Phloem translocation

Question 1

phloem transports products of photosynthesis from

Answer 1

mature leaves to areas of growth and storage

Question 2

phloem conducts – molecules

Answer 2

signal

Question 3

phloem – water

Answer 3

redistributes

Question 4

phloem extends throughout the plant body and is – with xylem

Answer 4

parallel

Question 5

in trees with secondary growth, the phloem is on the outside of the – and only the inner layer of phloem is functional as outer is crushed by xylem

Answer 5

vascular cambium

Question 6

phloem is removed by removing bark

Answer 6

girdling

Question 7

girdling tree – ceases between root and leaves

Answer 7

sugar transport

Question 8

sieve tube elements

Answer 8

angiosperms

Question 9

sieve cells

Answer 9

gymnosperm

Question 10

store and release food molecules

Answer 10

parenchyma cells

Question 11

protection and strengthen tissue

Answer 11

fibers and sclereids

Question 12

sometimes – (latex containing) for protection

Answer 12

laticifers

Question 13

only – are directly involved in translocation

Answer 13

sieve elements

Question 14

small veins of leaves and primary vascular bundles of stems are typically surrounded by a – which are compactly arranged colorless cells isolating the veins from the intercellular spaces of the leaf

Answer 14

bundle sheath

Question 15

mature sieve elements contain

Answer 15

mitochondria, plastids, smooth ER

Question 16

sieve element’s cell walls are – and thus remain soft and flexible

Answer 16

non-lignified

Question 17

where pores connect to the other sieve elements

Answer 17

sieve areas

Question 18

pore range from

Answer 18

less than 1 to 15 micro m

Question 19

in angiosperms, sieve areas on the end walls can differentiate into – with larger pores and

Answer 19

sieve plates

Question 20

sieve tube elements can connect to form –

Answer 20

sieve tubes

Question 21

in gymnosperms, – cover the sieve areas

Answer 21

smooth ER

Question 22

dive cells contain sugars and organic molecules in a fluid solution

Answer 22

sap

Question 23

sieve tube elements also contain – which are tubular, fibrillar, granular, or crystalline

Answer 23

P proteins

Question 24

P proteins seal damaged sieve elements by plugging off –

Answer 24

sieve plate pores

Question 25

relatively few plasmodesmatal connections to cells except its own sieve element; symplastically isolated from surrounding cells

Answer 25

ordinary companion cells

Question 26

finger-like wall ingrowths of cell walls facing away from the sieve tube elment

Answer 26

transfer companion cells

Question 27

many plasmodemsata connections with bundle sheath cells, well-suited for taking up solutes via cytoplasmic connections

Answer 27

intermediary companion cells

Question 28

ordinary companion cells – loading

Answer 28

apoplastic

Question 29

transfer companion cells – loading

Answer 29

apoplastic

Question 30

intermediary companion cells – loading

Answer 30

symplastic

Question 31

sources are typically mature leaves; others include storage organs –

Answer 31

storage root of beets

Question 32

sinks = – organs including roots, developing flowers and immature leaves

Answer 32

nonphotosynthetic

Question 33

phloem sap can be collected using – natural syringes

Answer 33

aphid stylets

Question 34

most abundant substance in phloem

Answer 34

water

Question 35

sugar in phloem are –

Answer 35

nonreducing

Question 36

typical range of phloem sap

Answer 36

30 cm to 1.5 m per h

Question 37

pressure gradient of bulk flow is established by

Answer 37

loading and unloading of sugars into sieve tubes

Question 38

sieve plate – slows equilibration allowing a standing pressure gradient to exist and to drive flow

Answer 38

resistance

Question 39

sucrose moves from producing mesophyll cells to cells adjacent to the sieve elements in the leaf minor veins, only a few cell diameters

Answer 39

short distance transport pathway = symplastic

Question 40

sugars are transported into the sieve elements and companion cells

Answer 40

phloem loading

Question 41

sugars are translocated away form the source via

Answer 41

long-distance transport

Question 42

– loading requires energy

Answer 42

apoplastic

Question 43

H+-ATPase transports H+ into the apoplast and a – transport sucrose form the apoplast into the sieve element-companion cell complex

Answer 43

sucrrse H+ symporter

Question 44

explains how different solute concentrations can be generated in different adjacent cells connected by plasmodesmata

Answer 44

polymer-trapping model

Question 45

sucrose synthesized in the mesophyll diffuses form the bundle sheath cells into the – via small plasmodesmata

Answer 45

intermediary cells

Question 46

In the intermediary cells, – and – are syntehsized

Answer 46

raffinose and stachyose

Question 47

larger raffinose and stachyose diffuse through the larger plasmodesmata to the –

Answer 47

sieve element

Question 48

– loading can also occur given high enough sugar production rates

Answer 48

passive

Question 49

in dev leaves, first whole leaf is a sink and sugars are unloaded from the – in the unexpanded leaf

Answer 49

major veins

Question 50

as leaf matures, major veins spaced apart and – dev between them

Answer 50

minor veins

Question 51

when unloading ceases and loading begins only in –

Answer 51

minor veins

Question 52

signal molecules are – from sources

Answer 52

loaded

Question 53

GFP expressed in – cells to show loading and unloading

Answer 53

companion cells