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How does water is absorbed by the roots ? Discuss different pathways for its translocation.
Answer
Absorption of water : The water is absorbed mainly by diffusion. 

The root hair absorb water a

Transportation : Once water is absorbed it is translocated into deeper layers of root by different pathways as :

(i) Apoplast pathway (ii) Symplast pathway 

(i) Apoplast pathway : It is the pathway which occurs through cell walls. It is non living pathway.

The apoplastic pathway is continuous through walls as well as through intercellular spaces. It does not involve crossing of cell membrane. It does not provide any barrier. Mass flow of water through apoplastic pathway is mainly due to cohesive and adhesive forces.

The casparian strips of endodermis provide check to apoplastic pathway and water has to cross the cell membrane and pass through cytoplasm. The pathway becomes symplast.

(ii) Symplast Pathway : It occurs through interconnected protoplasts. The protoplasts of adjacent cells are connected via plasmodesmata.

The symplastic pathway is slow because of cell membranes and their organelles Symplastic movement may be aided by streaming movement of cytoplasm as in leaf of Hydrilla.

(iii) Vacuolar symplast pathway :  It is the movement of water in the xylem vessels. 

 

How does water is absorbed by the roots ? Discuss different pathways for its translocation.

Three pathways of water movement inside the root.