Anatomy of Flowering Plants MCQ

Ans. d) I, II, and III are correct

Explanation: Apical meristems are located at the tips of the shoots and roots, and they are responsible for the elongation and expansion of the plant. This type of meristem is responsible for the continuous growth of the plant and produces cells that will differentiate into leaves, stems, and flowers.

Intercalary meristems, on the other hand, are located at the base of leaves and the nodes of grasses. They are responsible for adding new cells between mature cells and allowing for continued growth in specific regions of the plant. This type of meristem is essential in grasses as it allows them to recover quickly from damage, such as grazing by animals.

Ans. a) They prevent water loss due to transpiration

Explanation: Trichomes can help reduce water loss by providing shade and reducing the surface area exposed to the sun. Trichomes can also regulate temperature by providing insulation and helping to reduce heat stress in hot environments.

Ans. d) protoderm is a vascular tissue of a monocot stem

Explanation: Protoderm is not a vascular tissue of a monocot stem. Protoderm is the initial layer of cells that develops into the epidermis, the outermost layer of cells, in the process of plant growth and differentiation. The epidermis is the protective layer of cells that covers the plant's surface and helps prevent water loss, protect against pathogens, and regulate gas exchange.

Ans. b) Collenchyma

Explanation: The tissue that has an unevenly thick cell wall, has a primary wall (cellulose) and a secondary wall (hemicellulose or pectin) and is a simple, living, primarily mechanical tissue of the plant body is called collenchyma.

Collenchyma is a type of ground tissue that supports the plant and helps prevent wilting by maintaining turgor pressure. It is characterized by unevenly thick cell walls that are composed of cellulose and hemicellulose or pectin. These thick walls give the cells added strength and stiffness, making collenchyma an important tissue for plant support.

Ans. Both I and II are correct

Explanation: Intercalary meristems are not called primary meristems. Intercalary meristems are named as such because they are located in between mature cells, or in an "intercalary" position. They are not called primary meristems because that term is used to refer to the three main types of meristems in plants: apical, lateral, and intercalary.

Primary meristems, including apical and lateral meristems, are the initial tissues from which all plant organs arise. They are composed of undifferentiated cells that can divide and differentiate into a variety of tissue types, including stems, leaves, flowers, and roots.

Ans. d) They provide mechanical strength to the growing parts of the plant.

Explanation: Collenchyma is a type of ground tissue in plants that provides support and helps maintain turgor pressure. Collenchyma cells have unevenly thick walls composed of cellulose and hemicellulose or pectin, which give the cells added strength and stiffness. 

They are typically elongated and arranged in strands or columns to provide mechanical support to the plant. In addition to its support function, collenchyma also plays a role in the transport of water and solutes within the plant, and in some cases, it can act as a storage tissue for food.

Ans. a) Pericycle

Explanation: In dicot roots, the initiation of the lateral roots and the vascular cambium during secondary growth takes place in the pericycle. The pericycle is a layer of cells located just inside the endodermis, which is the innermost layer of the cortex in the roots.

During secondary growth, the pericycle cells divide and differentiate into lateral roots, which emerge from the sides of the primary root, and the vascular cambium, which is a layer of meristematic cells that produces secondary xylem and phloem. These tissues are important for increasing the root's absorptive and transport capabilities, as well as providing additional support to the plant.

Ans. b) Conjoint, open, and with endarch protoxylem.

Explanation: In dicot stems, the vascular bundles are usually arranged in a ring, with the xylem and phloem arranged in an open, circular configuration. The xylem, which is responsible for transporting water and minerals from the roots to the rest of the plant, is formed from endarch protoxylem, meaning that the oldest xylem cells are located towards the centre of the bundle.

The arrangement of the vascular bundle in dicot stems provides for the efficient transport of water, minerals, and nutrients to all parts of the plant, supporting growth and development. 

Conjoint, open, and with exarch protoxylem, is a characteristic of monocot stems, where the xylem cells are formed from exarch protoxylem, meaning that the oldest cells are located towards the periphery of the bundle. Conjoint and closed, is not common in dicots. Option 4, scattered, each surrounded by a sclerenchymatous bundle sheath, is not a characteristic of dicot stems.

Ans. c) Are located in isobilateral leaves and help in minimizing water loss.

Explanation: Bulliform cells are specialized cells found in the mesophyll of dorsiventral leaves, which are leaves with distinct upper and lower surfaces. They are large, thin-walled cells that can change shape in response to water loss, curling, and uncurling to help regulate water balance in the plant. 

When the plant loses water, bulliform cells shrink and cause the leaf to curl, reducing the surface area exposed to the air and minimizing water loss. When the plant is well-watered, bulliform cells expand and cause the leaf to uncurl, allowing for maximum exposure to light for photosynthesis.

Ans. a) Maturation

Explanation: Root hairs are thin, elongated cells that project from the epidermal cells of the root and are involved in the uptake of water and minerals from the soil. They are formed from the cells of the root meristem, which is the zone of actively dividing cells at the root tip. The root meristem produces new cells that differentiate into various tissues, including the root hairs.

Ans. d) Both sieve tubes and companion cells

Explanation: Phloem is the tissue in plants responsible for transporting sugars and other organic compounds from the leaves, where they are produced through photosynthesis, to the rest of the plant. 

In angiosperms, the dominant type of flowering plant, the phloem consists of sieve tubes and companion cells. The sieve tubes are elongated cells with perforated walls that facilitate the transport of sugars, while the companion cells are adjacent cells that regulate the activity of the sieve tubes.

Ans. a) Tracheids

Explanation: In gymnosperms, which are non-flowering plants that include conifers, cycads, and ginkgos, the xylem consists mainly of tracheids. Tracheids are the primary water-conducting cells in gymnosperms, as vessels are absent or rare. 

Tracheids in gymnosperms have unevenly thickened cell walls that provide mechanical support and prevent the stem from collapsing due to the negative pressure created by water transport.