MCQs on Plant Anatomy with Explanation

Ans. (d) Bast Fibres

Explanation: Bast Fibre (also called phloem fibre or skin fibre) is a type of plant fibre received from the phloem (also known as "inner bark" or "skin") or bast encircling the dicotyledonous plants' stems. They offer hardiness to the branch and support the phloem's conducting cells.

Ans. (d) Phellogen

Explanation: Epidermis and pericycle cells with parenchyma or collenchyma cells develop the secondary meristematic property and are changed to phellogen or cork cambium during extrasolar secondary growth.

Ans. (a) Suberin

Explanation: After the leaf falls, the scar is exposed to air, forming a first protective layer on the scar's wall through the deposition of lignin and suberin. Suberin is a waxy chemical found in the thicker cell walls of many trees and plants, notably in cork tissues, and is comparable to cutin. The outer cork cambium eventually loses protoplast and dies, resulting in the suberization of the cell walls. Suberin deposition (suberization) creates a water-resistant layer.

Ans. (c) Primary Growth

Explanation: Primary growth is the consequence of the intercalary meristem. Many monocots benefit from intercalary meristems because they are capable of cell division and fast growth and renewal. Bamboo's intercalary meristems allow fast stem elongation. The bases of many grass leaf blades aid injured leaves to heal quickly. This leaf regeneration in grasses evolved due to grazing herbivore damage but is most commonly associated with lawnmowers.

Ans. (b) Vessel

Explanation: Vessel is a more sophisticated type of tracheary element. They have perforation plates on the end walls and are shorter than tracheids. Individual vessel sections are connected end to end in vertical rows to form vessels; each vessel is a continuous tube with little or no obstacle to water flow, depending on the size and kind of perforated plates in the end walls.

Ans. (c) Collenchyma

Explanation: Collenchyma cells are permanent tissue that gives structure and stability. Their thick cell walls are made up of cellulose and pectin molecules. Lignin isn't found in collenchyma. It's a supportive tissue made up of live cells with thicker main walls that are not lignified.

Ans. (d) The number of yearly rings is counted.

Explanation: Counting the yearly rings of wood growth is the most precise approach to calculate a tree's age. There usually are two techniques for counting annual rings. An increment borer can harvest an increment core from a tree.

Ans. (d) Endogenous

Explanation: The mature pericycle of the parent root gives rise to lateral root primordia. A periclinal division, which produces a double layer of pericycle-derived cells, is one of the initial occurrences. As shown by differential gene expression in the inner and outer layers, primordia cells differentiate nearly soon after commencement. An endogenous lateral branch emerges from the pericycle and goes through the cortex.

Ans. (b) Vessel wall

Explanation: Bordered pits are holes in the lignified cell walls of xylem conduits (vessels and tracheids) that are crucial components in the water-transport system of higher plants. They are abundantly found in vessels of angiosperms and tracheids of gymnosperms and ferns.

Ans. (b) Cells that are elongated and have thickened edges

Explanation: Collenchyma is a fundamental permanent tissue that primarily serves to sustain a plant's shoot system mechanically. Cells can sometimes contain tiny intercellular gaps. The collenchyma cells look polygonal, round, or oval in a slice. The existence of a cell wall that is irregularly thick distinguishes the cells.

Ans. (b) Four

Explanation: The two-dicot root vascular bundles are the radial and tetrarch root vascular bundles. There are four alternating xylem and phloem bundles in total. Monocot roots' vascular bundles are organized in a radial arrangement. There are eight bundles in each xylem vessel and phloem vessels bundle. Polyarchy is the term for the situation as a result of this. The vascular bundles in the stems of dicots are eight in number and organized in the shape of a broken ring. There are basically three types of vascular bundles namely conjoint, collateral, and open. The inner surface has xylem, and the outer surface has a phloem. The three-monocot stem vascular bundles are conjoint, collateral, and closed stem vascular bundles. A centrifugal pattern is formed by several vascular bundles that are irregularly scattered and organized.

Ans. (d) Endodermis

Explanation: Casparian strip is a band of cell wall layers formed on the endodermis's radial and transverse walls chemically different from the remainder of the cell wall. The Casparian strip produces suberin and lignin on rare occasions, while the cell wall is lignin-based and lacks suberin. It restricts the passive flow of elements, including water and solutes, into a plant's stele.

Ans. (a) Lateral meristem

Explanation: Secondary growth in plants is caused by cell division in the lateral meristems or secondary meristems, which increases the thickness or girth of the plant. The cork cambium and the vascular cambium are the two lateral meristems that create secondary growth in vascular plants. In woody plants, secondary development produces wood and thickens the trunk.

Ans. (d) All the roots

Explanation: A meristem is a tissue in most plants that comprises undifferentiated cells (meristematic cells) found in areas where growth is possible. Meristematic cells give birth to the plant's many organs and keep growing. The root apical meristem (RAM) generates meristematic cells that enable future root development, while the shoot apical meristem (SAM) generates organs like leaves and flowers. The apical root meristem grows cells in two dimensions, unlike the shoot apical meristem. It has two pools of stem cells that form the bulk of the cells in an adult root and are arranged around an organizing centre called the quiescent centre (QC) cells. The apical meristem of the root may be present in all roots.

Ans. (b) Epidermis and cork

Explanation: The epidermis serves as the plant's protective layer in the primary stage. It forms the outer covering, but as secondary growth progress and the tree's girth increases, the outer cortical and epidermis begin to break down, and another meristematic tissue called cork cambium or phellogen develops the inner side. Phelloderm grows on the outside, forming periderm.

Ans. (d) All of these

Explanation: The lengthy tracheary segments that convey water are the most characteristic xylem cells. The morphology of tracheids and vessel elements differs; vessel elements are shorter and are linked together to form long tubes known as vessels. Parenchyma and fibres are two more cell types seen in the xylem.