How can the translocation of solutes in plants be modelled in an experimen?
using radioactive tracers
STEP 1?
Supply a part of a plant (often leaf) with an organic substance that has a radioactive label (eg CO2 containing the radioactive isotope 14C)
This radioactively-labelled CO2 can be supplied to a single leaf by being pumped into a container completely surrounding the leaf
STEP 2?
radioactive carbon will then be incorporated into organic substances produced by the leaf (eg sugars from photosynthesis) which will be moved around the plant by translocation
STEP 3?
movement of these organic substances tracked using AUTORADIOGRAPHY
To reveal where the radioactive tracer has spread to in a plant, the plant is killed (eg frozen using liquid nitrogen) and then whole plant/sections is placed on PHOTOGRAPHIC FILM
the radioactive substance present whereever the film turns black
what do the results demonstrate?
The translocation of substances from source to sink over time
what does photosyntesis do?
Produces glucose
This is transported to SUCROSE for transport around the plant
