Results from a ringing experiment with radioactive carbon dioxide Flashcards
An experiment was carried out in which different plants were ringed at different locations on the stem
The plants were then supplied with radioactive carbon dioxide (14CO2)
After a period of time the levels of radioactive carbon in the different parts of the plant were measured
There is a control plant used in this experiment to illustrate where
sucrose is translocated when a plant is intact
The results from the experiment show that:The results from the experiment show that:
The phloem is involved in the transport of sucrose
There is no radioactive sucrose detected past the ringing point on the stems (where the phloem has been removed)
In the phloem the transport of sucrose occurs both upwards and downwards
Sucrose is translocated from the source tissues in the leaves to the sink tissues above and below
Radioactive tracers can also be used to show where substances are transported using autoradiographs!After a plant has taken up radioactive carbon dioxide and carried out photosynthesis and translocation, it is pressed against photographic paper (in the dark) for several hours. The radioactive material present in the plant tissues creates an image to show here it is present.
