Morphology anatomy and reproduction in Gnetum

Davanagere University
Department of Botany
Seminar Topic: Morphology, anatomy and reproduction of Gnetum
Presented by :
S K SACHIN
1st
year Msc
1st
semester
Under the Guidance
Dr.MANASA D.J
Assistant Professor
Department of Botany
Davangere University

Content:
Introduction
Morphology and anatomy of root
Morphology and anatomy of stem
Morphology and anatomy of leaf
 Reproduction in Gnetum
Male reproductive structure
Female reproductive structure
Economic importance
conclusion
 Reference

Introduction:
Gnetum is plant are similar to the dicot plant. Distribution of Gnetum in 40 to
50 species in world.
Habit: woodyclimbers , some shrub’s or tree
The Gnetum sporophytic body is differentiated into Root ,Stem, Leaves.
In the gentum 2 types branches like as 1) Branches limited growth
. 2) Branches unlimited growth
Leaves are simple , decussate,Broad (large) , evergreen,
ovule with entire margins.
Leaves arranged decussate fashion with reticulate venation.
Retulate venation: the arrangement of veins leaf where they from weblike
structure

Decussate: opposite leaves arranged with each succeeding pair at right
angles to the pairs below and above them.
 5 species of Gnetum are found in India mainly distribution tropical regions.
Like as :
1) Gnetum gnemon : small tree or shrub with small branches.
Assam , Manipur,Arunachal Pradeshl.
>2) Gnetum montanum: woody climbers . occur Assam , Manipur ,Sikkim .
> 3) Gnetum latifolium : Evergreen shrub or climber species is mainly
distributed in Andaman and Nicobar islands.
> 4) Gnetum contractum : it is shrub occurs in Kerala .
> 5)Gnetum ula : woody climbers , swollen nodes the occurs in eastern and
western ghats.

Gnetum gnemon
Gnetum latifolium
Gnetum ula
Gnetum montanum

Morphology and anatomy of Root :
Morphology of root:
> The usely taproot branches .
Secondary advantious roots are present.
Anatomy of root :
Epidermis single layered root hair present.
Cortex : many layered perenchymatous with
starch grains few fibre cells are present.
Endodermis and pericycle are in many
layered.
Metaxylum towards centre and protoxylum
towards periphery .

Secondray growth is present in
Gnetum root .
Roots are diarch and exarch condition
in the vascular bundles.
Exarch : arrangement of xylem tissue
in which protoxylem towards the
periphery and metaxylem towards the
centre.
Diarch : Diarch condition 2 vascular
bundles or xylem present in dicot root .

Morphology and anatomy of Stem :
Morphology of Stem :
Gnetum stem is elongated and dicot .
Stem is node and internode are present.
2 types of shoot like as:
. 1) short shoot : limited growth .
2) Long shoot: unlimited growth.
Anatomy of stem :
The Cuticle is thick covered with epidermal
unicellar layer.
Sunken stomata are present.
The Cortex is elongated with many layer like
chlorenchymatous ,parenchymatous and
schlerenchymatous cells .

Endodermis and pericycle indistingiushable .
Vascular bundle is separated by
parenchymatous cells with one another.
The vascular bundles are conjoint.
The cambium in present and separated by
vascular bundles to the xylem and phloem .
Xylem consists of xylem vessels, tracheid.
Phloem consists of sieve tube and phloem
parenchyma.
In the pith contains parenchymatous and
laticiferous cells present.

Morphology and anatomy of leaf:
Morphology of leaf :
Leaves are simple broad (large) .
Leaves ovule and entire margins.
Leaves are decussate fashion and reticulate
venation.
Decussate : leaves arranged opposite to each
other.
Anatomy of leaf :
Leaves similar to dicot.
Cuticle covering with epidermis.
Stomata are present.
Palisade mesophyll and spongy mesophyll
are present and it’s contains chloroplast.

vascular bundle are present and curve or
(Arc) form in the midrib region.
Vascular bundle are conjoint.
In the vascular bundle xylem and phloem
is present.
In the xylem consists of tracheid , vessels
xylem parenchyma.
In the phloem consists sieve cell and
phloem parenchyma are present
Middle portion cambium is present.

Reproduction in Gnetum:
Gnetum is dioecious and cones / strobili
reproductive stature .
The Gnetum strobili/ cones organised into
inflorescence or panicle and terminal
position.
The cone axis are node and internode
present.
Whorl of circular bracts are present at node.
Flower present these collars upper few collars
may be reduced and sterile in nature.
 cupule Are present in the nodal region.

Male reproductive structure:
Male reproductive organs Gnetum is male cone/
strobili.
Male cone / strobili show the node and internode.
Each node more number of whorl like structure present
called male flower .
Male flower at the part abortive ovule present Gnetum
of male reproductive system.
Above these abortive ovule male flower are arranged
in a whorl like stature .
All male flower protected by cover or coat or cup like
like structure called cupule.

In this cupule is transparent layer protected to male
reproductive organs young age to adult age .
In male reproductive organs above the perianth
dithicous anthers present.

Female reproductive structure :
Female reproductive organs Gnetum called female
strobili /cone .
Female strobili devloped female plant in terminal part of
the shoot.
In the female cones are present in node and internode
present
Each node more number of ovule devloped in whoral
like stature.
These ovule are protected by coat or cup like stature
called cupule .
Below the cupule more number of ovules present and
developed these ovule called as female flowers.
**********************

Structure OF OVULE:
The ovule represent female flower.
The ovule stalk in some Gnetum species , sessile or
subsessile.
In that ovule massive nucellur tissue made up .
The ovule protected by 3 envelopes or integument
as outer ,inner, middle envelopes.
> Inner envelop or integument elongated to form long
micropylar tube
Inner integuments free from nucellus except to
chalazal end
All 3 envelop .of ovule develop in acropetal manner.
In the pollen chamber is present at tip of nucellus .

Economic importance of Gnetum:
Young leaves and inflorescence of Gnetum gnemon and Gnetum latifolium
are cooking vegetable.
Seed of Gnetum gnemon , Gnetum latifolium, and Gnetum ula eaten after
. Boiling sometimes they are fried in oil and eaten.
G.gnemon, G.latifolium used to ropes prepared from this fiber are light
strong.
G.montanum Possesses pesticidal properties.

Conclusion
Gnetum plants are gymnosperms they produce seed but not enclosed in a
fruit.
They typically have broad leaves and found in tropical region.
They evergreen plant and small shrub ,tree and some climbers.
The sporophytic plant is easily differentiated into Root , stem, leaves.
The Gnetum stem ,leaf is resembles to dicot type .

Reference
1.B.P. PANDEY, College Botany, S.Chand publication,1979
. Pg no: 121- 161
2.A.V.S.S.SAMBAMURTY ,A Text book of Bryophytes ,pteridophytes,
Gymnosperm and paleobotany, I .K International publication, 2005
. Pg no: 396-418.
. ***********************

Morphology anatomy and reproduction in Gnetum

Morphology anatomy and reproduction in Gnetum

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