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Phloem

28 flashcardsby Logan
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1
What does phloem tissue transport?
Solutes like sugars and amino acids
2
What are solutes transported in plants called?
Assimilates
3
What type of cells does phloem contain?
Sieve tubes and companion cells
4
What are sieve tubes specialized for?
Transporting solutes
5
What connects sieve tube elements?
Sieve plates
6
What supports sieve tube elements?
Companion cells
7
What do companion cells provide?
Energy for active transport of solutes
8
What is the movement of solutes in plants called?
Translocation
9
What type of process is translocation?
Energy-requiring process
10
From where do solutes move in translocation?
Source to sink
11
What is a 'source' in translocation?
Where solutes are made
12
What is a 'sink' in translocation?
Where solutes are used
13
What maintains the concentration gradient in translocation?
Active loading of solutes into sieve tubes
14
What is the mass flow hypothesis?
Model explaining source-to-sink movement
15
What increases pressure at the source?
Active loading of solutes into phloem
16
What decreases pressure at the sink?
Removal of solutes from phloem
17
What creates a pressure gradient?
Source has high pressure, sink has low
18
What type of tracer can demonstrate translocation?
Radioactive tracers
19
What does supplying a plant with radioactive CO₂ do?
Incorporates into sugars via photosynthesis
20
Where does radioactive sugar travel in a plant?
From source to sink
21
What supports evidence for mass flow hypothesis?
Stopping translocation stops radioactive tracers
22
What would happen if the phloem is punctured?
Sap flows out, showing pressure
23
How is pressure gradient in phloem maintained?
By active loading and unloading of solutes
24
What substance is used in translocation experiments?
Radioactive CO₂
25
What does autoradiography do in translocation experiments?
Locates radioactive substances in plants
26
What is a key feature of the mass flow hypothesis?
Pressure difference drives solute movement
27
What powers active transport in translocation?
ATP
28
What happens if ATP production is inhibited?
Translocation stops
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