Question

Choose the incorrect statement.
a. Permanent tissues have all cells similar in structure and function are called simple tissue.
b. Complex tissue has different types of cells performing different functions altogether.
c. Secondary meristem is a lateral meristem.
d. The cells of permanent tissues divide further.

Answer 1

Hint: A tissue is a cluster or group of cells that perform a specific function. Based on the capacity of cell division, the plant cells are divided into two groups – permanent tissue and the meristematic tissue. This question can be easily answered by knowing the definition and the types of these tissues.

Complete answer:
> Permanent tissues:
They are the tissues that have undergone differentiation and have lost the ability to divide further or differentiate. They contain both live and dead cells with or without nuclei. They are usually large and further divided into two types namely:
Simple permanent tissue: They contain single or the same type of cells which are similar in their origin, structure and function. The examples are parenchyma, collenchyma and sclerenchyma cells.

> Complex permanent tissue:
They are made up of various types of cells that carry out different functions. Examples are xylem and phloem tissues. Xylem tissues contain tracheids, vessels, fibres and parenchyma. Phloem contains sieve tubes, parenchyma, fibres and companion cells.

> Meristematic tissues:
They are the type of tissues that have the ability to differentiate into other types of cells when they grow and divide. They always contain living cells with large nuclei and dense protoplasm.
On the basis of origin, it is divided into promeristem (youngest), primary meristem (arises from promeristem) and secondary meristem (arises from secondary meristem).

On the basis of position, it is divided into:
• Apical meristem: Present at root tip and shoot tip. Helps in increasing height.
• Intercalary Meristem: Present at the intercalary position in the leaves and internodes. As a part of apical meristem, it adds to the height of the plant.
• Lateral Meristem: Present in the stems and roots on the lateral side. It helps in increasing the thickness of the plant. The examples for lateral meristems are vascular cambium and cork cambium.

Hence, the correct answer is option (D).

Additional information:
Apart from the tissues mentioned above, there are other specialised tissues in plants that carry out secretory functions. They are laticiferous tissues and glandular tissues. The laticiferous plant tissues are elongated secretory cells that contain and secrete latex in some plants. The glandular tissues contain cells that secrete oil, tannin, mucilage, gum, resin, poison etc.

Note: Some of the permanent cells in plants are dead and these cells are mainly involved in providing mechanical support to the plant. The main reason for the plants to use dead cells is because the dead cells do not require any maintenance constantly like the living cells. The cell walls of these cells contain materials such as lignin that helps in providing support to the plant performing the functions of a skeleton.