This slideshow is in accordance to B.Sc II (Medical) syllabus (Panjab University)

1. 1
Gymnosperms and their
Economic Importance
Dr Jasmine Brar
Email : drjasmine1807@gmail.com

2. Stem is erect, unbranched woody. Leaf scars show their
characteristics in the stem.
Leaves may be monomorphic or dimorphic.
Two kinds of dimorphic leaves are:
a. Foliage leaves which are evergreen, simple or
compound.
b. Scale leaves which are minute & deciduous
Pinnately compound leaves eg. Cycas; needles in Pinus;
Scales in Ephedra 2

3. Vasculature of roots varies from diarch to polyarch.
Vascular bundles in stem are collateral, endarch, open
& arranged in rings.
Secondary growth is well marked with distinct annual
rings but in Cycas, cambium is short lived & hence
formation of well developed cortex, pith & parenchyma
rays (manoxylic wood).
In Pinus, pith & cortex are quite reduced & parenchyma
rays are few (pycnoxylic wood) which is densely packed.
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4. Foliage leaves are well protected by thick layer of cuticle
or waxy layer.
Stomata lie in sunken cavities (xerophytic character)
Xylem is mesarch (protoxylem develops first in the centre
& continues to develop both centrifugally & centripetally)
Transfusion tissue (helps in conduction)is the
characteristic feature of gymnosperm leaf.
Reproductive organs are aggregated to form compact
cones or strobili (cones may be either male or female &
rarely bisporangiate)
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5. Male & female cones are homologus to male & female
flowers that bears microsporophylls (stamens) &
Megasporophylls (carpels) which are arranged on an
elongated axis : thalamus
Cones (flowers) are without perianth (except Gnetum &
Ephedra where scale like perianth occurs)
Female cones are larger than male cones (except Cycas)
Male cones are short lived. Microsporophylls are flat
In Cycas or peltate in Pinus.
Feamle cones are long lived & remain attached to plant
for several years for maturity & ripening of seeds.
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6. Microsporangia or pollen sacs are borne on abaxial or
Morphologically lower surface of microsporophyll.
They may be many & grouped in form of sori like ferns.
Eg. Cycas & reduced to two in Pinus.
Megasporangia or ovules are borne naked on the
sporophyll. Ovules are orthotropus & covered by
single integument.
Integument surrounds nucellus which is differentiated
Into outer sarcotesta, inner fleshy sarcotesta & middle
stony sclerotesta. 6

7. Plants are heterosporous & form two types of spores.
Gametophytic generation arises by germination of spores
& is highly reduced.
Male gametophyte has either 1 or 2 prothallial cells: 1 in
Cycas & 2 in Pinus.
Pollen tube act as haustorium in Cycas & sperm carrier
in Pinus.
Female gametophyte bears variable number of archegonia.
There is no archegonia in Gnetum, Pinus has 2 archegonia
while Cycas has many archegonia.
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8. Each archegonium has an egg & a venter canal cell.
Neck canal cells are absent.
Pollination is anemophilous & pollen grains are deposited
in pollen chamber where they germinate.
Diploid zygote is formed by the fusion of male & female
nuclei.
Development of zygote is meroblastic where only basal
part develops into an embryo, upper part develops into
haustoria & middle part forms suspensor. 8

9. There is development of many embryos in one seed ie.
exhibit polyembryony.
Embryo is differentiated into roots, stem & leaves.
Embryo is endoscopic where plumule is directed away
from micropyle & radicle towards the micropyle.
Endosperm is food laden tissue & develops before
fertilization in gymnosperms.
Embryo is developed at the end of long suspensor which
is pushed down to endosperm. 9

10. Food present in nucellus is absorbed by female
gametophyte to form endosperm so endosperm is haploid
& is formed before fertilization.
No double fertilization/triple fusion is there so endosperm is
haploid, (n) (triploid, 3n in angiosperms).
Except a small part called perisperm, whole of nucellus is
crushed. Perisperm persists in the seed in the form of a
narrow film or cap.
Since, ovary is absent, so seeds are naked & fruits are not
formed in gymnosperms. 10

11. Middle sclerotesta which is stony layer of integument
Becomes very hard & give protection to female
gametophyte & embryo.
Number of cotyledons vary from 1-2 in Cycas to many
whorls in Pinus.
Seeds may remain dormant for sometime or immediately
germinate without any resting period.
Radicle of seed grows downward & develops primary tap
root while plumule grows upright & develops stem.
The stem has unlimited growth, rarely it is limited
eg. Welwitschia
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12. Sporophytic generation is dominant & independent while
gametophytic generation is highly reduced & is dependent.
Economic Importance of Gymnosperms
Wood: They are most important as source of wood &
Constitute major forest wealth.
Wood is light coloured, straight grained & light weight.
The strongest Indian coniferous wood is used for making
Railway slippers is deodar wood obtained from Cedrus
Deodara. The heart wood of this tree is resistant to insect/
fungus attacks & has strong scent.
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13. Resins: They are derived from conifers by tapping & used
in varnishes & paints eg. Copal obtained from Agathis.
Rosin: Type of resin obtained as a residue after the
distillation of pine oleoresin. It is used in paper sizing,
varnish making, enamels & preparation of plasters &
ointments.
Canada balsam: Abies balsamea
This resin does not crystallize on drying & has high
refractive index as of glass & used as mounting material
for microscopy & cement for lenses in optical work
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14. Sandrac : Callitris
Used for metal, paper & leather varnish. It is used in
modern pharmaceutical as pill varnish.
Many essential oils are obtained from coniferous species
which are used in perfumery & medicines.
Most imp. Oil is turpentine oil which is obtained from
Pinus spp. In metallurgy it is used in floatation process
for separating minerals from their ores.
Oil of Hemlock is obtained from Tsuga canadensis is used
as deodorants.
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15. Amber (Pinus succinifera)
is fossil resin used in making beads & jewellery.
Fatty oils: Fleshy outer layer of seeds of Macrozamia,
Torreya nucifera, Cephalotaxus drupacea. Gnetum ula also
yield oil used for illumination.
Paper: Pinus roxburghii, Abies pindrow, Picea smithiana,
Cryptomeria japonica supply wood pulp from which paper
is made.
Food:Very important of starch food. Sago (stem & seeds of
Cycas) used as poor man’s food
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16. Young shoots of C. pectinata are eaten by tribal people
of Assam.
Chilgoza (Pinus geradiana) yield edible seeds
Strobili of G. gnemon is cooked as vegetable
Medicines: Seeds, megasporophylls & bark of Cycas
are mixed with coconut oil & applied on sores&
wounds.
Ephedrine is extracted from E. intermedia, E.
geradiana used in treatment of Asthma, hay fever &
common cold. 16

17. Fiber: Bark of Gnetum gnemon & G. latifolium yield
fibres of high tensile strength used for making ropes
& fishing nets.
Poisons: Gnetum latifolium & G. contractum are used as
fish poisons. Pollen grains of Cycas circinalis have narcotic
properties. Taxus bacata is used as fish poison due to
presence of an alkaloid toxin
Medicines: Juice from young leaves of Cycas circinalis
used to cure stomach disorders, vomiting & skin diseases.
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18. Medicines: The seeds of Taxus bacata are used as
sedatives.
Fuel: The rhizomes of Ephedra gerardiana are used as
fuels. The wood & female cones of Pinus insularis are
used as fuel.
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19. Tanin: The bark of Sequoia sempervirens, Araucaria,
Picea, Dacrydium conatins good quality of tannin
which is used in tannin industry.
Laundary: Starch obtained from Macrozamia seed is
used for laundary purposes
Perfumes & Scent: Juniperous spp. are burnt as
incense in the temples.
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20. Funeral wreaths: The leaves of Cycas being strong &
leathery & remain green for very long time after being
cut from the plant & hence used by Europeans in funeral
wreaths.
Ornamentals: Many spp. of Cycas are grown in gardens
for decorative purposes
Thuja plicata, Juniperous, Biota orientals, araucaria
Miscellaneous Uses: The leaves of Cycas circinalis are
used for making brooms & baskets.
Stems of Cycas rumphii are used for making houses in
Indonesia
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21. Religious Plant: Ginkgo biloba (Maiden hair tree)
is grown in temples of China & Japan &is
worshipped
Healthy Climate: Conifers provide a cool &
soothing climate. They are planted in many health
resorts & sanatorias where patients go for
recreation & treatment.
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22. Angiosperms Gymnosperms
They may be trees, shrubs &
herbs
Mostly woody
They may be annuals,
biennials & perennials
Perennials
Xylem vessels & companion
cells are present
(-) except Gnetales
Bisexual flowers Unisexual cones
Ovules enclosed within
ovary wall
Ovules are naked
Flowers has ovary, style &
stigma
(-)
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23. Angiosperms Gymnosperms
Archegonia are absent in female
gametophyte
(+) except Gnetum
Vegetative reproduction is very
common
(-) except Cycas by
bulbils
No prothallial cells are formed in
germinating male gametophytes
(+)
Pollination is anemophilous,
entomophilous & zoophilous
anemophilous
Pollen grains fall on stigma,
travel through style & reach
ovary& ovule
Pollen grains directly
settle on micropyle during
pollination
Endosperm formed after
fertilization is triploid
Endosperm formed before
fertilization is haploid
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24. Angiosperms Gymnosperms
There is no cleavage
polyembryony
Cleavage polyembryony
is present
There is no free nuclear division
in Angiosperms
In zygote
Seeds are enclosed in ovary or
carpel. Ovary develops into
fruits & seeds are enclosed
within fruits. Hence name
Angiosperms (covered fruits)
No ovary is there so
seeds remain naked.
Hence, name
gymnosperms-naked
seeds.
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25. Manoxylic wood Pycnoxylic wood
It is porous, soft & has more
broad prenchymatous
medullary rays
Compact & has narrow
medullary rays
Commercially useless Great commercial use
It is found in Cycadophyta It is found in Coniferophyta
Eg. Cycas Eg. Pinus
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