Discipline: Botany Paper: Plant Anatomy
Lesson: Plant Tissue Systems Lesson Developer: Dr Arun Kumar Maurya,
Dr Anita Rani Department/College: Dyal Singh College
Table of Contents
Lesson: Plant Tissue System
- Introduction
-
- Characteristic Properties of meristematic cells
Classification of Meristems
-
-
- Based on origin
- Based on location/position
- Based on differentiation
-
The Tissue System
-
- Classification
- Epidermal/Dermal tissue system
- Ground tissue system
- Vascular tissue system
- Classification
Summary
- Glossary
Exercises
- References
Introduction
The cell arises from preexisting cells. In plant body, diverse type of cells forms various types of tissues. Their structure and function are dependent on their location. These cells originated from specialized uncommitted cells known as meristematic cells.
Meristematic tissue
In vascular plant, zygote after the division produces new cells that develop into new organs. Later on embryo becomes an independent plant; the addition of new cells is gradually restricted to certain regions which remain embryonic in nature throughout plant life. Thus the plant body consists of mixture of embryonic and mature tissue. The embryonic tissues consisting of uncommitted cells which are primarily concerned with the formation of new cells are called as meristems. These cells are responsible for continuous growth of the plant body.
Figure: Meristamatic cells showing different divisional stages.
Source: http://quizlet.com/21508592/combo-with-biology-test-review-cellular-respiration- photosynthesis-dna-and-mitosis-and-1-other-flash-cards/
Characteristic properties
The characteristic features of meristematic cells are:
- Cells are small, rectangular or isodiametric compared to mature cells.
- The cells are compactly arranged i.e. they lack intercellular spaces between them.
- Each meristematic cell has a single conspicuous nucleus with transparent cytoplasm however, lacks vacuoles.
- The cell wall is thin made up of cellulose only.
- In meristematic cells, except mitochondria all the other organelles are either absent or if present as in plastids they are in a nonfunctional state and called as proplastids.
- These cells lack reserve food materials or secretory/ excretory products.
- The meristematic cells are inherently capable of undergoing regular and continuous mitotic divisions and chromosomes have a similar state of mitotic division.
Classification
The meristematic tissue can be classified on the basis of origin and development of initiating cells, plane of division, differentiation, functions and their location in the plant body.
Based on Origin
Plant meristem is classified into the following three types:
- Promeristem: It is also called as embryonic meristem or primordial meristem because it develops first in the embryo and later give rise to derivative cells that forms primary and secondary meristem. Promeristematic cells are isodiametric, thin walled, with dense cytoplasm and conspicuous nuclei.
- Primary meristem: It develops from the promeristem and continues to remain active throughout the plant life. Primary growth gives rise to the primary permanent tissues of plant body and is responsible for primary growth of the plant e.g. meristem found at the apex of the stem and root.
- Secondary meristem: Is the meristem that develops after the development of primary meristem by a process called de-differentiation in the permanent tissues. It is responsible for secondary growth of plant and give rise to secondary cortex and secondary xylem e.g. cork cambium (phellogen) and vascular cambium.
Figure: Diagrammatic representation of plant meristem based on origin. Source: http://bio1152.nicerweb.com/Locked/media/ch35/
Based on position or location
Based on location in the plant body, meristem can be classified into the following three types:
- Apical meristem: It is situated at the apex of the root and stem called as root and shoot apex, respectively. Apical meristems comprises of actively growing regions of plant which eventually helps in increasing the length of plant.
- Intercalary meristem: It is located between permanent tissues and represents the oddment of apical meristem. Intercalary meristem is generally found either at the nodal regions or at the base of the leaves. It contributes to the increase in length as it brings about elongation of internodal regions, for e.g. in bamboo and grasses. The apical and intercalary meristems are the examples of primary meristem.
Figure: Diagrammatic representation of shoot apical meristem and root apical meristem. Source: http://lurnq.com/lesson/Anatomy-of-Flowering-Plants-Part-I-Tissues/
Figure: Intercalary meristem in monocot (Bamboo).
Source: http://biologicalexceptions.blogspot.in/2013/08/go-prune-grass.html
- Lateral meristem: It is present laterally and parallel to the long axis of plant body. It is responsible for an increase in the thickness/ girth or circumference of the plant body and develops secondary permanent tissues. The lateral meristem is representative of secondary meristem.
Figure: A) Diagrammatic representation of lateral meristems B) a vascular bundle enlarged and C) Vascular cambium with secondary phloem (top) & secondary xylem (bottom).
Source: A) http://lurnq.com/lesson/Anatomy-of-Flowering-Plants-Part-I-Tissues/
Figure: Flow chart depicting classification of various types of tissue Source: http://biology4isc.weebly.com/1plant-anatomy.html
Based on differentiation
According to this, three types of meristems can be distinguished:
- Protoderm: It is also called as dermatogen, present as a thin outer layer of the meristem in embryos and growing points of roots and stems, which gives rise to the epidermis.
- Ground meristem: It differentiates into ground tissue which constitutes cortex, endodermis and pith. The cells of ground meristem are long and thin walled.
- Procambium: It differentiates into vascular tissues such as xylem and phloem. The cells of procambium are narrow, long and prosenchymatous in nature.
Figure: A) L.S. of shoot tip showing apical meristem, protoderm, ground meristem and procambium tissue B) L.S. of Coleus shoot tip showing two types of meristem protoderm and promeristem (a view enlarged).
Source:A)http://www.nana-bio.com/elearning/Meristem.htm; B)http://www.kbg.fpv.ukf.sk/studium_materialy/morfologia_rastlin/webchap6apmer/6.2- 2.htm
Figure: Diagramatic representation of the tissues that differentiates from the meristem. Source: http://biology4isc.weebly.com/1plant-anatomy.html
The tissue system
In plant body, various types of cells are present that form different types of tissues. Their structure and functions are dependent on location. The tissue system works in an integrated manner.
Classification
The cells in plant bodies make up tissues, groups of same kind of cells with a common structure and function. These tissues can be simple, consisting of a single cell type, or complex, consisting of more than one type of cell. The tissues can be classified on the basis of function, structure and location. Haberlandet (1914) used the functional aspect to classify the plant tissue and divided into three groups:
- Absorbing tissue system
- Mechanical tissue system
- Storage tissue system
On the other hand, Sachs (1875) recognized three types of tissue systems in plants on the basis of their structure and location:
- Epidermal tissue system,
- Ground tissue system and
- Vascular or conducting tissue system.
Epidermal/dermal tissue system
It forms the outer-most covering of entire plant structure. The epidermis originates in stem from the outermost layer (dermatogen) of apical meristem but in root it originates from independent group of initial cells. It consists of epidermal cells and associated structures such as stomata, epidermal appendages (trichomes and hairs) and periderm.
The epidermis is composed of elongated, compactly arranged parenchymatous cells, which form a single continuous layer without intercellular space. Epidermis covers and protects the
plant body acting as plant’s skin. The epidermal cells are living, exceptionally nonliving (velamen in Orchids) having cell walls thicker than other cells due to deposition of cutin, wax, resin, silica and gum. The epidermis is usually covered with a thick waxy layer called cuticle, which is secretory product of epidermal cells and help in the prevention of water loss through evapo-transpiration. Cuticle is absent in some parts of plant body such as root. However, epidermal cells may contain coloured pigments such as anthocyanin. Epidermal cells containing calcium carbonate crystals known as cystolith characteristic of family Moraceae, Apocyanaceae and Acanthaceae.
The epidermal tissue system of leaves and stems contain pores. Each pore is surrounded by living, two bean shaped cells known as guard cells. Two guard cells surrounding a pore is called as stomata. The epidermal cells close to the guard cells become specialized in their shape and size and known as subsidiary cells or accessory cells. The pore, guard cells and the surrounding subsidiary cells are together called stomatal apparatus. The cell wall of guard cells is differentially thickened with thin outer wall (away from the stomatal pore) and the thick inner wall (towards the stomatal pore). Differential thickening help in opening and closing of stomata which regulates the gaseous exchange between plant and environment. The guard cells possess chloroplasts, mitochondria, endoplasmic reticulum, dictyosome and ribosomes. Two shapes of stomata have been observed in plants, kidney shaped guard cells and dumb-bell shaped. Later type is found in grass family (Poaceae).
Figure: Diagrammatic representation of stomatal complex
Source: https://sciencevogel.wikispaces.com/Pictures++leaf+%26+stomata
Figure: A typical A) dicot and B) monocot stomata in Ocimum and grass respectively. Source: Dr. Arun Kumar Maurya
The epidermal cells bear a number of associated structures such as root hairs and trichomes. The root hairs are unicellular outgrowth of epidermal cell that absorbs water and minerals from soil. On the other hand unicellular or multicellular elongations of epidermal hairs on stem are called trichomes. They may be dead or living, secretory or non-secretory, branched or unbranched. The trichomes help in preventing water loss due to transpiration and provide protection as defense organ.
Figure: Trichomes on leaf petiole A) and leaf Surface B). Source: Author:
The periderm (bark) replaces the epidermis in plants that undergo secondary growth and forms protective covering layer outside stem and root. In contrast to epidermis, the periderm is multilayered and has three components cork cells (phellem), phelloderm, and phellogen (cork cambium). Cork cells are nonliving cells and have thick walls impregnated with suberin (a waxy substance) which provides protection by forming the insulatory layer. The corks found in wine bottles are cut from the bark of Quercus suber.
Figure: Diagram showing the different layers present in periderm. Source:http://www.life.illinois.edu/ib/423/lab_images_2005/jytang/Lab%2015/
The phelloderm may contain unsuberized, thin-walled parenchyma cells. Water and gaseous exchange occurs through openings present in periderm called lenticles. Although the function of lenticles is the same as the stomata but they cannot regulate the size of their openings. The periderm protects the plant from injury, wound, pathogens, prevents excessive water loss.
Ground tissue system
All tissues below epidermis excluding vascular tissue system or bundles constitute the ground tissue or fundamental tissue that includes parenchyma, collenchyma and sclerenchyma.
The ground tissue in the primary stems and roots such as cortex which is located outside the vascular tissue or bundle are called as extrastelar ground tissue and those located inside the vascular tissue are called as intrastelar ground tissue eg. pericycle, pith and medullary rays. In leaves, the ground tissue composed of thin-walled chloroplast containing cells which is known as mesophyll. Cortex can be further differentiated into hypodermis, general cortex, endodermis and exodermis. Hypodermis is located below the epidermal tissue system and
outermost layer of cortex and mainly consists of collenchyma and sclerenchyma cells. Hypodermis is responsible for mechanical function. General cortex is located below the hypodermis and consists of multilayered parenchymatous tissue with ample intercellular space. Cortex act as protective layer with photosynthetic and storage function.
Endodermis is a single layered consisting of barrel shaped cells with unique deposition of suberin that form casparian bands. Some cells are thin walled and they lack casparian strips called as passage cells which helps in the movement of water and mineral absorbed by the roots to the vascular system. Exodermis layer is found below the epidermis in roots. Pericycle is located in between the endodermis and vascular bundle and it delimits the external boundary of vascular bundles. The lateral root originates from the pericycle.
Pith forms the central portion of root and shoot and is intrastelar in nature. Pith is clearly well developed in dicot due to well-arranged nature of vascular bundle but in monocot they are not properly demarcated as the vascular bundles are scattered. Sometime due to degeneration of pith cells, the hollow region develops.
Vascular tissue system
It is formed by vascular bundles and originates from procambium present in apical meristem. The vascular bundles are made up of complex tissues, phloem and xylem. In dicotyledonous stems, cambium tissue is located between phloem and xylem. Cambium cells possess the ability to form secondary xylem and phloem tissues responsible for secondary growth. Vascular bundles with cambium are called open type vascular bundles. However in monocotyledons, the vascular bundles are closed type as they lack cambium tissue and thus don’t show secondary growth.
Xylem is made up of four types of cells known as tracheids, vessel elements, xylem parenchyma and xylem fibre. Tracheids and vessel elements are nonliving, tube-like structures and act as pathways for water and minerals to move from the roots to the leaves. Tracheids are distributed in all vascular plants but vessels are recently originated vascular tissue found exclusively in angiosperms.
Phloem consists of living sieve-tube cells, companion cells (Strausburger cell in gymnosperms), phloem parenchyma and nonliving phloem fibres. Phloem cells assist in translocation of food material synthesized during photosynthesis from the leaves to other parts of the plant.
Figure: Diagrammatic representation of different types of vascular bundles. Source:http://elte.prompt.hu/sites/default/files/tananyagok/plants_fungi/ch04s04.html
On the basis of arrangement of xylem and phloem, two types of vascular bundles have been recognized radial and conjoint. Radial condition of vascular bundles is found in roots where xylem and phloem within a vascular bundle are arranged in an alternate manner on different radius. In conjoint type of vascular bundles (common in stems and leaves) xylem and phloem are situated at the same radius of vascular bundles and usually have the phloem outside of xylem.
Vascular cambium is made up of two types of cells, fusiform and ray initials. Fusiform cells are conical and differentiate to give secondary xylem and phloem. The ray initial cells are isodiametric and after differentiation give rise to medullary ray. Monocot vascular bundles lack cambium and consequently don’t show secondary growth. On the other hand, dicot shows the secondary growth due to presence of cambium.
Figure: A cross section through a vascular bundle of a monocotyledonous plant A) and a dicotyledonous plant B).
Source: A) http://www.bcb.uwc.ac.za/ecotree/trunk/VasBundle1.htm
B) http://www.bcb.uwc.ac.za/ecotree/trunk/vasbundle.htm
| Tissue System and Its Functions | Component Tissues | Location of Tissue Systems |
Epidermal Tissue System
|
Epidermis Periderm (in older stems and roots) |  |
Ground Tissue System
|
Parenchyma Collenchyma Sclerenchyma | |
Vascular Tissue System
|
Xylem tissue Phloem tissue |
Table: Showing the type, function, component and location of tissue systems. Source: http://www.phschool.com/science/biology_place/biocoach/plants/tissue.html
Summary:
The embryonic tissue regions consist of uncommitted cells primarily concerned with formation of new cells, called as the meristems. The meristematic cells are rectangular or isodiametric, relatively small, compact, lack intercellular spaces and vacuoles. The meristematic tissue can be classified on the basis of origin and development of initiating cells, plane of division, function and location in the plant body and differentiation. Based on origin, meristem can be classified into promeristem, primary and secondary meristem. Based on location in plant body, meristem can be classified into apical, lateral and intercalary meristem. Based on type of permanent tissue that differentiates from meristem, protoderm, ground meristem and procambium have been recognized.
The cells in plant bodies make up tissues (groups of cells with a common structure and function). The tissues may be simple or complex. The tissues can also be classified on the basis of function, structure and location such as epidermal tissue system, ground tissue system and vascular or conducting tissue system. The epidermal tissue system develops the outer-most covering of the entire plant body. It consists of epidermal cells and associated structures such as stomata, epidermal appendages (the trichomes and hairs) and the periderm. All tissues below epidermis excluding vascular tissue system or bundles constitute the ground tissue or fundamental tissue. The components of simple tissues are parenchyma, collenchyma and sclerenchyma. The vascular tissue system is formed by vascular bundles and originates from procambium present in apical meristem. The vascular bundles are made up of complex tissues, the phloem and xylem.
Glossary
Apical Meristem: Actively dividing meristematic cells located at the apex of a root or shoot.
Abaxial: Directed away from the axis. .
Adaxial: Directed toward the axis and opposite of abaxial. It is used with regard to a leaf the upper or “ventral” surface.
Bark: The outer covering of the stem, branches and roots of trees.
Cambium: A layer of dividing cells found in the stems of plants which forms the specialized xylem and phloem cells and causes the stem to increase in thickness.
Companion cell: A specialized parenchyma cell associated with a sieve-tube element in angiosperm phloem.
Guard cells: A pair of cells covering the stomatal pore responsible for opening and closing of pore by change in turgor.
Intercalary meristem: Meristem located between permanent tissues and represents the oddment of the apical meristem.
Leaf primordium: A lateral outgrowth from the apical meristem that eventually will become a leaf.
Mesophyll: Photosynthetic parenchyma (Chlorenchyma) of a leaf blade located between the two epidermal layers.
Metaphloem: Part of primary phloem that differentiates after the protophloem and before the secondary phloem.
Metaxylem: Part of primary xylem that differentiates after the protoxylem and before the secondary xylem.
Parenchyma cell: Unspecialized cell having a nucleate protoplast and associated with one or more of various physiological and biochemical activities in plants. Parenchyma cells are diverse in size, form, and wall structure.
Petiole: Stalk attaching the leaf blade to the stem.
Phloem parenchyma: A type of Parenchyma cells located in the phloem and is referred as axial parenchyma in secondary phloem.
Phloem: It is main food-conducting tissue of vascular plant and contains sieve elements phloem parenchyma cells, fibres and sclereids.
Primary phloem: When procambium differentiates it give rise of phloem tissue during primary growth and differentiation of a vascular plant. It is then commonly divided into the earlier protophloem and the later metaphloem.
Protoxylem: First-formed elements of the xylem.
Ray parenchyma: It is a type of parenchyma cells found in secondary vascular tissues.
Sclerenchyma: It is a type of tissue composed of sclerenchyma cells that includes fibres, fibresclereids, and sclereids.
Sieve cell: Phloem component that has relatively undifferentiated sieve areas without sieve plates. Generally sieve cells are found in phloem of gymnosperms.
Sieve element: These are cell in the phloem tissue concerned with mainly longitudinal conduction of food materials.
Sieve plate: Part of wall of a sieve-tube element bearing one (simple sieve plate) or more (compound sieve plate) highly differentiated sieve areas.
Sieve tube: A series of sieve-tube elements arranged end to end and interconnected through sieve plates.
Sieve-tube element: Phloem tissue component that shows a more or less pronounced differentiation between sieve plates (wide pores) and lateral sieve areas (narrow pores).
Stoma (pl. stomata): An opening in epidermis of leaves and stems bordered by two guard cells and serving in gas exchange; also used to refer to entire stomatal apparatus—the guard cells plus their included pore.
Stomatal complex: Stoma and associated epidermal cells that may be ontogenetically and or physiologically related to the guard cells known as stomatal apparatus.
Strasburger cell: Few ray and axial parenchyma cells spatially and functionally associated with the sieve cells resembles the companion cells of angiosperms. However, they don’t not have common origin as seen in sieve cells and companion cells. They are also known as albuminous cells and are mainly associated with gymnosperm phloem.
Tissue: A group of cells organized into a structural and functional unit.
Tissue system: Structurally and functionally organized tissue or tissues in a plant or plant organ into a unit is called as tissue system. Three tissue systems are recognized in plants dermal, vascular and fundamental (ground tissue system).
Tracheary element: water conducting cell, tracheid or vessel element found in vascular system of plants.
Tracheid: A tracheary element of the xylem. It has no perforations as found in vessel element and may have any kind of secondary wall thickening. Tracheids occur in primary and in secondary xylem.
Vascular tissue: It refers to either or both vascular tissues, xylem and phloem.
Vessel element: One of the cellular components of a vessel.
Vessel: A tube-like series of vessel elements with common walls having perforations.
Xylem elements: It is a cell composing the xylem tissue.
Xylem fibre: A fibre of the xylem tissue.
Xylem ray: Part of a vascular ray that is located in the secondary xylem.
Xylem: It is a principal water-conducting tissue in vascular plants characterized by the presence of tracheary elements.
Exercises
Q1. What is meristem? Describe the basis of classification of meristematic tissue. Q2. Explain the characteristics of meristematic tissue.
Q3. What do you understand by tissue system? Explain the type of tissue system involved in plant body.
Q4. Describe the epidermal tissue system.
Q5. Elaborate the vascular tissue system found in angiosperms.
Q6. Differentiate between following:
-
- Primary and Secondary meristem
- Promeristem and Procambium
- Epidermis and Endodermis
- Ground tissue and Vascular tissue Q7. Write short notes on following topics-
- Cambium tissue
- Vascular bundle
- Intercalary meristem
- Periderm
Multiple choice questions:
Q1. The primary growth in plants is outcome of –
- Primary cambium activity
- Promeristem activity
- Lateral meristem activity
- Vascular cambium activity
Correct Answer:
Feedback for answer:
Promeristem is also known embryonic meristem or primordial meristem. It develops firstly in the embryo and give rise of derivative cells that forms primary and secondary meristem.
(b) Promeristem activity
Resource/Hint/feedback for the wrong answer:
The vascular cambium/primary cambium/ cambium are a lateral meristem in the vascular tissue of plants responsible for increase in thickness of plant body.
Q2. Which one is not a part / component of epidermal tissue system-
- Epidermis
- Mesophyll cells
- Bulliform cells
- Stomata
Correct Answer:
(b) Mesophyll cells
Feedback for answer:
Mesophyll cells are photosynthetic parenchyma cells that lie between the upper and lower epidermis layers of a leaf
Resource/Hint/feedback for the wrong answer:
Epidermis forms outermost layer found in plant body.
Bulliform cells are large, bubble-shaped epidermal cells present in groups on the upper surface of the leaves of grasses.
Stomata are small opening present on epidermis that help in gaseous exchange
Q3. Plant meristems are found in which plant part(s):
- Cycas stem
- Moss leaves
- Pollens of Brassica
- Flower of Brassica
Correct Answer:
(a) Cycas stem
Feedback for answer:
Meristematic tissue in plants are present in the plant where active growth take place such
as shoot apex present on tip of stem (Cycas).
Resource/Hint/feedback for the wrong answer:
Moss leaves don’t have meristematic tissue
Pollen and flower of Brassica donot show meristematic tissue.
Q4. In angiosperm, the stem contains intercalary meristem which gives rise to:
- Secondary growth
- Primary growth
- Apical growth
- Periderm development
Correct Answer:
b) Primary growth
Feedback for answer:
The function of an intercalary meristem is to facilitate longitudinal growth of a plant organ, independent of activity of the apical meristem that result in primary growth.
Resource/Hint/feedback for the wrong answer:
Secondary growth in plants results from cell division in the cambium causes the stems and roots to thicken.
Apical growth occurs at apex of shoot or root by division of that contribute to primary growth.
Q5. Increase in diameter of stem occur due to activity of-
- Ground tissue
- Procambium
- Cork
- Vascular cambium tissue
Correct Answer:
d) Vascular cambium tissue
Feedback for answer:
Secondary growth in plants results from cell division in the vascular cambium causes the
stems and roots to thicken that eventully contribute to the increase in diameter.
Resource/Hint/feedback for the wrong answer:
Cork (Phellum) is dead air-filled protective tissue at maturity and forms cork of commerce.
The procambium is a dividing meristematic tissue contributes to the formation of the primary tissues of the vascular system.
The ground tissue are the tissue which neither dermal nor vascular and present between them such as hypodermis, cortex and endodermis.
Q6. Bamboo, grass (grass family members) and mint stem elongates by the activity of which tissue?
- Primary meristem
- Secondary meristem
- Intercalary meristem
- Apical meristem
Correct Answer:
(c) Intercalary meristem
Feedback for answer:
The function of an intercalary meristem is to facilitate longitudinal growth of a plant organ,
independent of activity of the apical meristem that result in primary growth.
Resource/Hint/feedback for the wrong answer:
he primary meristem located at the tips of stems or roots is known as the apical meristem, responsible for increase in length.
Secondary meristem (vascular cambium and cork cambium) is located laterally and responsible for increase in thickness of plant stem and root.
Q7. Closed type vascular bundles present in monocotyledons plants characterized by
- Paranchymatous layer surrounds each bundle
- There are no vessels with perforations
- Xylem is surrounded all around by phloem
- Absence of secondary growth
Correct Answer:
(d) Absence of secondary growth
Feedback for answer:
Closed collateral bundles lack secondary growth, because they contain no cambium and present in almost all monocotyledonous plants.
Resource/Hint/feedback for the wrong answer:
There is bundle sheath surrounding each bundle and xylem contains vessels with perforation. The xylem can be surrounded all around by phloem and such condition is called as amphicribral condition.
Q8. Which component is absent in closed vascular bundles
- Cambium
- Pith
- Phellogen
- Conjunctive tissue
Correct Answer:
Feedback for answer:
(a) Cambium
Closed vascular bundle lack cambium between phloem and xylem.
Resource/Hint/feedback for the wrong answer:
Pith, ground tissue and conjunctive tissue is present in plants which shows closed vascular
bundles.
Q9. The common bottle cork is a product of
- Xylem
- Phloem
- Phellum
- Phelloderm
Correct Answer:
(c) Phellum
Feedback for answer:
Cork is an impermeable, buoyant plant material and component of bark tissue that is
harvested for commercial use from plant known as Quercus suber (the Cork Oak)
Resource/Hint/feedback for the wrong answer:
Xylem and phloem are vascular tissue concerned with transport of water, mineral and food materials in plants respectively.
Phelloderm is a layer of parenchyma cells produced inwardly by the activity of meristematic cork cambium cell layer. It makes an inner secondary cortex of the cork cambium.
Q10. Which is the correct sequence of arrangement of tissues in bicollateral vascular bundle
- Outer Phloem – Outer Xylem – Middle Cambium – Inner Xylem – Inner Phloem
- Outer Xylem – Outer Cambium – Middle Phloem – Inner Cambium – Inner Xylem
- Outer Phloem – Outer Cambium – Middle Xylem – Inner Cambium – Inner Phloem
- None of the above
Correct Answer:
(c) Outer Phloem – Outer Cambium – Middle Xylem – Inner Cambium – Inner Phloem
Feedback for answer:
A vascular bundle having xylem in between the two phloem groups
Resource/Hint/feedback for the wrong answer:
- Outer Phloem – Outer Xylem – Middle Cambium – Inner Xylem – Inner Phloem is wrong combination
- Outer Xylem – Outer Cambium – Middle Phloem – Inner Cambium – Inner Xylem is wrong combination
References
- Esau, K. 1965. Plant Anatomy. Jhon Wiley and Sons Inc., New York.
- Ray F. Evert. 2006. Esau’s Plant Anatomy: Meristems, Cells, and Tissues of the Plant Body: Their Structure, Function, and Development, Third Edition. Jhon Wiley and Sons Inc., New York.
- Fahn, A. 1990. Plant Anatomy. Pergamon Press, Oxford.
- William C. Dickison. 2000. Integrative Plant Anatomy, Academic Press.
- V. Singh, P.C. Pande, D.K. Jain. 2005. Anatomy of Seed Plants, Rastogi Publications, Meerut.
- Websites motioned with Photographs and texts