lants have the potentiality to ABSORB water through their entire surface right from root, stem, leaves, flowers, etc. However, as water is available mostly in the soil, only the underground root system is specialized to absorb water. Roots are often extensive and grow rapidly in the soil.   ADVERTISEMENTS: In roots, the most efficient REGION of water absorption is the root hair zone. Each root hair zone has thousands of root hairs. Root hairs are specialized for water absorption. They are tubular outgrowths of 50-1500 μm (0.05-1.5 mm) length and 10 nm in breadth.  Each root hair has a central vacuole filled with osmotically active cell sap and a peripheral cytoplasm. The wall is thin and permeable with pectic SUBSTANCES in the outer layer and cellulose on the inner layer. Root hairs pass into capillary micropores, get cemented to soil particles by pectic compounds and absorb capillary water.  Pathways of Water Movements in Roots:  There are two pathways of water passage from root hairs to xylem inside the root, apoplast and symplast.    (i) Apoplast Pathway: Here water passes from root hair to xylem through the walls of intervening cells without crossing any membrane or cytoplasm. The pathway provides the least RESISTANCE to movement of water. However, it is interrupted by the presence of impermeable lignosuberin casparian strips in the walls of endodermal cells.  (ii) Symplast Pathway: Water passes from cell to cell through their protoplasm. It does not enter cell vacuoles. The cytoplasms of the adjacent cells are connected through bridges called plasmodesmata. For entering into symplast, water has to pass through plasmalemma (cell membrane) at least at one place. It is also called transmembrane pathway. Symplastic movement is aided by cytoplasmic streaming of individual cells. It is, however, slower than apoplastic movements.  Both the pathways are involved in the movement ACROSS the root. Water flows via apoplast in the cortex. It enters the symplast pathway in the endodermis where walls are impervious to flow of water due to the presence of casparian strips.  Here, only plasmodesmata are helpful to allow passage of water into pericycle from where it enters the xylem. Mineral nutrients also have the same pathway as that of water. However, their absorption and passage into symplast mostly occurs through active absorption. Once inside the xylem, the movement is purely along the pressure gradient. Explanation: