Questions & Answers

Path of water movement from soil to xylem is :
(a) $Metaxylem \rightarrow Protoxylem \rightarrow Cortex \rightarrow Soil \rightarrow Root \ hair$
(b) $Cortex \rightarrow Root \ hair \rightarrow Endodermis \rightarrow Pericycle -\rightarrow Protoxylem \rightarrow Metaxylem$
(c) $Soil \rightarrow Root \ hair \rightarrow Cortex \rightarrow Endodermis \rightarrow Pericycle \rightarrow Protoxylem \rightarrow Metaxylem$
(d) $Pericycle \rightarrow Soil \rightarrow Root \ hair \rightarrow Cortex \rightarrow Endodermis \rightarrow Protoxylem \rightarrow Metaxylem$

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Hint: Water is very important for the growth of plants and other metabolic activities. The water present in the soil is absorbed by the plant either actively or passively. Root \ hairs absorb water and then it is transported to the xylem.

Complete answer:
The absorption of water and minerals is the function of root hairs that are present in millions at the tips of the roots. These are extensions of root epidermal cells that greatly increase the surface area for absorption. Water is absorbed by the root hairs purely by diffusion.
After absorption of water through root hair, it enters the cortex. From the cortex, the water enters the endodermis. The endodermis has Casparian strips. The water molecules are unable to penetrate into this layer so they are directed to wall regions.
The water now enters the pericycle. From the pericycle, the water enters into the protoxylem and then finally into the metaxylem.

Additional information: The water absorbed by the root hairs can move into the xylem elements through two pathways:- Symplast and Apoplast.
The Symplast pathway is the system of interconnected protoplasts. The neighboring cells are connected through cytoplasmic strands that extend through plasmodesmata. The water travels through the cells, their cytoplasm; intercellular movement is through the plasmodesmata.
The apoplast pathway is the system of adjacent cell walls that is continuous throughout the plant, except at the Casparian strips of the endodermis in the roots. The movement of water occurs exclusively through the intercellular spaces and walls of the cells.
So,the correct answer is ‘$Soil \rightarrow Root \ hair \rightarrow Cortex \rightarrow Endodermis \rightarrow Pericycle \rightarrow Protoxylem \rightarrow Metaxylem$’.

Note: The water from the pericycle always flows from protoxylem to metaxylem. It never flows from metaxylem to protoxylem.