Question

Symplast and apoplast pathway helps us to understand

• A. movement of sugars through phloem
• B. absorption of water by roots into xylem
• C. both b and c
• D. ascent of sap

Answer 1

The correct option is B absorption of water by roots into xylem

Apoplast and symplast pathway helps us to understand the absorption of water by the roots from the soil.

The water is absorbed by the root in two ways:
1. Apoplast pathway: Here water moves through the cell wall and intercellular spaces of the root. The water does not cross the cell membrane. So, apoplastic movement of water is through the nonliving parts of the plant.

2. Symplast pathway: Here water moves through the cytoplasm of the cell by crossing the cell membrane. Water moves to the neighbouring cells through plasmodesmata. Plasmodesmata are channels that interconnect the neighbouring cells. So, symplastic movement of water is through the living parts of the plant.

Ascent of sap is the upward movement of water from the xylem of roots to the aerial parts of the plant. Root pressure theory and cohesion tension transpiration pull theory helps us to understand the ascent of sap.

Translocation (long distance transport of substances through vascular tissues) of sugars via phloem from source to sink is explained by mass flow or pressure flow hypothesis.