PHLOEM TRANSPORT

Question 1

Phloem

Answer 1

source-sink translocation

Question 2

Source tissue

Answer 2

exporting plant tissues or organs that produces photosynthate (source leaf)

Question 3

Sink tissue

Answer 3

non-photosynthetic developing organ (root) or and organ that does not produce enough photosynthate (meristem)

Question 4

Sieve tube

Answer 4

stacked sieve elements
the functional units for long distance translocation of plant materials

Question 5

Nonreducing sugars

Answer 5

can be translocated through the phloem
sucrose, raffinose, stachyose, verbascose

Question 6

Munch pressure flow hypothesis

Answer 6

Sink: solute potential higher, lower turgor pressure
Source: solute potential lower, higher turgor pressure

Question 7

Source-sink transition leaf*

Answer 7

mature and immature parts
leaf base: source
Leaf tip: sink

Question 8

Mature sieve elements

Answer 8

P-proteins
endoplasmic reticulum
mitochondria
sieve elements plastids

Question 9

Mature sieve elements do not contain

Answer 9

nucleus**
vacuole
golgi bodies
chloroplast

Question 10

P proteins

Answer 10

sealing off damaged sieve elements by plugging up the sieve plate pores
short term solution

Question 11

Callose

Answer 11

seal off damaged sieve elements
long term solution

Question 12

Xylem

Answer 12

root-to-shoot translocation

Question 13

Heterotrophic shoot

Answer 13

assimilate sink

Question 14

Autotrophic leaf

Answer 14

assimilate source

Question 15

Symplasmic sucrose loading model

Answer 15

sucrose moves through the plasmodesmata from the mesophyll cells to the phloem

Question 16

Apoplasmic sucrose loading model

Answer 16

SUT: sucrose transporter
phloem parenchyma cell to companion cell

Question 17

reducing sugars

Answer 17

glucose, mannose, and fructose
too reactive

Question 18

translocated through phloem

Answer 18

water
photosynthate
proteins
RNA

Question 19

Sink strength

Answer 19

phloem translocation is controlled by local sink strength