Name: Theories for Ascent of Sap
Uploaded: 2019-07-19
Duration: 5 min 10 s
Description: It's a gravity-defying stunt that the sap pulls off! How do water and minerals travel upwards from the root via the xylem? Learn the theories that explain th...

Question

A student observes a transverse section through a plant stem under a light microscope. The student draws a diagram of the transverse section as shown here.
a) Draw lines on the diagram to label phloem and xylem.
b) Describe the function of phloem and xylem plant tissues.
c) Explain the process of transpiration. How is transpiration involved in the movement of water in the plant?

Accepted Answer

a)

A transverse section of a plant stem showing vascular bundles.
b) The vascular tissue in the plants helps in the transport of water and solute particles that are synthesised in the leaves of a plant. Xylem helps in the transport of water from the roots to other parts of the body while phloem helps in the transport of solute particles from the leaves to all the parts of the body. Xylem transports water unidirectionally while phloem transports food substances bidirectionally.

c) The loss of water in the form of water vapour from the aerial parts of the plant through the stomata is called transpiration. The loss of water causes a suction pull which forces the water from the root cells into the xylem vessels which then transports water to all the parts of the plant. The water rises up as a result of the suction pull along with the dissolved minerals. This movement is called ascent of sap.

Important Questions on Transportation in Plants and Animals

White blood cells (WBC): &nbsp;These cells fight against the foreign substances that may have entered the body by the process of phagocytosis. It also produces proteins against specific germs that kill them.&nbsp;
Platelets: &nbsp;Platelets are cell fragments that do not possess nuclei. They help in the clotting of blood to prevent excess loss of blood.&nbsp;

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