Fig 6. Differential growth analysis and model.

A, Diagram plotting the relative extension of the hypocotyl (y-axis; length of the hypocotyl in WL+FR divided by the length in WL conditions) against the relative changes in TE cell number (x-axis; number of TE cells in WL+FR divided by the number of TE cells in WL conditions) including the added standard errors. B, Our model proposes that downstream of the perception of shade, a vascular patterning module operates to induce trans-differentiation of TE cells without new cell divisions. The increase in TE numbers is required to maintain constant vascular density in the hypocotyl during elongation. It is however possible that the auxin produced in response to phytochrome signaling impinges on the vascular patterning module and contributes to the increase in TE numbers.