Rajasthan Board RBSE Class 11 Biology Chapter 14 Plant Tissue System
RBSE Class 11 Biology Chapter 14 Multiple Choice Objective Questions
Question 1.
Epidermal tissue system originates from-
(a) Plerome
(b) Dermatogen
(c) Periblem
(d) Calloptrogen
Question 2.
Stomata are found on both epidermal layers in
(a) monocots plants
(b) xerophytes
(c) aquatic plants
(d) plants growing in salts
Question 3.
Casparian strips are formed by
(a) Lignin
(b) pectin
(c) suberin
(d) cellulose
Question 4.
The space between epidermis and Endodermis is called
(a) vascular bundle
(b) cortex system
(c) pleorome system
(d) xylem system
Question 5.
Pith and medullary are made of
(a) Parenchyma
(b) Collenchyma
(c) Xylem
(d) sclerenchyma
Question 6.
The vascular bundle in Xylem and phloem are on different radius.
(a) Radial
(b) Conjoint
(c) Concentric
(d) Bicollateral
Question 7.
Amphivasal vascular bundles are found in.
(a) Dracaena
(b) Pranango
(c) Sunflower
(d) Cucurbitta
Question 8.
Stomata found in mococots plants are
(a) Kidney shaped guard cells
(b) Shape of apple seeds
(c) dumbell shaped guard cells
(d) Sunken stomata
Question 9.
Stomata found in xerophyte plants are
(a) Dumbell shaped
(b) Shape of apple seeds
(c) Exposed type
(d) Sunken stomata
Question 10.
Epidermis does not contain
(a) Stomata
(b) Intercellular spaces
(c)Trichomes
(d) Cuticle
Answers:
1. b, 2. a, 3. c, 4. b, 5. a, 6. a, 7. a, 8. c, 9. d, 10. b
RBSE Class 11 Biology Chapter 14 Very Short Answer Questions
Question 1.
How many type of basic tissue systems is present in the flowering plants. Give the tissue names under each system.
Answer:
The three basic tissue systems are-
- Epidermal (or Tegumentary),
- Fundamental (or Ground tissue)
- Vascular (or Fascicular) systems.
Question 2.
Cuticle is made of which substance
Answer:
Cutin.
Question 3.
Cambium are found in which type of vascular bundles?
Answer:
Open vascular bundle.
Question 4.
Stomatal apparatus consists of which components?
Answer:
(i) The stomatal apparatus consists of a stomatal aperture, two guard cells and surrounding subsidiary cells.
(ii) Trichomes in the short system help in preventing water loss due to transpiration.
Question 5.
Passage cells are found in?
Answer:
opposite sides of protoxylem.
Question 6.
Which vascular bundles are called Conjoint vascular bundles?
Answer:
Conjoint : A vascular bundle having both xylem and phloem together. Normally the xylem and phloem occur in the same radius. They occur in stems.
Question 7.
Which vascular bundles are called Centrifugal vascular bundles?
Answer:
The vascular bundles are formed from centre to periphery (Centrifugal/acropetal).
Endarch: The protoxylem lies towards centre and metaxylem towards periphery.
Question 8.
Which is the first formed Xylem?
Answer:
Protoxylem.
Question 9.
What is starch sheath called as?
Answer:
Endodermis.
RBSE Class 11 Biology Chapter 14 Short Answer Questions
Question 1.
Define Tissue System
Answer:
All the tissues of a plant which perform some general function irrespective of its position in plant body are considered to form together a tissue system.
Question 2.
Bulliform cells are found where and what is their role?
Answer:
Some of the cells in the leaves of grasses are comparatively very large, called bulliform or motor cells. They are thin-walled and contain big central vacuoles filled with water. They play an important role in the folding and unfolding of leaves.
Question 3.
Differentiate between Exarch and Endarch?
Answer:
Exarch: The protoxylem lies towards periphery and metaxylem towards centre.
Endarch: The protoxylem lies towards centre and metaxylem towards periphery.
Question 4.
Differentiate between open and closed vascular bundle?
Answer:
Question 5.
Differentiate between protoxylem and metaxylem?
Answer:
Question 6.
Differentiate between Collateral and Bicollateral vascular bundle?
answer:
Question 7.
What are epidermal outgrowths?
Answer:
These are epidermal outgrowths present temporarily or permanently on almost all plant parts. They may be unicellular or multicellular and vary in size and shape in different species.
Question 8.
Why are stomata are sunken in xerophytes plants?
Answer:
To prevent water loss.
RBSE Class 11 Biology Chapter 14 Long Answer Type Questions
Question 1.
Name the three basic tissue systems in the flowering plants. Give the tissue names under each systems and functions of each one of them?
Answer:
Three basic tissue systems in flowering plants are:
1. Epidermal tissue system: It consists of
- Epidermis
- Cuticle and wax
- Stomata
- Trichomes
2. Ground tissue system: It consists of
- Cortex
- Endodermis
- Pericycle
- Medullary rays
- Pith
- Ground tissue of leaves
3. Vascular tissue system: It consists of (i) Xylem (ii) Phloem
The Epidermal Tissue System:
Originate from the outermost layer of apical meristem. Forms the outermost covering of various plant organs
which remains in direct contact with the environment. Performs manyfold function eg. Protection, absorption, excretion, secretion, gaseous exchange and control of transpiration etc.
1. Epidermis:
Epidermis (Greek, Epi = upon; Derma = skin) is generally uniseriate, i.e., composed of single layer of epidermal cells.These cells are of varying shapes and size and form a continuous layer interrupted by stomata. Sometimes they are separated by intercellular spaces (in petals of some flowers). In some cases epidermis may be multilayered eg.
Ficus, Nerium, Peperomia. The epidermis of Ficus elastica leaf is two layered and that of Peperomia pereskiaefolia is multilayered (13-14 layers).
The epidermal cells are living and may contain chloroplasts (shade plants, water plants, some ferns)., anthocyanin pigments, tannins, oils and crystals The cells are parenchymatous and living. The outer tangential walls are usually thicker as compared to inner tangential walls. Each cell has a large central vacuole and a peripheral thin cytoplasm. Certain epidermal cells of some plants or plant parts are differentiated into variety of cell types.
- In aerial roots, the multiple epidermal cells are modified to velamen, which absorb water from the atmosphere.
- Some of the cells in the leaves of grasses are comparatively very large, called bulliform or motor cells. They are thin-walled and contain big central vacuoles filled with water. They play an important role in the folding and unfolding of leaves.
- Some members of Gramineae and Cyperaceae possess two types of epidermal cells the long cells and the short cells. The short cells may be cork cells or silica cells
2. Cuticle and Wax:
Cuticle is a fatty substance (cutin) deposited over the outer surface of epidermal cells in the form of a separate layer. It is absent in young roots. The cuticle layer may be thin or thick and smooth or rough. Structurally a cuticle layer consists of cellulose lamellae interrupted with pectic substances and cutin. Usually the cuticle is covered with wax which may be deposited in the form of granules, rods, crusts or viscous semi liquid masses. Other substances, deposited on the cuticle surface may be. oil resin, silicon and salts (calcium oxalate or calcium carbonate).
3. Stomata:
Singular of stomata is stoma (Greek, stoma=mouth). A typical stoma is microscopic and usually consists of two kidney-shaped guard cells surrounding a pore. The guard cells are usually, much smaller in size as compared to other epidermal cells. They are, therefore, rapidly affected even by a small change in turgor.
The stomatal pore is generally elliptical in surface view. The dimension of stomatal pore varies from species to species, but on an average, it measures about 20 pm long and about 10-20 pm wide when fully open. In some species the guard cells are surrounded by subsidiary cells or accessory cells which differ morphologically from the other epidermal cells.
The guard cells generally have thick walls towards pore and thin walls on opposite side. Moreover, the cellulose micelles in guard cell walls are oriented radially rather than laterally. The guard cell walls have special elastic properties. The adjoining cell walls of two guard cells around pore are free and not attached with each other. These properties help them to stretch laterally during stomatal opening.
Basic functions of stomata include exchange of gases with atmosphere, transpiration and regulation of temperature In dicot plants maximun number of stomata are found in lower surface and either stomata are absent are few on upper surface, these leaves are called Hypostomatous. In monocots, equal no. of stomata are found on both surfaces and these leaves are called Amphistomatous. Stomata are absent in aquatic plants. Stomata are sunken in xerophytes.
These are epidermal outgrowths present temporarily or permanently on almost all plant parts. They may be unicellular or multicellular and vary in size and shape in different species.Trichomes are further classified into following types-
(i) Hair: These are elongated outgrowths of epidermis present in almost all the plant parts. Hairs are of two types-
- Unicellular hair: The epidermal cells elongate to form unicellular hairs. These may be short, long or coiled. Sometimes the unicellular hairs are branched but usually they are unbranched. They may be glandular or non- glandular. Examples stinging hair of Urtica dioca (glandular), silicified hairs of Cannabis, long and thick- walled hairs of Gossypium
- Multicellular hair: These hair are made up of more than one cells arranged either in one row (uniseriate) or in several rows (multiseriate). They may be unbranched (e.g., Tridax) or branched and dendroid (e.g., Withania). The cells may be dead or living.
(ii) Scales : These are also called peltate trichomes. Each scale has a mutlicellular discoid head borne on a short stalk.
(iii) Colleters : All the unicellular and multicellular trichomes that are glandular in nature are called colleters. Examples-stigmatic papillae, shaggy glands of Tabernaemontana.
(iv) Water vesicles or Bladders: These are swollen, bladder-like trichomes specially meant for storage of water
(v) Bulliform cells: Epidermal cells in some monocot leaves, become larger thin walled, have vacuoles and are called bulliform (bubble like) cells. These cells bring about rolling of leaves during dry season eg. Ammophila Epidermal Cells with ergastic substances: Epidermal cells outer layer secretes certain substances like silica, wax,oil,resins, salt precipitates etc.
- Silicocytes – silca precipates eg. Equisetum
- Lithocyte – Calcium carbonate crystals appears as bunch of grapes eg. Ficus, Cystolith
- Myrosine cells – Due to myrosine enzyme it swells up. eg. some plants of cruciferae
- Sclerotic cells – forms outer scleroids. e.g.,- seeds of urad and moong seeds.
Functions of Epidermal tissue system:
- Provides protection to the underlying tissues by forming a covering of all the plant parts.
- Helps in the reduction of surface evaporation of water due to presence of cuticle.
- All the gaseous exchange occurs through stomata and lenticels present in the epidermis.
- The water vesicles or bladders help in storage of water.
- The glandular trichomes excrete various plant products which perform various functions.
- The epidermis forms phellogen by induction of meristematic activity. It gives rise to cork layers and also helps in healing of wounds.
- The bulliform cells, present in the epidermis of some monocot leaves, help in the rolling and unrolling of leaves. This property helps to reduce transpiration in xerophytic plants.
Ground tissue system:
includes all the tissues of plant body except epidermal tissue system and vascular tissues. It forms the bulk of body and consists of mainly parenchymatous, collenchymatous, sclerenchymatous, glandular and laticiferous tissues. This tissue system mainly originates from ground meristem. The distinct regions of ground tissue system are cortex, hypodermis, endodermis, pericycle and pith. In some cases these regions are not clearly marked.
1. Cortex:
It is the region between the epidermis and endodermis (if endodermis is not considered as a part of cortex).
Morphologically this region consists of primary cells, specially parenchymatous, collenchymatous and sclerenchymatous. The cortex is distinct in dicotyledons but not in monocotyledons where there is no clear demarcation between cortex and pith. The cortex in roots usually homogenous and made up of one type of cells (parenchymatous), In case of stem the outer few layers of cells may be differentiated into hypodermis.
The hypodermis of dicotyledons stems may be collenchymatous, chlorenchymatous or sclerenchymatous whereas that of monocotyledons is usually sclerenchymatous. The hypodermis is mainly considered as the zone of protecting and supporting tissues.
2. Endodermis:
It is a single layer layers of compactly arranged parenchymatous cells present between the cortex and pericycle.
The cells of endodermis are elongated, without intercellular spaces and appear barrel- shaped, rounded or oval in transverse section. The endodermis of roots is more clearly distinct as compared to that of dicotyledonous stem where it may be present in the form of starch sheath.
The cells of endodermis are characterised to possess casparian strips or bands in their radial and transverse walls. These strips are made up of waxy substance like suberin and some other wall material which show lignin reaction.
The endodermal cells of roots usually have thick radial and inner tangential walls. These thick-walled cells form a continuous ring which is interrupted at certain places by passage cells.
The passage cells are thin-walled and usually present opposite to the protoxylem points. The endodermis of roots forms a water-tight jacket around the vascular cylinder and helps to maintain the root pressure. In case of stem it probably serves the function of storage of starch.
3. Pericycle:
Single layered or multi-layered cylinder of thin-walled or thick-walled cells present between the endodermis and vascular tissues. In some cases the pericycle is made up of many layer layers of sclerenchymatous cells (Cucurbita stem) or in the form of alternating bands of thin-walled and thick-walled cells (Sunflower stem). In case of roots, the pericycle is made up of thin- walled parenchymatous cells which later on gives rise to lateral roots. In dicot roots the cork cambium originates in the pericycle which results in the formation of periderm. Pericycle also gives rise to a part of vascular cambium in dicot roots.
4. Medullary Rays:
The primary medullary are present in between the adjacent vascular bundles in primary structure of dicot stem These are made up of parenchymatous cells and extend from pith towards the periphery. These cells originate from apical meristem. They serve the function of lateral transport.
5. Pith:
Central portions of root and stem are occupied by pith. Usually made up of parenchymatous cells with intercellular spaces. Sometimes, the pith becomes a hollow cavity (as in case of some water plants). In some cases, the pith may also contain sclerenchymatous cells, laticifers, secretory idioblasts and medullary vascular bundles embedded in the parenchymatous tissue. The main function of pith is storage of water and food reserves.
6. Ground tissue of leaves:
Ground tissue of petiole is made up of uniform parenchymatous cells with distinct intercellular spaces. In leaf lamina, the bulk of ground tissue is called mesophyll which is usually differentiated into palisade and spongy parenchyma.
These cells are thin-walled parenchymatous and possess chloroplasts. The main function of mesophyll is photosynthesis.
Vascular Tissue System:
This tissue system includes vascular tissues, i.e., xylem and phloem. The xylem and phloem strands are usually found in bundles, called vascular bundles. The main function of vascular bundles is conduction of water and minerals, translocation of organic solutes and to give mechanical support to the plant body. These tissues originate from procambium of apical meristem.
The phloeic pro-cambium gives rise to phloem and xyloic pro-cambium gives rise to xylem. In those plants where no secondary growth takes place, all the procambium matures into vascular tissues In those plants which show secondary growth, a portion of procambium remains meristematic. It is called vascular cambium. In case of dicot roots and a few monocot stems (Dracaena) the cambium originates from parenchymatous cells. It is secondary’ in origin. Normally the vascular cambium is absent in monocots. The vascular bundles are formed from centre to periphery (Centrifugal/acropetal).
The arrangement of xylem and phloem strands is the characteristic of a particular plant organ. However, a few exceptions are there. The following terms are commonly used to designate the types of vascular bundles and arrangements of xylem and phloem.
- Radial: The xylem and phloem strands alternate with each other separated by parenchymatous cells and found mainly in roots.
- Conjoint: Avascular bundle having both xylem and phloem together. Normally the xylem and phloem occur in the same radius. They occur in stems. Collateral: A vascular bundle in which the phloem lies towards outerside and xylem towards inner side, is called collateral, (e.g., Sunflower).
- Bicollateral: A vascular bundle having the phloem strands on both outer and inner side of xylem, is called bicollateral, (e.g., Cucurbita).
- Concentric: A vascular bundle in which one tissue is completely surrounded by the other, is called concentric. The concentric bundles are of two types-
- Amphivasal: The phloem lies in the centre and remains completely surrounded by xylem.
- Amphicribal: The xylem lies in the centre and remains completely surrounded by phloem.
- Open vascular bundle: If the cambium is present in the vascular bundle, it is called open.
- Closed vascular bundle: If the cambium is absent, the vascular bundle is called closed.
- Medullary bundles: The vascular bundles present in the pith.
- Cortical bundles: The vascular bundles present in the cortex.
Position of protoxylem in relation of metaxylem:
- Exarch: The protoxylem lies towards periphery and metaxylem towards centre.
- Endarch: The protoxylem lies towards centre and metaxylem towards periphery.
- Mesarch: The protoxylem remains surrounded on all the sides by metaxylem
Question 2.
Explain the different components of Cortex and thpir function ?
Answer:
1. Cortex:
It is the region between the epidermis and endodermis (if endodermis is not considered as a part of cortex).
Morphologically this region consists of primary cells, specially parenchymatous, collenchymatous and sclerenchymatous. The cortex is distinct in dicotyledons but not in monocotyledons where there is no clear demarcation between cortex and pith.
The cortex in roots usually homogenous and made up of one type of cells (parenchymatous), In case of stem the outer few layers of cells may be differentiated into hypodermis. The hypodermis of dicotyledons stems may be collenchymatous, chlorenchymatous or sclerenchymatous whereas that of monocotyledons is usually sclerenchymatous. The hypodermis is mainly considered as the zone of protecting and supporting tissues.
Question 3.
Differentiate between
(a) Radial, Conjoint, concentric vascular bundles
(b) Xylem and phloem
Radial, Conjoint, concentric vascular bundles:
- Radial: The xylem and phloem strands alternate with each other separated by parenchymatous cells and found mainly in roots.
- Conjoint: Avascular bundle having both xylem and phloem together. Normally the xylem and phloem occur in the same radius. They occur in stems.
- Collateral: A vascular bundle in which the phloem lies towards outerside and xylem towards inner side, is called collateral, (e.g., Sunflower).
- Bicollateral: A vascular bundle having the phloem strands on both outer and inner side of xylem is called bicollateral (e.g., Cucurbita).
Concentric:
A vascular bundle in which one tissue is completely surrounded by the other is called concentric. The concentric bundles are of two types-
- Amphivasal: The phloem lies in the centre and remains completely surrounded by xylem.
- Amphicribal: The xylem lies in the centre and remains completely surrounded by phloem.
- Open vascular bundle: If the cambium is present in the vascular bundle, it is called open.
- Closed vascular bundle: If the cambium is absent, the vascular bundle is called closed.
- Medullary bundles: The vascular bundles present in the pith.
- Cortical bundles: The vascular bundles present in the cortex.
(b) Xylem and phloem
| S.No | Property | Xylem | Phloem |
| 1. | Parts | Consists of tracheids, vessels, xylem parenchyma and xylem fibres. | Consists of selve tube companion cell,P.parenchyma and P. fibres. |
| 2. | Living or dead | Only xylem parenchyme is living. | Seive tube, companion cells and P. Parenchyme are living. Mature seive tube do not contain nuclei. |
| 3. | Function | Conduction of water or sap | Conduction of organic soluties. |
| 4. | Mechanical tissue | Yes | No |
| 5. | Presence of lignin | Yes | No |
| 6. | Wall thickenings | Yes | No |
| 7. | Location | Towards inner side of plant parts. lt constitutes the bulk. | Towards outer side of the plant parts. Constitutes small part of vascular tissue. |
Question 4.
Explain different types of vascular bundles with help of well labelled diagram?
Answer: