Answer: zero.
- A zero
- B positive
- C highly negative
- D infinitely large
Correct answer: A. zero
Explanation: By convention, pure water has a water potential of zero.
Water can travel through cell walls (apoplast) or cell-to-cell through the cytoplasm (symplast) - but the Casparian strip at the endodermis blocks the apoplast route entirely, forcing everything through a selectively permeable membrane (symplast) before it can enter the xylem.
Concept context
Water and mineral absorption, the ascent of sap, transpiration, and phloem transport via the pressure flow hypothesis.