Question

Write the function of

a. Sieve tube

b. Interfascicular cambium

c. Collenchyma

d. Aerenchyma

Answer 1

Sieve tubes: structure

• Sieve tubes are long, tube-like structures, arranged longitudinally and are associated with the companion cells.
• Their end walls are perforated in a sieve-like manner to form the sieve plates.

Sieve tubes: Function

• Sieve tube are involved in the translocation of food from the leaves to the other parts of the plant body and vice versa.

Interfascicular cambium

• At the time of secondary growth, cells of medullary rays (strips of parenchyma separating xylem and phloem bundles) become meristematic to form interfascicular cambium.

Function

• Interfascicular cambium helps in the secondary growth of dicot stem by inducing the formation of secondary xylem and secondary phloem.

Collenchyma structure

• Collenchyma is found either as a homogeneous layer or in patches. It consists of cells which are much thickened at the corners due to a deposition of cellulose, hemicellulose and pectin.
• Collenchymatous cells may be oval, spherical or polygonal and often contain chloroplasts.

Function

• Collenchyma provides mechanical support to the growing parts of the plant such as the young stem and petiole of a leaf.

Aerenchyma tissue structure

• Aerenchyma is a type of parenchyma tissue which has air spaces in them.

Function

• Due to the presence of air in between the tissue, aerenchyma provides buoyancy to aquatic plants and helps them to float.