Question
Question: Passage cells help in the A. Transport of water towards Pericycle B. Transport of water towards...
Passage cells help in the
A. Transport of water towards Pericycle
B. Transport of water towards epiblema
C. Absorption of water from soil
D. Passage of carbon dioxide towards stomata
Solution
Pericycle is the outermost portion of stele. It is a cylindrical thin walled parenchymatous or thick walled sclerenchymatous tissue. It is single layered or multilayered. Pericycles may be present in the form of patches.
Complete answer:
Passage cells help in the transport of water towards the Pericycle. Passage cells are found in the endodermis and exodermis layer of the roots of the plants. Passage cells help in the transfer of water and mineral salts from the cortex into the xylem. These are modified endodermal cells which allow the transport of water. These cells have thin walls and there is no deposition of suberin. Passage cells also allow transfer of solutes such as calcium and magnesium into the stele. Exodermal passage cells have a cytoplasmic structure which plays a role in the ion uptake.
Pericycle is found in the monocot root (gives rise to vascular cambium and cork cambium) and dicot root (only lateral roots) and it is also found in the monocot stem (absent) and dicot stem (parenchymatous or sclerenchymatous cells). Passage cells are also known as transfusion cells.
Functions of the Pericycle:
Thick-walled Pericycle gives mechanical support to the plants.
Pericycle acts as a storage organ of food materials when it is composed of parenchymatous cells.
In dicot roots, the Pericycle becomes meristematic and forms a part of the cambial ring. This cambial ring gives rise to the secondary tissues.
Pericycle gives rise to the lateral roots.
In dicot roots, the Pericycle strengthens the roots and provides protection for the vascular bundles.
**So the correct answer is option A.
Note: Pericycle is the tissue which belongs to the ground tissue system. It is also known as a fundamental tissue system. This tissue system consists of cortex (lies below the epidermis), Pericycle and pith (also known as medulla).