Question

Lenticels are patches of
A. Loose cells in leaves
B. Loose cells on bark for aeration
C. Subsidiary cells of stomata
D. Cells for respiration of epiphytes

Answer 1

Hint: Lenticels are the large sized, aerating pores present in the cork tissue known as lenticels. They are found in old dicotyledonous stems or dicot stems. They are formed in the place of stomata. Lenticels help in exchange of gases between the tissues.

Complete answer:
A lenticel is a porous tissue consisting of cells which are having large intercellular spaces in the periderm and the bark of woody stems and roots of dicot flowering plants.
It functions as a pore which provides a pathway for the direct exchange of gases between the internal tissues and atmosphere through the bark.
The name lenticels derives from its lenticular (lens-like) shape.
The shape of lenticels is one of the characteristic features which are used for the identification of trees.
They are mainly found in the old dicotyledonous stem or dicot stem.
They are formed in the place of stomata.
They have outer raised margins and loosely arranged colorless parenchymal cells are present known as complementary cells that are meant for gaseous exchange.
Lenticel formation usually begins beneath stomata complexes during primary growth during the development of the first periderm.
The formation of lenticels seems to be directly related to the growth and strength of the shoot and on the hydrose of the tissue, which refers to the internal moisture.
As stems and roots mature, lenticel development continues in the new periderm.

So, the correct option is option b. loose cells on bark for aeration.

Note: The growth of the roots and stem in length with the help of apical meristem is called primary growth.
Apart from primary growth most dicot plants exhibit an increase in girth. This increase is known as secondary growth.
The tissues involved in secondary growth are:
1. Vascular cambium
2. Cork cambium