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Nephrolepis, Adiantum, Marsilea

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NEPHROLEPIS

Division FILICOPHYTA (PTEROPHYTA)


Class LEPTOSPORANGIOPSIDA

Order FILICALES

Family POLYPODIACEAE PINNA

Gegus NEPHROLEPIS
PETIOLE

-LEAFLETS

A portion of leaf
EPIDERMIS

CORTEX

ENDODERMIS

PERICYCLE
PROTOXYLEM
METAXYLEM
PHLOEM

T.S. of root
PETIOLE CUTICLE
EPIDERMIS
LEAF TRACE
SCLERENCHYMATOUS
HYPODERMIS

CORTEX

STOLON ENDODERMIS
PERICYCLE
RHIZOME
PROTOXYLEM
PITH
TUBER
METAXYLEM

PHLOEM
ROOT

Habit of plant body


( External features)

f.s. of rhizome
269

The genus includes about 30 NEPHROLEPIS


many gardens in India. The plants are species out of which 6-7 spccies arc
forests. mostly terrestrial but a few specics are commonly grown in
EXTERNAL FEATURES: epiphytic in tropical
1. The
2. The sporophytic plant body is diffcrentiated intoroot,
rhizome underground, grows crect (rarcly rhizome (stcm) and leaves.
is
from the tuber or from the oblique), short and wiry. It arises
scales. The scales are hairy. prothalli. It is covered closely by the petiole bases and
3. The rhizome gives 4-5 short,
tosome distances and produceslender lateral stolons, which creep on the substratum
new tufts of lcaves.
4. The stolons produce tufts of small röots,
which are adventitious. The roots may also
arise from stem (rhizome). A few species produce tubers at the end of stolons.
S. The plants produce 3-5 leaves cach year. The leaves are
long,
Compound. Rachis is long, slender and has a shallow groove on narrow and pinnately
the dorsal side.
6. Pinnae are oblong, alternate, pale-green with crenate margin. The venation is
The veinsare free usuallybear white lime dots at their tips. furcate.
7. The pitiole, rachis and pinnae are usuallycovered with scales.
INTERNAL FEATURES:
T.S. of root:
1. The outermost single layered epidermis consists of thin-walled cells.
2. The cortex is broad and parenchymatous.
3. Endodermis is single layered. Their tangential walls are suberized.
4. Pericycle is 1-2 layered consisting of thin-walled cells.
5. The stele issimple type of protostele (haplostcle) in which the central core of xylem
tracheids is surrounded by phloem and conjunctive parenchyma.
6. The xylem is diarch and exarch.
TS. of rhizome:
1. The outline of section is neary circular.
2. The outermost single layered epidcrmis consisls of narrow, quadrangular cells. The
epidermis is coated with cuticle.
3. The epidermis is followed by 1-2 layercd, thick-walled, sclerenchymatous
hypodermis (or outer cortex).
4. It is followed by a broad zone of inner cortex consisting of thin-walled
parenchymatous cells.
5. The central stele is surrounded by single layered endodermis followed by 1-2
layered pericycle.
6. The stele, in most of the parts of rhizome, is amphiphloic siphonostele but at the
apical part it becomes arudimentary type of dictyostele due to appearance of lcaf
traces.
7. The xylem is crescent shaped surroundedon both the sides by phloem, pericycle and
endodermis. The protoxylem lics at both the ends of crescent-shaped xylem. It is
exarch.
8. The centre i_ occupied by pith.
NEPHROLEPIS

CUTICLE FERTILE PINNA


-EPIDERMIS
SCLERENCHYMATOUS
HYPODERMIS

aA ENDODERMIS SORI
PERICYCLE
-METAXYLEM

-PROTOXYLEM
-PHLOEM

PARENCHYMATOUS
GROUND TISSUE

MERISTELE Single sporophyll showing sori

T.S. of petiole
SPOROPHYLL

SORUS

-RECEPTACLE
MATURE
SPORANGIUM
DEVELOPING SPORANGIUM
TRUE INDUSIUM

T.s. of sporophylM passing through sorus


Single sorus
APICAL NOTCH

-ANNULUS
ARCHEGONIA

CAPSULE

STOMIUM

ANTHERIDIA
-STALK
RHIZOID

Sngle sporanglum
A mature prothallus
271
TS. of petiole
1. The outline of
2. The section is nearly circular with a shallow
outermost single layered epidermis is coated with groove on dorsal siae.
3. It is followed by a thin zone of cuticle.
4. The central part is occupicd sclerenchymatous
by thin-wallcd,
about 3-6or morc meristcles are
hypodermis.ground
parcnchymalous
arrangcd in a horse-shoe like tissue n wntc
5. Each meristele has single layered endodermis curve.
The central xylem is crcscent shaped, which is (ollowcd by 1-2 layered pericyce.
and exarch. surrounded phloem. Xylem is darcn
by
SPOROPHYLL (The spore producing organ):
1. There is no differenc between a fertilc lcaf and a sterile leaf except for the
of sori. The fertile leaf, bearing sori on pinnac, is called prescnce
sporophyll.
2. The sporangia are borne in groups called sori, The sori are separate and borne intra
marg1nal or dorsalon the veins.
3. Each sorus is rounded or somewhat elongated having kidney-shaped or reniform
indusium.
T.S. of fertile pinna (sporophyll) passing through sorus :
1. The seclion shows usual internal structure of fern lamina,showing the sorus towards
the margins.
2. Each sorus contains a group bf about 1620 sporangia.
3. The sporangia lic mixed cn a raised fleshy receptacle, enclosed within an indusium.
4. The indusium is true, usuallyround or reniform (kidney shaped). It is attached by a
broad curved base.
5. AIlthe developmental stages of sporangia are seen in one sorus.
6. The mature sperangium is differentiatcd into stalk and body (the capsule).
7. Thestalk is long made up of 4- 5 cells. The capsule is oval or biconvex.
8. The capsule has single layered jacket. A few cclls of jacket are modified and form
stomium and annulus. The capsule encloses dark-coloured homosporous spores.
PROTHALLUS (The gametophyte) :
1, Themalure prothallus is light-green, cordate or heart-shaped and profusely hairy.
2. The central portion is thick and forms cushion. Many rhizoids arise from the lower
portion of ventral cushion. borne irst and the
3. The prothallus is hermaphrodite (bisexual). The antheridia are
archegonia later. posterior
4. The antheridia are small, sessile and projccting type. They lie towards the
side of ventral cushion.
5. The archegonia are borne onventral surface towards the apical notch,
apicalnotch.
6. The meristem lies deep in the
ADIANTUM
INDUSIUM
Division FILICOPHYTA (PTEROPHYTA )
Class LEPTOSPORANGIOPSIDA
Order FILICALES
Family POLYPODIACEAE
Genus ADIANTUM

VEINS

LEAFLETS A
Single leaflet leaflet showing reflexed
indusia

EPIDERMIS
ROOT HAIR
CORTEX

ENDODERMIS
PERICYCLE

PETIOLE
PHLOEM

CIRCINATELY COILED METAXYLEM


YOUNG LEAF
PROTOXYLEM

RHIZOME ROOT

Adiantum, Habit of plant body


Adiantum. T.S. of root

EPIDERMIS HAIR
MERISTELE
HYPODERMIS
GROUND TISSUE

ENDODERMIS
PERICYCLE
METAXYLEM
PROTOXYLEM
HAIR
PHLOEM
Adiantum. T.S. of rhizome (diagrammatic)
Adiantum T.S. of rhizome
(A part cellular)
273

ADIANTUM (Maiden-hair fern)


The genus Adintum includes about 200 Species. It is a terrestrial fern
mostly in the warmer parts in the word. wh iclh growS

EXTERNAL FEATURES :
1. The sporophytic plant body is differentiated into root, stem and leaves.
2. The stem (rhizome) may be long and creeping or short and ascending.
3. The adventitious roots arise from the lower side of rhizome.
4. The leaves are macrophyllous arise alternately or spirally on the rhizome. The
young lcaves are circinately coiled and slow growing.
5. Each leaf has a long, shining black and brittle petiole. Leaves are compound
and have dichotomously branched lamina which terminates into many leaflets.
6. The leaflets may be entire or branched. They show dichotomous venation
The mid-rib is abscnt.
7. All the young parts including rhizome are covered with hairs called ramenta.
INTERNAL FEATURES: T S. of rhizome (stem) :
1 The outline of section is slightly circular or gutter-shaped.
2. The outermost single laycred cpidermis bears multiccllular hairs.
3. The epidermis is followed by 2-3 layered, sclerenchymatous hypodermis.
tissue.
4. The major portion, next to hypodermis, is parenchymatous ground
5. Thestele varies from amphiphloicsiphonostele to dictyostele In 4. pedutum,
siphonostele. Most
where the rhizome is elongated, the stele is amphiphloicseveral meristeles arranged
commonly the stele appears to be brokenup into
in a ring. This type of stele is called dictyostele.
layered endoder
6. Each meristele is oval to elongated. It has outermost, single
mis followed by single layered pericyclc. It is surrounded
The xylem is located centrally. The protoxy lem is mesarch.
7. conditions are also seen.
by metaxylem. Sometimes other
by phloem.
8. The eentral solid core of xylem is surrounded
T.S. of root:
The outermost single layered piliferous layer is composed of thin walled, tange
1.
ntially elongated cells. It bears a few unicellular root hairs.
parenchymatous ce lls.
2. Thecortex is multilayered, consists of thin walled
3. Endodermis is single layercd followed by single layered pericycle.
Metaxylem lies in
core of xylem is surrounded by phloem.
The central solid
4. opposite sides of metaxylem.
the middle. Protoxylem groups are located on two
protostcle (haplostele).
5. The xylem is diarch and exarch. The stele is
T.S. of rnchis :
covered with cuticle.
1. The outermost single layer is epidermis which is
hypodermis.
2. It is followed by 3-4 laycrs of thick walled sclerenchymatous
parenchymatous cells.
3. The cortex is broad, consists of thin walled
The centre is occupied by a large protostele which is surrounded by single lay
4. layered.
ered endodermis. The pericycle is single
shaped. The protOxylem is exarch. The xylem
5. The xylem is triarch It is Yphloem.
is completely surrounded by
ADIANTUM
EPIDERMIS
HYPODERMIS

CORTEX

INDUSIUM
ENDODERMIS
LEAFLET
-PERICYCLE

PROTOXYLEM

METAXYLEM

STALK

PHLOEM
SPORANGIA
PLACENTA INDUSIUM

Adiantum. V.L S. of leaflet through reflexed


Adiantum T.S. of rachis lobe (Indusium) (diagrammatic)
VEIN
INDUSIUM
SORUS

PLACENTA,

STALK

SPORANGIA

Adiantum T.S. through indusium (diagrammatic)


Apex of leaflet showing
reflexed lobe (Indusium) YOUNG
LEAF
ANNULUS

APICAL
NOTCH

PROTHALLUS 4
~STOMIUM

ROOT
-STALK RHIZOIDS

Single sporangium Adiantum.Prothallus bearing young


sporophyte
275
T.S. of leaflet :
1. The section shows upper and lower epidermis. Both layers possess chloropl
asts. The lower epidermis is interrupted by stomata.
2. Inbetwcen the upper and lower epidermis the space is Alled with looscly arr
anged spongy parenchyma except at lower side where a compact layer of meso
phyll is present just above the lower epidermis.
3. The vascular bundles are surrounded by multilayered thik wailed sbeath.
4. Bach vascular bundle has single layer of endodermis followed by pericycle.
5. The stele is protostele consisting of xylem surrounded by phloem. The pro
toxylemfaces towards adaxial side of leafiet.
SPORE PRODUCING 0RGANS (sporophylla) :
1. The sporangia are borne in groups called sori. The sori are attached all
along the distal regions of separate veins on the inner face of indusium.
2. The margin of blade is folded towards the lower side and forms fake
indusium.
3. All the developmental stages of sporangia can be scen in a sorus.
V.LS of leaflet (spropbyll) through sorus :
side.
1 The section shows folded of reflexed distal margin on its lower
outgrowth which serves as
2. The sporangia are borne in groups on the cflexed
false indusium.
with spores.
Each sporangium has a long stalk and an oval capsule, illed
3.
sporangia :
T.S. of reflexed-lobe showing
1. The section shows
many vascular strands, cach corresponding to thegroup of
sporangia. capsule.
2.. Each sporangium
has a long, slender, multicellular stalk and an oblong Some
capsule has single of thin walled cells.
layered jacket which consistsform
3. The vertical row and auoulus, The cells of
cells of jacket arc arranged in a
tangential walls.
annulus show thickening in their radial and inner
which lies on one side of annulus,
4. Afew thin walled cells form a stomium
PROTHALLUS :
gametophytic plant body or prothallus is small, Aat, dorsiventral, leafy
1. The
and heart shaped.
central portion is thick whereas margins are one cell thick. The apical
The growing point is situated.
notch lies on the anterior end where the
2.
lower (ventral) surface.
Many unicellular rhizoids arise from the The
3.
Both antheridia and archegonia are formed on the same prohallus.
towards anter
4. whercas archegonia lie
antheridia lie towards posterior portion surlaco. They are protuding type.
ior portion near apical notch on ventral
Prothalluswith young sporophytes :
while enclosed within the gamctophyte.
1. The sporophytc grows out replaced with advcntitioås roots.
The root grows lirst which soon is circinately
2.
leaf emerges out through the apical notch. Tlie young leaf is
3 The
coiled but soon it expands.
MARSILEA
Division FILICOPHYTA (PTEROPHYTA )
Class LEAFLETS
LEPTOSPORANGIOPSIDA
Order MARSILEALES
Family MARSILEACEAE
Genus MARSILEA

CIRCINATELY COILED
YOUNG LEAF
PETIOLE

RHIZOME
(STEM)

VEINS

ROOT SPOROCARP

Single leaflet Marsilea Habit of plant body (External features )


AIR
CHAMBER
EPIDERMIS

AIR CHAMBER
OUTER.CORTEX
SEPTUM

INNER CORTEX
SEPTUM

ENDODERMIS
-PERICYCLE
PROTOXYLEM

METAXYLEM PHLOEM

Marsilea.T.S. of root (A part cellular)

PHLOEM

Marsilea T.S. of root (diagrammatic)


MARSILEA
The genus Marsilea includes about
orted irom India. Most of the species are 65 species out of which only 11 have been roP
puddles after the rains (e.g., M. minutd, M.aguatic. grow in temporary ponds, pools and
Quadrifia, M. aegypticu, etc.).A tew ure
amphibious.
on dry soil.
M. hirsuta, M. rajasthanensis, M. condensata, etc., are xeropbyie auu
EXTERNAL FEATURES :
1. The sporphytic plant body is differentiated into stem (modiied into rhizome),
root and leaves.
2. The stem is modified in the form of creeping rhizome. It is slender and bran
ched and has indefinite growth. The rhizome grows horizontally ust beloW
the surface of soil.
3 The stem (rhizome) is divided into nodes and internodes. The leaves and
roots arise from the nodes.
4. The roots are adventitious and arise in acropetal succession from cach node.
5. The leaves arise from nodes in acropetal succession (i.e., youngest at the
apex of rhizome). They are arranged alternately ia two lateral rows on the
upper side of rhizome.
6. Each yoUng leaf is circinately coiled. The young leaves, in some species, are
covered by unbranched mult icellular hairs (e.g., M. minuta).
7. divided into 4equal
The leaves are compound and petiolate. The laminatheis other
leafiets or pinnae. The two form distal pair and twJ form the
proximal pair.
8. The petioles of plants growing in water are extremely long, weak and flexible.
They help the leaflets to float on water surface. The same plant when grows
on soil or mud shows short, stout and erect petioles.
9.
They are once or twice deeply
The leaflets are obovate to nearly elliptical. margin
lobed, wedge shaped with smooth or toothed and show dichotomously
branched venation.
10. The leaflets show sleeping
movements at night (i.e., they are folded upward at
night). Each
Thesporangia are borne ioside the fruiting bodies called sporocarps. borne
11
SDorocarporiginates laterally from petiole near the base. They may be
singly or in groups (1-4).
INTERNAL FEATURES (ANATOMY):
root :
(i) Root: T.S. of nearly circular.
1. The outline of section is tangentially elongated thin
2. The outermost single layered epidermis consists of
walled cells.
The. epidermis is followed by cortex which is differentiated into two zones.
3.
cortex consists of large air chambers separated by radial septa. The
Outer side
inner cortex is parenchymatous. In some cases the cells towards inner
may become thick walled.
4. Endodermis is single layered followed by single layered pericycle. exarch xylem
5. The stele is protostele consisting of central, plate-like, diarch and
surrounded on both the sides by phloem.
MARSILEA
SEPTUM
EPIDERMIS
SEPTUM
AIR CHAMBER

OUTER CORTEX

MIDDLE CORTEX

-INNER CORTEX
-OUTER ENDODERMIS
OUTER PERICYCLE
OUTER PHLOEM
XYLEM
INNER PHLOEM

INNER PERICYCLE
PITH INNER ENDODERMIS

PITH
Marsilea, T.S. of rhizome (diagrammatic)

A.S. of rhizome (A part cellular)


EPIDERMIS
SEPTUM
AIRCHAMBER SEPTUM

OUTER CORTEX
INNER CORTEX

ENDODERMIS
PERICYCLE

PROTOXYLEM
METAXYLEM
PHLOEM

Marsilea. TS. of petiole (diagrammatic)

T.S. of petiole (A part


cellular)
PTER0DOPEYTA
279
Ait) Rhizome (stem): T.S. of
outline of section hizome
1. The :
2.
is circular.
The outer most single layered epidermis is
3. The cortex is several layered thick. It is continuousand without stomata.
cortex, middle cortex and inner cortex. diferentiated into three zones-ourer
4. The outer cortex consists of outer compact,
Cells thCk porton lolloved hy larye air spaces. parenchymatous, one to severai
The air spaces (lacunac) are
separated with each other by septa. This tissue is called
S. The middle cortex is few layered çonsists of thick walled aerenchyma.
6. sclerenchymatous ceils.
The inner cortex is compact, parenchymatous cells containing
7. starch grains.
Scattered in the outer and inner cortex are few tannin cells.
8. The stele is amphiphloic siphonostele
9. (solenostele).
Ihe centre is occuzied by pith which may be parenchymatous (in submerged
species) or sclerenchymatous (in plants growing in dry habitat).
10. There is external as .well as internal endodermis. The outer endodermis is
followed by single layered outer pericycle.
11. The xylem is in the form of a ring whtch is surrounded on both the sides by
outer and inner phloem.
12. The inner phloem is followed by inner pericycle and ianer endodermis.
13. The protoxylem inay be distinct or illdefined. It is exarch or mesarch.
Special features :
1. Presence of large air spaces in the outer cortex (hydrophytic character).
2. Presence of sclerenchymatous middle cortex and pith (xerophytic characters).
3. Stele is amphiphloic iphonstele (solenostele).
Leaf
T.S. of petiole :
1. Outline of section is circular. rectangular cells.
2. Outermost single layered epi dermis consists of into outer and inner cortex.
3. It is followed by cortex which is differentiated
The outer cortex (hypodermis) is parenchymatous (aerenchymatous). It consists
4.
of large air chambers separated by septa or trabeculae.
5. The inner cortex is compact parenchymatous. Scattered in this region are
few starch cells and tannin cells.
6. The stele is more or less triangular. It is protostele.
7. Bndodermis is single layered followed by single layered pericyce. way that they
V shaped strands arranged in such a
8. The xylem consists of two
look Y shaped when seen together. two tracheids in the middle and smaller
9. Each xylem strand has larger one orprotoxylem is exarch.
tracheids at either ends. Thus, the
10. The xylem is surrounded by phloem.
T.S. of leaffet :
1. Theleaflet shows upper and lower epidermis. the surfaces but in foating leaves
2. The stomata are generally present on both
they are found only on upper epidermis. and lower spongy parenchyma.
3 The mesophyll consists of upper palisade transverse septa.
4. The spongy parenchyma has large air chambers separated bybundle consists of
vascular
5. The vascular bund les are concentric type. Each
by phloem.
central xylem surroundedenclosed
The vascular bundles are within endodermis and pericycle.
6
MARSILEA

GELATINOUS RING
V.T.S.
MICROSPORANGIUM
DORSAL BUNDLE MEGASPORANGIUM
LATERAL
-GELATINOUS RING BUNDLE
H.L.S.
MICROSPORANGIUM
MEGASPORANGIUM
LATERAL BUNDLE
PLACENTAL BUNDLE

PLACENTAL BRANCH
SORUS
STALK
INDUSIUM BUNDLE SPOROCARP
SORUS WALL
INDUSIUM
GELATINOUS RING Marsilea, H.L.S. of sporocarp STO MATA
SPOROCARP WALL
Marsilea. V.T.S. of sporocarp EPIDERMIS

TUBERCLES HYPODERMIS

RAPHE BODY

STALK Wall of sporocarp

External features of sporocarp

MICROSPORANGIUM
MEGA
GELATINOUS SORUS GELATINOUS
RING RING SPORANGIUM
INDUSIUM
V.L S. SORUS

RECEPTACLE

olo .".

STALK

SPOROCARP
WALL
RECEPTACLE SPOROCARP
INDUSIUM
WALL

Marsilea . V.L S. of sporocarp passing through Marsilea. V.L S. of sporocarp passing thrcugh
micro sporangia mega sporangia
PIHDOPYTA
281
THE SPOROCARP
Erteral features:
1. Ine
sporocarps are the spore producing organs which are borne laterally on
the adaxial side of the petiole.
Bach sporocarp consists of a stalk (peduncle) and a body.
3. The body of sporocarp is bean-shaped or ovoid. The place where stalk and
body meet is called raphe.
4.
The
cles sporocarp,
on its dorsalbeyond
side. the raphe, bears two projections called teeth or tuber
S. The lower tubercle is stout and prominent whereas thèupper one is more
slender and delicate.
6. ThesporOcarp is green in the begining but when matures, it turns brown.
7. Marsilia is heterosporous and therefore, both megasporangia and microsporan
gia are enclosed within the sporocarp.
Internal features :
VT.S. of sporocarp :
1 The wall of sporocarp consists of three layers.
2 Outer single layered epidermis shows the presence of stomata.
3. Ioner two layers of hypodermis consist of radially elongated cells (palisade).
The uppcr hypodermal layer has thick walled cells whereas lower layer has thin
walled cells. The nuclei in hypodermal cells are arranged in one ine.
4 The receptales are cut longitudinally. Thus, only two sori are seen in this section.
5 Each sorus is covered by its own two layered indusium.
6 In side the sorus, the microsporangia are seen at the corners whereas the mega
sporangia are attached all along the recepticular ridge.
7. There are two masses of gelatinous rings, one on either side of the section.
The upper ring is bigger than the lower.
8.
Dorsal bundle, lateral bundle, placental bundle and placental branches are
Seen in this section.
V.L.S. of sporocarp :
The outer wall consists of three layers--the outermost single layered epidermis
J. hypodermis (palisade).
with stomata and inner two layered
2. The wall is followed by the gelatinous ring which surrounds the sori.
3. The sori are cut longitudinally and they are arranged in a row, If the section
is nassed somewhat to one side of the median line only megasporangia are seen
inside the sori.
Ifthe section passes away from the median line, only microsporangia are seen
4.
arranged on either sidc of the receptacle.
The stalk bundle and cut lateral bundles are seen in this section.
H.LS. (Horizontal longitudinal section) of sporocarp :
1.
The stalk of sporocarp is cut transversely that shows the presence of stalk
bundle.
The outer wall consists of three layers-single layered epidermis with stomata
2.
and two layered
Gelatinous
hypodermis consisting of radially clongated cells.
rings are seen only on two sides i.e., on dorsal and ventral sides.
3.
The one on the dorsal side is larger than that on the ventral side.
4. Allthe sori of sporangium are cut transversely in this section. They are arran
ged in two rows. The soriof two halves alternate with cach other.
5 Each sorus is coverved by its own indusium. The sorus shows megasporangium
located cenrally and microsporangia on either side of the receptacle.
6. Lateral bundles are cut transversely. The dorsal bundle, lateral branches and
recepticular branches are seen in thËs section.

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