Question

What role does root pressure play in water movement in plants?

Answer 1

Roots are the organs of the plants that helps in uptake of water along with the nutrients into the plant body. These are modified structures of the plant body which are present under the soil and help in uptake of nutrients present in the soil for overall growth and development of the plants.

Complete answer:
Root growth is an important function of the apical meristem which is located near the tip of the root. The meristem cells present in the body of the plants divide continuously which produces more meristem cells, root cap cells and undifferentiated root cells. These root cells differentiate and modify to perform various functions like providing water, nutrients and support to the plants which help in overall growth of the plants.
The pressure exerted by the roots is a positive pressure that is developed by active absorption of the nutrients from the soil. Nutrients present in the soils are actively absorbed with the help of root hairs along with increase in pressure in xylem by the water along with other minerals. This pressure leads to upward movement of the water to small heights. The root pressure can be observed by cutting of watered plant on a humid day as when the stem is cut, the water oozes from the cut end. Root pressure helps the water to transport to a small height and then it re-establishes the continuous chain of water molecules in the xylem. Transpirational pull facilitates the flow of water molecules from roots to the shoots.

Note: The force of gravity directs roots to grow downward at the time of germination, the mechanism of growth helps the plant which causes shoots to grow upward.