Back to Biology
Biology · Plant transport · Xylem
Tracking water flow through xylem
A celery stalk is placed in red food dye. Over an hour, the dye travels up the stalk. Cutting a cross-section reveals which tissue carried the water — the dye traces out the xylem vessels.
t = 0 min
Observation
Red dye rises through narrow channels in the celery stalk, eventually reaching the leaves. Cutting horizontally reveals discrete red dots arranged in a ring — the xylem vessels (vascular bundles).
Exam-style questions
1. Why does the dye rise UP the celery stalk?
2. In the cross-section, the red dye appears in distinct strands. Which tissue?
3. Why is XYLEM made up of DEAD, hollow, lignified cells?
4. If celery is left longer, dye reaches the leaves. Function of xylem?