Test: Plant Tissues - Class 9 MCQ

The term tissue was given by marie francois xavier bichat in the year 1792. he was a french anatomist and pathologist and he was also know as 'father of histology '

It is because that in eukaryotes the erticular tissue used to do one function...so they follow division of labour.

Sclerenchyma

Sclerenchyma is composed of dead cells. They provide mechanical support.

Pear flesh is infused with very fine grit, made of clusters of stone cells. Stone cells, a subtype of sclereid cells, make up some other very hard tissues like peach pits and nut shells. Stone cells are born with their own death as an end goal. They begin as all other plant cells do, with thin primary walls.

Complete answer: The sclerenchyma is mainly composed of the dead cells which provide the strength and rigidity to the stem. It also provides a protective covering to the nuts and fruits as the cell walls consist of a high proportion of lignin and cellulose.

The pair of kidney-shaped cells present around stomata are called guard cells.
Explanation:
- The stomata are small openings present on the surface of leaves and stems that allow for gas exchange.
- The guard cells are specialized cells that surround each stoma and control its opening and closing.
- The shape of the guard cells is kidney-shaped, with a bulge on one side and a concave on the other side.
- The inner side of the guard cells facing the stomatal pore is thicker and more rigid, while the outer side is thinner and flexible.
- When the guard cells take up water, they become turgid and swell, causing the stomatal pore to open.
- Conversely, when the guard cells lose water, they become flaccid and shrink, leading to the closure of the stomatal pore.
- The opening and closing of stomata by the guard cells regulate the exchange of gases, including carbon dioxide and oxygen, as well as the loss of water through transpiration.
- Guard cells also play a role in controlling the entry of pathogens and regulating the plant's response to environmental factors such as light, temperature, and humidity.

The epiblema is the outermost epidermal layer of the root. The root hair cells are unbranched and lack cutinisation. They are responsible for absorbing water from the soil. The stem also possesses hairs but they are mostly multicellular. 

The tracheary elements of the xylem are the tracheids and the xylem vessels. A tracheid is a tubular cell whose primary function is to conduct water and mineral salts, provide structural support, and prevent air embolism in vascular plants. A xylem vessel is a series of cells arranged in a way that enables rapid and more efficient water and mineral conduction in most angiosperms. 

The incorrect sentence is “apical and intercalary meristems are permanent tissues”. The rest a, b and d are correct sentences.

Apical and intercalary tissues are meristematic tissues and not permanent tissues. Apical tissues are present on the tips of root and stem, they increase the length; intercalary tissues are present in the internodes, they increase the length between the nodes.

Conduction of water and minerals in plants takes place in conducting vessels, located in the core, called Xylem. Thus conduction of water is not the function of the epidermis but Xylem.

Apical meristem also known as growing tip , is an undifferentiated meristematic tissue found in the buds and growing tips of roots in plants . Its main function is to trigger the growth of new cells in young seedlings at the tip of roots and shoots and forming buds .

Cork cambium is a tissue found in many vascular plants as a part of the epidermis. It is one of the many layers of bark, between the cork and primary phloem. The cork cambium is a lateral meristem and is responsible for secondary growth that replaces the epidermis in roots and stems.

The intercalary meristem of the meristems present at the base of the internodes stem or leaf.
It helps in the elongation and growth of the plants at the nodes and internodes ( stems and leaves) and also enables the longitudinal growth of the stem and leaves (grasses).
 

Parenchyma cells are plant cells that have thin cell walls and are usually involved in storage, photosynthesis, and support. Sclerenchyma cells are plant cells that have thick cell walls and are usually involved in support and protection.

Collenchyma cells are plant cells that have thickened cell walls at the corners and are usually involved in support. These cells are found in areas of the plant that are undergoing growth or where there is a need for extra support, such as at the tips of shoots and stems and in the outer layers of leaves.

Therefore, the correct answer is 1, "Collenchyma."

Nucleus is not present in:
- Companion cell: Companion cells are specialized parenchyma cells that are closely associated with sieve tube elements in the phloem tissue. They play a crucial role in supporting the functions of sieve tube elements by providing them with metabolic support. Companion cells have a nucleus present in them.
- Mature sieve tube: Sieve tube elements are elongated cells that form the conducting tubes of the phloem tissue. They are responsible for the transport of sugars and other organic substances throughout the plant. However, mature sieve tube elements lack a nucleus. They lose their nucleus during their development to make more space available for the transport of nutrients.
- Phloem parenchyma: Phloem parenchyma cells are living cells that are involved in various metabolic functions within the phloem tissue. They provide support, storage, and repair functions. Similar to companion cells, phloem parenchyma cells possess a nucleus.
- Collenchyma: Collenchyma is a type of ground tissue that provides mechanical support to growing plant parts. It contains living cells with thickened cell walls. Collenchyma cells also have a nucleus present in them.
Therefore, the correct answer is b. Mature sieve tube, as they do not have a nucleus.

PHLOEM :- The structural elements of phloem include sieve tubes, companion cells, Phloem parenchyma and secretory cells. The sieve tube is the conducting element of the phloem. It is formed from a vertical series of elongated cells, interconnected by perforations in their walls in areas known as sieve plates.

Sclerenchyma is a type of permanent tissue. They are dead, elongated, thin, narrow cells with thickened walls without any internal space. Therefore, option C is correct.

Laticiferous tissues are made up of thin walled, elongated, branched and multinucleate (coenocytic) structures that contain colourless, milky or yellow coloured juice called latex. These occur irregularly distributed in the mass of parenchymatous cells.