)
Rock (45%)
Organic material (5%)
Air (25%)
Pore space: water and air

Question 12

Tropical forest soil

Answer 12

Red in color (high iron content)
Deep (lots of weathering)
Organic material content low (lots of decomposition)

Question 13

Prairie soil

Answer 13

Dark color
Not as deep
Lots of organic material: good for growing crops

Question 14

Soil forming factors

Answer 14

"TROPC"
Time (younger soil-richer)
Relief (topography)
Organisms
Parent material (rock material that underlies soil)
Climate- temperature and rainfall

Question 15

Cation exchange complex

Answer 15

Soil particles are negatively charged on the outside
Cations are attracted to the outside
Plant secretes H+ that displaces other cations, so they can be absorbed by the plant

Question 16

Nitrogen fixation

Answer 16

Done by rhizobium (bacteria)
N2 + many ATP molecules -> NH3
Nitrogenase (enzyme secreted by rhizobium) catalyzes reaction
Leghemoglobin (iron-containing protein) regulates oxygen supply in reaction

Question 17

Nitrogen cycle

Answer 17

Reactions mediated by bacteria
N2 or organic material -> NH3
NH3 + H+ (from soil) -> NH4+
NH4+ -> NO3- (absorbed by plant)
Leftover NO3- -> N2

Question 18

Formation of nodules

Answer 18

Chemical signals from root attract bacteria, which cause infection thread
Bacteroids form from infection thread in root
Growth of bacteroids continues and a root nodule forms
Nodule develops vascular tissue

Question 19

Mycorrhizae

Answer 19

Mutualistic relationship of fungus and plant
Increased surface area: increased absorption
Generally facultative
Can stimulate growth

Question 20

Endomycorrhizae

Answer 20

Penetrate cell wall, but not plasma membrane

Corn, wheat

Question 21

Ectomycorrhizae

Answer 21

Penetrate roots, but in between cell walls

Pine, oak, maple (truffels, morels)

Question 22

Mantle

Answer 22

Fungal sheath formed by micorrhizae