TRansFOROP

Question 1

where are aquaporins in phloem
function??????????????????????????????????????????????????

Answer 1

• The aquaporins in the plasma membrane of the sieve elements
  -help control flow of water in and out of sieve tubes

Question 2

Munch pressure flow hypothesis

Answer 2

phloem
- Pressure flow hypothesis states that phloem sap (water+sugar) is moved by pressure gradient

• Maintained by loading at source and unloading at sink

Question 3

Phloem Loading source

Answer 3

-Phloem loading creates high sugar conc at source, water enter phloem via osmosis, creating high pressure(turgor)

Question 4

Phloem loading sink

Answer 4

At sinkm sugars unloaded, water exits as well

Question 5

Apoplasmic loading

Answer 5

○ Active transport of sugars from apoplastic(cell wall) into companion cell

○ Sugars unable to leak back to bundle sheath--> no plasmodesmata Most herbs

Question 6

Symplasmic loading

Answer 6

○ Sugar follows downhill conc gradient from bundle s. to phloem

○ Cells connected via plasmodesmata

○ Most water comes from xylem Most trees

Question 7

Callose

Answer 7

shits that form around pores that have damaged sieve tubes

Question 8

phloem sap content

Answer 8

-sugar(mostly sucrose(20%), amino acids, RNA, viruses, hormones

• Some signals may be transmitted through phloem sap

Question 9

Cohesion tension theory

Answer 9

xylem

transpiration Creates a pulling force

- Water pulled up(possible bc cohesion and adhesion)

- Atmosphere pulls harder than soil(much drier, so water wants up)

• Water in xylem is under great tension, xylem sap is metastable

Question 10

how does Embolism happen

Answer 10

• Xylem water under tension = negative pressure
  
  • if sap around bubble under tension, could create embolism by expanding and filling vessel

Question 11

Droughts killing mother fuckers
(prof might put some stupid fucking bullshit on exm)

Answer 11

• Chaparrel shrubs in dieback due to california drought
  Aspen die back cuz of drought in utah

Question 12

Solution to tge embolism

Answer 12

Guttation

Question 13

Root pressure in small herbaceaous

Answer 13

• Water drops on leaf tips
  
  • Guttation

Question 14

Guttation

Answer 14

: water being pushed out of xylem through root pressure
Refills vessels

Question 15

Root pressure in trees and shit

Answer 15

• Root pressure only occurs before leaves emerge in spring
  
  • Because hard to refill vessels way up