Exam 2 Transport In Plants

Question 0

¥w=¥p+¥s

Answer 0

Total water potential of a plant = pressure potential and solute potential

Question 1

Transpiration

Answer 1

Process where plants absorb water through roots and give off water vapor through pores in their leaves.

Question 2

Water moves from areas

Answer 2

High to low ¥w

Question 3

Adhesion

Answer 3

Attraction between water and polar groups of other molecules

Question 4

Cohesion

Answer 4

Attraction between molecules

Question 5

Water movement through xylem is…

Answer 5

Passive

Neg. pressure in xylem

Question 6

Water evaporates into intracellular spaces and exits the stomatal pores by diffusion :

Answer 6

The concentration of water vapor inside the lead is higher than that of the atmosphere.

Question 7

Opening and closing of the stomata…

Answer 7

Regulates transpiration

Question 8

ABA (abscisic acid)

Answer 8

Plant hormone that triggers closure of stomata.

Question 9

Soil solution

Answer 9

[K+] plant cells&raquo_space;[K+] in the soil solution

Question 10

When they reach xylem,

Answer 10

Minerals move to the shoot with the transpiration stream and are incorporated into the tissues of the shoot

Question 11

Phloem transports organic molecules:

Answer 11

Sucrose, amino acids, and some hormones
Movement is from sources to sinks.
Movement only in one direction.

Question 12

Sources:

Answer 12

Places from where molecules are exported.

Eg. Mature leaves

Question 13

Sinks

Answer 13

Places where import of substance occurs.

Eg. Roots, young leaves, fruits, seeds, growing parts of the plant.

Question 14

Mass flow

Answer 14

Substances move by a difference in hydrostatic pressure between the source (high pressure) and the sink(low pressure).

Question 15

At a source, solutes are loaded into the phloem, drives water into phloem, resulting in

Answer 15

High pressure

Question 16

At a sink, solutes are unloaded, water moves out, resulting in

Answer 16

Water moves out and the pressure is low.

Question 17

Macronutrients obtained from air or water:

Answer 17

C, O, H

More than 1g/kg of plant dry matter

Question 18

Macronutrients obtained from the soil (soil solution)

Answer 18

N, P, S, K, Ca, Mg

Question 19

Micronutrients obtained from the soil ( soil solution)

Answer 19

Cl, Mn, Mo, B, Cu, Fe, Ni, Zn

Less than 100mg/kg

Question 20

Functions of essential elements:

Answer 20

Part of molecules, e.g. N in proteins and Nucleic acids, P in ATP, Mg in chlorophyll, Fe in cytochromes

Necessary for the activity of certain enzymes. E.g. Mg^2+ and Mn^2+ are cofactors for several enzymes.

Osmotic balance, e.g. K+ and Cl-

Question 21

Localized necrosis

Answer 21

Dead tissues, symptom of mineral deficiency. Low K

Question 22

Chlorosis,

Answer 22

Yellow areas in the leaves , low N

Symptom of mineral deficiency

Question 23

Curling of leaves, sign of min. Def.

Answer 23

Low Mg

Question 24

Stunted growth, sign of min. Def.

Answer 24

Low Ca^2+

Question 25

Humus

Answer 25

Decaying organic matter

Question 26

Organic matter helps

Answer 26

In the retention of cations (K+, Ca2+, Mg2+) and represents a reservoir of nutrients

Question 27

Mineral particles

Answer 27

Sand: 20-2000 micrometers in diameter Silt: 2-20 micrometers in diameter Clay: less than 2 micrometers in diameter

Question 28

``` Pores are occupied by water or air. Small particles (clay) help: Large particles (sand) aid: ```

Answer 28

Retention of water and cations | Aid in drainage of the soil

Question 29

Nutrient cycle losses; leaching of nutrients

Answer 29

Eg. Loss of NO3- and SO4-

Question 30

Nutrient cycle losses; burning vegetation

Answer 30

Burning liberates N and S as a gas harvesting crops.

Question 31

Replenishment :

Answer 31

Fixation of nitrogen, ex. Symbiotic association between legumes and rhizobia. Addition of fertilizers, inorganic (N, P, K) organic (manure, compost)