Question

Which of the given statement(s) is/are correct?
A. The apoplastic movement of water occurs exclusively through intercellular spaces and walls of the cell.
B. The symplastic system is of interconnected protoplasts.
C. The symplast does not provide any barrier to water movement.

• A. A and B
• B. Only B
• C. B and C
• D. A, B, and C

Answer 1

Answer: (A)

Plant growth depends on its ability to take up water and dissolved minerals from the soil. The root system of every plant is equipped with the necessary tissues to facilitate the entry of water and solutes. The plant tissues involved in the transport of water and minerals have two major compartments - the apoplast and the symplast.
The apoplast includes everything outside the plasma membrane of living cells like cell walls, extracellular spaces, xylem, phloem, and tracheids. The symplast, in contrast, consists of the entire cytosol of all living plant cells and the plasmodesmata.
The absorbed water from the root hair moves towards the xylem, which helps in the ascent of sap. According to Munch, 1930, there are mainly two paths:
1. The apoplast is a type of or path of movement of water molecules absorbed by the root hairs. In this way, water passes from the root hairs to xylem through the non-living path or via the walls of the intervening cells without crossing any membrane or cytoplasm.
2. In the symplast path, the water molecule moves from one cell to the other through their protoplasm and by crossing their plasmodesmata. This path is called the Transmembrane pathway.
Due to the movement of water through protoplasm of the cells, metabolic states interfere with the flow of water in the symplastic pathway. Even the presence of Casparian strips in the endodermis, force the water to move through the cytoplasm, creating more resistance. On the contrary, the apoplastic pathway is fast.