Question

Water will move from the root hair through cortex if the water potentials are _________________________.

• A. Root hair- $0$, Cortex-$0$, Xylem-$0$
• B. Root hair-$-2$, Cortex-$-1$, Xylem-$0$
• C. Root hair-$0$, Cortex-$-1$, Xylem-$-2$
• D. Root hair-$0$, Cortex-$+1$, Xylem-$+2$

Answer 1

Answer: (C)

Root hair-$0$, Cortex-$-1$, Xylem-$-2$

If a difference in water potential exists between the two regions, spontaneous movement of water will take place, provided the movement can occur between them. The direction of flow will be energetically down hill, that is from the region of higher water potential(root hair) to the region of lower water potential(xylem) via cortex from less negative water potential (e.g., - $1$ kPa) to more negative water potential (e.g., - $2$ kPa).

So, the correct answer is 'Root hair-0,, Cortex-−1, Xylem−2'