A variegated leaf with green and white areas is left in bright light and then tested with iodine. What does the test show in the white areas, and why?

Explanation

Cells with no green pigment cannot capture light energy, so they carry out no photosynthesis and lay down nothing for the iodine to stain. Sugar does travel through a leaf, but it moves towards the cells that need it and is spent there, so a white area is a place that draws sugar in and uses it rather than a place with a surplus to bank as a store; shading is not the explanation either, since the white areas received exactly as much light as the green ones.