Answer
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Work Step by Step
To confirm that a companion cell communicates with its sieve-tube member using an electron microscope, we could use a technique called freeze-fracture replica immunolabeling (FRIL). This technique involves freezing a sample and fracturing it to reveal the internal structures, and then labeling the structures with antibodies that specifically bind to the proteins of interest.
To apply FRIL to study the communication between companion cells and sieve-tube members, we could prepare a sample of plant tissue that includes both cell types and freeze-fracture it. The fractured surface of the sample would reveal the plasma membrane and associated structures, including plasmodesmata, which are channels that connect the two cells.
Next, we would label the sample with antibodies that recognize a specific protein or molecule known to be involved in cell communication, such as a protein that forms a channel through the plasmodesmata. We could then use electron microscopy to visualize the location of the labeled proteins within the cells and their distribution across the plasmodesmata.
If the labeled protein is present at the interface between the companion cell and sieve-tube member, and is concentrated in the plasmodesmata, it would suggest that the two cells are communicating with each other. Additionally, we could use a combination of FRIL and other electron microscopy techniques, such as serial sectioning or tomography, to obtain a 3D view of the plasmodesmata and confirm that they are connecting the two cells.
