Question

Tunica corpus theory is related to
a. Root apex
b. Lateral meristem
c. Root cap
d. Shoot apex (apical meristem)

Answer 1

Hint: The meristem is a type of tissue found in plants. It mainly consists of undifferentiated cells (meristematic cells) capable of cell division. The cells present in the meristem can develop into all the other tissues and organs that occur in plants.

Complete answer:
The concept of the organization and the development of the apical meristem, into which the meristematic region is divided into an outer peripheral layer or layers, called the tunica, and an inner mass of cells, called the corpus.

 The theory of the Tunica corpus was given by Schmidt. In the following theory, it is said that the shoot apex of the angiosperms has two distinct zones. Peripheral zone that is present is called tunica and the central zone is called corpus. The tunica divides only in anticlinal planes and the corpus divides in various planes.

Hence, the correct answer is option (D).

Additional information:
 Following points that are highlighted are the top three theories of shoot apical meristem. The main theories are:
• The Apical Cell Theory: Nageli in 1944 advocated this theory. In the theory it states that a single apical cell interprets the structural and functional unit of apical meristem. In this the cell is shaped like an inverted pyramid and it is large.

• The Histogen Theory: the scientist Hanstein put forward this paper in 1868 and he says according to the theory the tissues of a plant body originate in the form of a mass meristem where the histogen dermatogen, periblem, plerome are distinguished.

• Tunica-Corpus Theory: The epidermal and the sub epidermal layers together form the tunica. The inner layer is called the corpus which is the L3 layer. This layer is arranged in a random fashion compared to the other layers of the meristem.

Note: The ability of the non-differentiated meristematic cells includes totipotent and continuous cell division. The theory of tunica corpus is associated with the two zones tunica i.e. peripheral one and the other corpus which is the central zone.