The document details the classification, occurrence, structure, and development of plant fibers, specifically focusing on sclerenchyma and its two primary types: xylary and extraxylary fibers. It describes various types of fibers present in vascular tissues, outlines their evolutionary background, and explains the developmental processes from different meristems. Key distinctions are made between libriform fibers, fiber-tracheids, and their molecular characteristics, emphasizing the functional diversity and structural complexity of these plant fibers.

1. PLANT FIBERS
Submitted to,
Dr. Chandini V. K
Asst. Professor
ST. Teresa’s College, Ekm
Submitted by,
A.T Milin Sera
Roll no : 1
1st M.sc. Botany
ST. Teresa's College, Ekm

2. INTRODUCTION TO FIBRES
• Sclerenchyma is a tissue composed of cells with
thickened secondary cell walls.
• Their cell walls may be lignified or not and contain pits.
• Their principal function is support and sometimes
protection.
• Sclerenchyma cells may differ in shape, structure, origin
and development.
• Generally, sclerenchyma is divided into fibres and
sclereids.
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3. 2

4. FIBRES
• Fibres are elongated cells often with pointed ends, thick
secondary wall and reduced pits.
• Certain other types of fibres possess blunt or even branched
ends.
• As the fibres get old, the protoplasmic contents become
multinucleate and finally disappear.
• But in certain cases, fibres retain protoplast even upto the
permanent stage.
• Some fibre walls contain lignin while certain fibres like those
occurring in flux (Linum usitatissimum) the wall is made up of
pure cellulose.
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5. OCCURRENCEOFFIBRES
• Fibres occur in different parts of the plant body.
• They may occur singly as idioblasts (e.g. in the leaflets of
Cycas).
• But more usually they form bands or a network or an
uninterrupted hollow cylinder.
• They are most commonly found among the vascular tissues
but they are also well developed in the ground tissues.
• Gymnosperms usually have no fibers in the primary
phloem, but many have them in the secondary phloem.
• In Gramineae the fibers form a system having the shape of
a ribbed hollow cylinder, with the ribs connected to the
epidermis.
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6. • In Zea, Saccharum, Sorghum the vascular bundles,
particularly the peripheral ones, have prominent sheaths
of fibers.
• Fibers may be prominent in the leaves of monocotyledons.
• They form sheaths enclosing the vascular bundles, or
strands extending between the epidermis and the vascular
bundles.
• In stems of dicotyledons, fibers frequently occur in the
outermost part of the primary phloem.
• Others develop fibers in the secondary phloem (Nicotiana,
Ulmus).
Monocot stem
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7. • Some dicotyledons have complete cylinders of fibers.
• They are located to the inside of the inner- most layer of
the cortex (Cucurbita).
• A highly characteristic position for fibers in the
angiosperms is in the primary and the secondary xylem.
• Roots may have fibers in the primary and in the
secondary body.
Dicot
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8. CLASSIFICATIONOFFIBRES
• According to their position in the plant body, fibres are
classified into two basic types xylary and extraxylary fibres.
1.) Xylary fibres : constitute an integral part of the xylem
and they develop from the same meristematic tissues as the
other xylem elements.
• These fibres are of varied shape in spite of their common
origin.
• Two main types of xylary fibres, i.e. libriform fibres and
fibre-tracheids, are distinguished on the basis of wall
thickness and type and amount of pits.
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9. • Libriform fibres : resemble phloem fibres (liber- inner bark).
• They are usually longer than the tracheids of the plant in
which they occur.
• These fibres have extremely thick walls and simple pits.
• Fibre-tracheids : are forms intermediate between tracheids
and libriform fibres.
• Their walls are of medium thickness-not as thick as those of
the libriform fibres but thicker than those of the tracheids.
• The pits are bordered but their pit chambers are smaller than
those of tracheids.
Libriform fibres
Fibre tracheids
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10. • Another type of fibre present in the secondary xylem of
dicotyledons is the gelatinous or mucilaginous fibre.
• Mucilaginous fibres : are fibres in which the innermost
layer of the secondary wall contains much cellulose and is
poor in lignin.
• This layer, termed the “G-layer”, absorbs much water and
may swell so as to fill the entire lumen of the fibre.
• The G-layers were found to be relatively porous and less
compact than the adjacent outer layers.
• Septate fibres : are characterized by the presence of
internal septa and, usually, of a living protoplast.
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11. • The internal septa result from mitosis in lignified cells.
• The septum does not fuse with the fibre wall but becomes
broadened, at the place of contact with it.
• The tips are running out as pointed ends when viewed in
longitudinal section of the fibre.
• The septum consists of a middle lamella and two primary
wall-like layers interrupted by numerous plasmodesmata.
• Septate fibres may contain starch and oils and, therefore, are
thought to have a storage function.
• They may also contain resins and sometimes crystals of
calcium oxalate.
Septate fibres with radial canal
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12. • There is also some elongated cells that sometimes occur in
the secondary xylem.
• Their secondary walls are equal in thickness to those of the
xylem parenchyma and contain living protoplasts.
• According to Haberlandt (1918), they were termed by Sanio,
substitute fibres (Ersatzfasern).
• It appears that these cells should be included among the
xylem parenchyma.
• They should not be confused with the living libriform fibres
and fibre-tracheids.
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13. 2.) Extraxylary fibres : occur elsewhere in the plant
other than among the xylem elements.
• Phloic or phloem fibers : fibers originating in primary or
secondary phloem.
• Cortical fibers : fibers originating in the cortex.
• Peri - vascular fibers : located on the periphery of
vascular cylinder inside the innermost cortical layer but
apparently not originating in the phloem.
• In the stems of many monocotyledons, the extraxylary
fibres occur in an uninterrupted hollow cylinder in the
ground tissue.
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14. 13

15. • In the stems of climbing and certain other dicotyledonous plants
(Cucurbita), fibres are found on the innermost cortical layer and
on the periphery of the central cylinder.
• These fibres are not developmentally connected with the
phloem, they were termed as pericyclic fibres by many workers.
• As a result of ontogenetic studies in stems of some plants
(Nicotiana, Linum, Nerium) it has been concluded that the so-
called pericyclic fibres develop from the procambium and thus
represent primary phloem fibres.
• The extraxylary fibers are sometimes combined into a group
termed bast fibers.
• The bast (to bind) was originally applied to fiber strands
obtained from the extracambial region of dicotyledonous stems.
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16. 15

17. ORIGINOFFIBRES
• Fibers arise from various meristems.
• Fibers of the xylem and the phloem are derived from procambium or cambium.
• In the cambium, the fibers arise from the fusiform initials.
• Extraxylary fibers other than those of the phloem arise from the ground
meristem.
• In some Gramineae and Cyperaceae, fibers originate in the protoderm and
become elements of the epidermis.
• In plants having fibrous bundle sheaths, part of the fibers may be derived from
the procambium and part from the ground meristem.
• The fibrous bundles of monocotyledons appear to be connected with vascular
bundles and they are considered as originating from the procambium.
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18. STRUCTUREOFFIBRES
(I) Extraxylary Fibers : A long spindle-like shape is considered
typical of extraxylary fibers (fibers in general).
• These elements may vary in length, and their ends are
sometimes blunt, rather than tapering, and may be branched.
• Generally, primary extraxylary fibers are longer than the
secondary.
• The cell walls of the extraxylary fibers are frequently very
thick.
• The pits are simple or slightly bordered.
• Some extraxylary fibers have lignified walls, others non-
lignified.
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19. • The flax fiber (Linum usitatissimum) is typically not lignified,
its secondary wall consists of almost pure cellulose.
• Concentric lamellations may be observed in extraxylary
fibers with or without treatment with swelling reagents.
• This lamellation appears to result from an alternation of
cellulosic and noncellulosic layers.
• In cotton fiber, the lamellation is a reflection of varying
densities of the cellulosic matrix in the successive lamellae.
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20. (II) Xylem Fibers : Wood fibers typically have lignified
secondary walls.
• They vary in size, shape, thickness of wall, and type and
abundance of pitting.
• With reference to the possible evolution of the xylem
fibers, different categories of these fibres are understood.
• Phylogenetically, these fibers are believed to be derived
from an imperforate xylem cell combining the functions of
water conduction and support, that is, a tracheid.
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21. • A good indication that fibers and tracheids are phylogenetically related is the
occurrence of almost imperceptible gradations between these two cell types in
certain angiosperms such as the oak.
• The gradations suggest the following principal changes during the evolution of
the fiber from a tracheid:
(i) increase in wall thickness, (ii) decrease in length, and (iii) reduction in the size of
bordered pits.
• In the extreme condition the pit appears simple or nearly so.
• Wall thickness and the nature of pitting are used to differentiate between the
two main categories of wood fibers, fiber-tracheids and libriform fibers.
• Fiber-tracheids are cells with pits whose borders are reduced as compared with
those in the tracheids.
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22. • Finally the cells with simple pits are classified as libriform fibers.
• Commonly, the thickness of wall increases in the sequence of tracheid, fiber-
tracheid, libriform fiber.
• The increase in wall thickness results in an increase in the length of the pit canal.
• In the fiber-tracheid these canals lead into small but evident pit chambers.
• In them the inner apertures are lenticular to slit-like and usually extended beyond
the outlines of the border.
• The libriform fibers also have long slit-like canals, but their pit chambers are much
reduced or absent.
• The inner apertures of the pit-pairs in the fiber-tracheids and libriform fibers are
often crossed with each other.
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23. • The tracheids are usually shorter, the fibers longer, with
the libriform fibers attaining the greatest length.
• The fibers become longer than the associated tracheids
because they undergo a more extensive apical
elongation during tissue differentiation.
• Fiber-tracheids and libriform fibers may both be septate.
• The septa are true walls, but they are formed after the
deposition of the secondary layers on the longitudinal
walls of the element.
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24. • Parts of the secondary wall of fiber-tracheids and libriform fibers may have a
great capacity for absorption of water.
• In the presence of water such walls swell. Upon drying, these walls shrink again.
• Fibers possessing hygroscopic walls are sometimes termed mucilaginous or
gelatinous.
• The gelatinous wall layers do not contain excessive amounts of pectinaceous,
gummy, or mucilaginous substances.
• They show a peculiar physical condition of the cellulose which possibly is
responsible for their gelatinous nature.
• Many woods contain gelatinous fibers. Oak (Quercus) and black locust (Robinia)
are noteworthy examples.
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25. EVOLUTIONOFXYLARYFIBRES
• From the evolutionary point of view, xylary fibres have developed from tracheids.
• This assumption is supported by the fact that many transitional forms between
these two types of elements are found in some angiosperms, e.g.:- Quercus spp.
• It is assumed that the following changes have taken place during the course of
the evolution of fibres from tracheids :
(i) The wall has become thickened.
(ii) The number of pits and the size of the pit chamber has been reduced leading
to the eventual disappearance of the bordered pit.
(iii) The cells have become shortened.
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26. • This assumed shortening of the fibres refers to the
shortening of the initials of the fibres in the cambium
and not to the mature fibres.
• In the mature tissues of one plant, the libriform fibres
are usually longer than the tracheids.
• This increased length is secondary and is the result of
the additional growth of the ends of the fibres.
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27. FORMANDLENGTHOFFIBRES
• Fibres are usually very long and narrow cells with tapered, and sometimes
branched, ends.
• The length of fibres varies very greatly and generally extraxylary fibres are longer
than xylary fibres.
• In Cannabis sativa (hemp) the fibres are 0.5-5.5 cm long.
• In Linum usitatissimum (flax), fibres are 0.8 to 6.9 cm long.
• In Boehmeria nivea (ramie) the fibres may reach a length of 55 cm.
• These ramie fibres are among the longest cells in the higher plants.
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28. DEVELOPMENT OFFIBRES
• Ontogenetically fibres develop from different meristems, such as the
procambium, cambium, ground meristem and even from the protoderm.
• Fibres may also develop from parenchyma cells, e.g. in the protophloem of many
dicotyledons.
• The fibres formed by the cambium develop from fusiform initials and elongate
only little or not at all during their maturation.
• Fibres that arise from short initials, as in Linum (flax) and Boehmeria nivea
(ramie), must necessarily elongate greatly in the course of their maturation.
• The elongation is very gradual and may take some months.
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29. • This gradual elongation of primary phloem fibres involves a very complicated
development of the secondary wall.
• While the fibre still grows symplastically, the wall remains thin.
• Later, when the ends begin to grow by intrusive growth, only the cell walls of
the ends remain thin.
• Secondary wall formation commences from the middle of the fibre in those
parts of wall which have ceased to elongate.
• In Linum and ramie it has been found that this process is gradual.
• So the new lamellae of the secondary wall are added centripetally in the form
of cylinders which are open at both ends.
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30. • At the same time the first-formed lamellae continue to
elongate towards the fibre ends which they reach only
when the fibre ceases to elongate.
• According to Kundu and Sen (1960) the upper ends of ramie
fibres continue to grow for a longer period than the basal
ends.
• Sometimes not all the lamellae reach the actual fibre end.
• In some fibres, chambers may be formed in the terminal
portions by the ingrowth, towards the cell lumen, of these
lamellae.
• The lamellae of the primary phloem fibres, or at least of the
immature fibres, are often not strongly attached to one
another.
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31. • In short fibres, such as those found in Agave, Sansevieria, and
Musa textilis, all portions of the cell wall grow at the same
rate.
• Differences exist in the manner of growth of the fibres in the
primary body and of those in the secondary body.
• The initials of the primary fibres appear early, before the
organ in which they occur has elongated.
• So they may grow in length symplastically together with the
neighboring cells which continue to divide.
• The symplastic growth is augmented by intrusive and gliding
growth of the ends which thus penetrate between the
surrounding cells.
• The initials of the secondary fibres develop in organs that
have ceased to elongate.
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32. • Therefore the growth of secondary fibres can be intrusive only.
• This is apparently the reason why the primary fibres are usually longer than the
secondary fibres of the same plant.
• Electron microscopic studies of wood fibres have shown that during secondary
wall formation the cytoplasm was in general conspicuously vacuolated, although
the vacuolation did not extend to the cell tips.
• The nucleus was large and the organelles which were generally few in number
appeared more crowded near the tips.
• The ER frequently appeared to lie parallel to the wall surface.
• In the process of wall formation, lamellar apposition of cellulose and vesicular
secretion of matrix takes place.
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33. FIBREPROTOPLAST
• During the development of primary phloem fibres of Nicotiana and Linum, the
protoplast was multinucleate.
• The protoplast in developing secondary fibres usually has a single nucleus.
• Mature libriform fibres and fibre-tracheids were usually regarded as being dead
supporting structures.
• In mature fibres the presence of a living protoplast and nucleus had been
described only in phloem fibres and in septate fibres.
• According to Bailey (1953), libriform fibres sometimes retain their living contents
subsequent to the formation of the thick, lignified secondary wall, thus enabling
these cells to assume a storage function in addition to that of support.
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34. • Recently, however, living protoplasts and nuclei have been identified in libriform
fibres of many species, and even in fibre-tracheids.
• Such living fibres were found to occur in the wood of Tamarix spp., and in many
other woody species.
• Living protoplasts have also been found in many monocotyledonous fibres.
• In fibres with long, narrow lumina the nuclei are usually elongated.
• During the elongation of the primary phloem fibers in tobacco, the protoplasts
become multinucleate as a result of repeated mitotic divisions.
• Cell plates do not form at the ends of the successive nuclear divisions and the
spindle fibers are less persistent than in ordinary division.
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35. • At the final stages in fiber ontogeny, usually after secondary walls have
developed, the nuclei appear to fuse or clump.
• In nearly mature fibers the nuclear material frequently occurs as one large
degenerating mass.
• The bast fibers of Linum also exhibit a multinucleate phase during differentiation.
• Haberlandt (1914) observed a multinucleate protoplast in the bast fibers of Linum
and certain members of the Leguminosae.
• He suggested that, the presence of several nuclei appears advantageous when
the length of many bast-cells and their active growth in length and thickness are
taken into account.
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36. • In certain types of fibers, however, mitosis is
followed by cytokinesis, resulting in a
chambered or septate fibre.
• In Hypericum androsaemum the fiber-
tracheid retains its protoplast after the thick
secondary wall has been laid down.
• Mitosis may then occur in such a cell.
• Cell plate formation then occurs in the
normal manner.
• A thin transverse septum is formed across
the lumen, intersecting the inner edge of the
secondary wall of the “mother cell.”
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37. STRUCTURE&USEOFCOMMERCIAL
FIBRES
• The term fibre, as used in industry, does not generally have the same meaning as
that defined by botanists.
• For instance, the commercial fibres of Linum, Boehmeria, and Corchorus are, in
reality, a bundle of fibres.
• Those from monocotyledonous leaves, such as from Agave, Musa textilis, and
others, are usually the vascular bundles with the surrounding sheaths of fibres.
• From some plants the commercial fibres comprise the vascular system of the
root, e.g. Muhlenbergia, or of the entire plant, e.g. Tillandsia.
• The commercial fibres of Gossypium (cotton) and kapok are the epidermal hairs
of the seeds.
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38. Linum usitatissimum
Linen
Musa textilis Abaca
37

39. • Commercial fibres are divided into two types - hard fibres and soft fibres.
• Hard fibres : are those which have a lignin content in the walls, and are of a stiff
texture.
• They are obtained from monocotyledons.
• Soft fibres : may or may not contain lignin, they are flexible and elastic.
• They are of dicotyledonous origin.
• The best- known plants from which hard fibres are produced are different species
of Agave, especially sisalana (sisal), Tillandsia usneoides (Spanish moss), Musa
textilis (abaca), Fureraea gigantea (Mauritius hemp).
• Soft fibres are mainly produced from Linum usitatissimum (flax), Cannabis sativa
(hemp), Boehmeria nivea (ramie), Corchorus capsularis (jute), Hibiscus
cannabinus (kenaf).
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40. 39

41. • The fibres of cotton, which are produced from the indumentum of seeds,
represent the most important commercial fibres in use today.
• Fibres are also classified according to their use :
(a) Textile fibres :- which are used in the manufacture of fabrics.
(b) Cordage fibres :- used for making cordages.
(c) brush fibres :- which are used in the manufacture of brushes and brooms.
(d) filling fibres :- such as those used for stuffing upholstery, mattresses and life-
belts, caulking (barrels, plumbing), and reinforcing (wall plates, plastics).
• In the textile industry the principal fibre used is cotton and, in smaller amounts,
flax, ramie, and hemp.
• For coarser fabrics, such as sacking and bagging, jute is principally used, and
cotton, flax, hemp, and a few other hard fibres are used to a lesser extent.
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42. Cordage
Filling fibre Brush fibres
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43. • For the manufacture of twine ; jute, cotton, hemp and, to a lesser extent, flax
and several hard fibres are used.
• Ropes and binder twines are manufactured from hard fibres, such as those of
Musa textilis (abaca) and Agave spp. (sisal), and to a small extent from cotton
and other soft fibres.
• Brushes and brooms are made from Agave fibres, fibres from the stems and
leaves of the Palmae and the inflorescences of Sorghum vulgare, etc.
• As filling fibres, the fibres of Ceiba pentandra (kapok), cotton, jute, the fibres of
Tillandsia usneoides, several hard fibres, and others are used.
• Fibres are also used in the paper industry, depending on their physical and
chemical properties different types of paper can be made.
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44. 43

45. • From a technological point of view, the shape of the fibre cell, its length, and
wall structure are of importance in the fibre industry.
• Special attention is paid to the length of the fibre, the extent to which
neighboring fibres overlap, and how they are joined to one another.
• The orientation of the cellulose units in the wall has an important effect on the
physical properties of wood and commercial fibres.
• Elasticity and heat conductivity increase as the degree of orientation parallel to
the length of the fibre increases.
Cannabis
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46. PREPARATIONOFCOMMERCIAL
FIBRES
• In the preparation of commercial fiber the plants are
subjected to a process of partial maceration called
retting (technical form of the word rotting).
• In this process the plant material is exposed to a
decomposing action by bacteria and fungi.
• These are allowed to act on the plant parts until the
tissues surrounding the fibers are so softened that
the fibers can be easily freed mechanically.
• The tissues are left in water for a considerable time
while this takes place.
• In the early stages of retting only the intercellular
material is affected by pectic enzymes.
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47. • Later the primary wall may be also attacked.
• An effort is made to discontinue the retting process
before the fiber strands are macerated into
individual cells.
• Then the retted stems are dried and passed
between rollers, which separates the fibres from the
other tissues.
• Finally they are combed, beaten out and placed in
bales.
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48. COTTON
• It is one of the most important industrial products.
• It is the principal textile fiber and also the oldest and
the most economical one.
• Several species like Gossypium herbaceum, G.
arboretum, G. barbadense, G. hirsutum yield cotton.
• Gossypium herbaceum appears to be the most
important, as it is the chief species cultivated in
Asia.
• Its fiber is widely used in fabric industry in India and
in other Asian countries.
Gossypium
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49. • In a strict anatomical sense, the “fiber” of a cotton seed is
not really a fiber at all.
• Because it is not lignified nor does it occur in the appropriate
part of the plant to be called a fiber.
• The proper anatomical cell name for the seed “fiber” is a
trichome.
• However, we will adopt the term “fiber” to describe the long
hairs on the cotton seed as that is the commonly used term.
• Each “fiber” is produced by the outgrowth of a single
epidermal cell.
• The “fibers” are actually hairs that grow out of the seed
coats.
Processed fibres of Gossypium
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50. • The seed “Fiber” is composed of :
(i) cuticle: mixture of cutinous, pectinous substance.
(ii) outer cellulose layer: mostly original cell wall.
(iii) layer of secondary deposits: almost all cellulose.
(iv) walls of lumen: spiral structure surrounding the central cavity, most dense part
of the “fiber”.
(v) lumen: filled with structure less substance, nitrogenous nature.
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51. • Some epidermal cells make long lint hairs.
• Other cells stop growing before they become too long; we call these fuzz hairs.
• The fuzz hairs have a bigger diameter and a thinner cell wall.
• As the boll grows, the “fibers” are maturing within.
• In about four months times the boll begins to slit open and the “fibers” are
exposed.
• Each seed has about 10,000 to 20,000 “fibers”.
• The boll matures and the “fibers” lose their water and die.
• Each “fiber” collapses and appears as a flattened twisted tube.
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52. • The degree of twist is a result of the type of environment the plant is grown in,
the specific species or cultivar, and the ripeness of the “fibers”.
• The twists cause the “fibers” to cling to each other and improve their spinning
qualities.
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53. JUTE
• Jute is the bast fiber obtained from the secondary
phloem of plants called Corchorus capsularis and
Corchorus olitorius.
• Their fiber is cheaper than cotton and flax.
• The plant is tall slender annual one with shrubby
nature.
• The fibre surrounds the woody central part of the
stem.
• In fact, it is located in wedge-shaped bundles outside
the xylem.
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54. • Fibres are grouped in concentric rings alternating with the thin walled tissue.
• This thin walled phloem tissue breaks up through microbiological decomposition
during retting.
• At maturity, these fibres lose their protoplasm and become dead.
Corchorus olitorius Corchorus capsularis
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55. • They are elongated, unbranched, sclerenchymatous cells
with very thick cell walls.
• These fibres are longer than a meter in comparison to the
fibres in fruits or seeds.
• The stem is retted in water and the long fibers are separated
from the phloem part.
• The pale yellow fibers are obtained during this process.
• Jute is used to produce rough wearing, bags, sacs and
wrapping materials for textile industry.
• The fibers are twisted to produce twine, coarse cloth, and
curtains, manufacture of paper etc.
• India is the best producer of jute.
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56. COIR
• Coir is a hard, versatile, natural fibre.
• The coir is obtained from the mesocarp of the fruit.
• Coir fibre is generally not very long (0.15—0.28 m).
• The coir fibre is multicellular (the fibre contains 30
to 300 or more cells in its total cross-section) and its
cross-section is polygonal or round.
• The transverse and longitudinal section of coir fibre,
shows the number of cells and distribution of cells
around the central pore called ‘lacuna’.
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57. • The walls are thin to fairly thick with lense-shaped silicified stegmata on their
surface.
• These are delicate thickenings with a few of them being circular or spiral in shape.
• There is a central cavity in each cell called lumen, which is medium to large in size
(polygonal, round or rounded to elliptic in shape).
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58. • The surface of the individual cell is smooth or rough with
certain defects like cross-markings, while the surface of
the fibre is coated with a waxy material called cuticle.
• The chemical constituents of pure coir fibre have been
found to be cellulose, lignin, hemicellulose, pectin and
water solubles.
• The ageing of the fibres is found to render the fibres
stiffer and tougher, and leads to an increase in the lignin
content
• Coconut husk is retted and the fibers are entangled by
beating.
• Coir fiber has various uses like making mats, carpets,
cordage, brushes etc.
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59. REFERENCE
• Cutter, E. (1978). Plant Anatomy Part I. Reading, Mass.: Addison-Wesley Pub. Co.
• Esau, K. (1965). Plant anatomy. Plant Anatomy., (2nd Edition).
• Fahn, A. (1977). Plant Anatomy. Oxford: Pergamon Press.
• Foster, A. (1949). Practical Plant Anatomy. New York: D. Van Nostrand Co.
• Pandey, B. (1996). Plant Anatomy. New Delhi: S Chand & Comp.
• Pandey, S. N., & Chadha, A. (2009). Plant anatomy and embryology. Vikas
Publishing House.
• Satyanarayana, K. G., Kulkarni, A. G., & Rohatgi, P. K. (1981). Structure and
properties of coir fibres. Proceedings of the Indian Academy of Sciences Section
C: Engineering Sciences, 4, 419-436.
• https://labs.plb.ucdavis.edu/rost/cotton/reproduction/frfiber.html
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60. THANKYOU