From what cell organelle does the desmotubule appear to be derived?

The correct answer will be - endoplasmic reticulum

Explanation:

Plasmodesmata are the cytoplasmic bridges spanning in the cell walls of the plant cell which link the cytoplasm of the adjacent cells. The plasmodesmata play an important role in the plants as they allow the inter-cellular connections between the cells.

The plasmodesmata are derived from the juxtaposed endoplasmic reticulum which forms the axial or the central portion of the plasmodesmata and allows the transport of molecules between two cells.

Thus, the endoplasmic reticulum is the correct answer.