Gymnosperm-Cycas | uksir-notes | Diversity-Living-World8
Diversity in Living World 8
 |
| Gymnosperm |
Want to know about Bryophyte, Click the Link below:
https://uksirnotes.blogspot.com/2022/10/Pteridophyta-Fern-Dryopterisuksir-notes.htmlWant to know about Kingdom of Plantae Algae , Click the Link below:
https://uksirnotes.blogspot.com/2022/09/Kingdom-Plantae-Algae-Spirogyra-uksir.html
GYMNOSPERM:
·
Naked seeded flowering plants.
·
1st true seed plants.
·
These are Phanerogams without ovary.
·
Term Gymnosperm was coined by –
Theophrastus.
·
Worldwide distributed. mostly in
temperate region.
·
Main plant is Sporophyte (2n)
·
Contain true Root, Stem and Leaf.
·
Tap root well developed, with vascular system.
·
In root symbiotic association can be
found- in Coralloid root of Cycasalgae found, in Root of Pinus Mycorrhizae
or Fungal association can be seen.
·
Stem- erect, branched or unbranched,
woody with leaf scar.
·
Contain endarch, collateral and open
vascular bundles.
·
Leaf- dimorphic
·
Foliage leaf- green, simple, pinnately
compound or needle shape or fan shape, with thick cuticle and sunken stomata.
·
Scaly leaf- Minute, deciduous,
protective.
·
In conducting tissue- xylem donot
contain Vessel and Phloem lack companion cell.
·
Wood- Monoxylic or pycnoxylic.
·
Heterosporous nature- Micro spore and
Mega spore found.
·
Micro spore- form male gamete i.e.in
side Pollen grain.
·
Megaspore- form female part.
·
Ovule or mega sporangia contain
Archegonium inside which Egg(n) found.
·
Ovary absent, for which fruit cant
seen.
·
Fertilization- siphonogamous.
·
Fertilization- forms Zygote (2n) which
form Embryo in side seed.
Seed again germinate to form new plant.
Classification:
 |
| Gymnosperm-classification |
a)
Cycadopsida:
(Cycads) Living and extinct forms.
Xerophytic, Palm like plant with large
compound leaves, Dioecious (Male female separate plant). Eg- Cycas,
Zamia, Extinct- Lyginopteris, Cycadeoidea etc.
b)
Coniferopsida:
(Conifers) Both extinct and living (more
the 500 sp)
Conical canopy, colder habitat. Aromatic,
antiseptic semi fluid resin canals present. Eg: Pinus, Ginkgo biloba, Cedrus, Abies etc.
c)
Gnetopsida:
(resemble angiosperm) Climbing shrub,
shrub and tree, well developed flower in whorl. Eg: Gnetum, Ephedra etc.
Economic Importance
:
Food Value
- Gymnosperms are used in the production of sago. Also eaten as green leafy vegetables.
Source of Oil
- Red cedar oil, extracted from Juniperus virginiana, is used to
clean very small objects and oil-soaked lenses.
- Oils extracted from Cyptomeria, Cedrus deodara, Cupressus, japonica,
and serum-Peruvians are used in perfume preparation.
- The oil extracted from the seeds of C. revoluta, macrozamia
riedlei, pinus cembra, and Cephalotaxus
drupacea is used as edible oils.
Timber Value
Gymnosperms are widely used in the making of furniture and for other construction purposes. E.g. Pinus.
Medicinal Value
Gymnosperms are widely used to treat infectious diseases and
other allergies including colds, coughs, asthma, respiratory
congestion, etc.
- Taxus is a type of coniferous tree known as drug
taxol. (anti-cancer drug)
- Cycas plants are used to treat many diseases and in the
production of various products related to hair care, including shampoo,
oil, lotion, etc.
Industrial Value
- Cycas gum is used as an adjuvant to medicine, a
remedy for snake bites, etc.
- Tannins extracted from Araucaria, Pinus, Sequoia,
etc., are used in the leather industry.
- Plywood prepared from podocarpus.
- Papers are prepared from the wood pulp of Pinus, Picea,
Abeis, Gnetum, etc.
Ornamental Value
- Several species of Cycas are widely cultivated as garden plants and
for decorative purposes.
- Ginkgo is planted as an ornamental plant in Chinese and
Japanese temples and is worshipped.
Some other
uses:
- Various species of gymnosperms help to produce medicines to
treat ulcers.
Cycads leaves are used in the production of hand baskets, hats, brooms, door and floor mats, and other eco-friendly products.
Cycas:
Systematic Position:
-
Kng- Plantae
-
Div- Gymnoperm
-
Cls- Cycadopsida
-
Ord- Cycadales
-
Fam- Cycadaceae
-
Genus- Cycas
 |
| Cycas |
General Character:
·
Evergreen, Palm like plant.
·
It is one medium size plant. Can be
upto 5 m.
·
Found in Australia and India (Bengal,
Odisha, Chennai, Assam etc.)
·
Plant body is Sporophytic (2n).
·
Contain- Root, Leaf and Stem.
·
Roots: Present at base of stem
·
2 types of root found- Tap root and
Coralloid root.
·
Tap root- Main root system, Absorb
water.
·
Coralloid root- Apogeotropic, comes
out of soil, looks Bluish – green. Anabaena BGA present in it.
·
Stem: Unbranched,
Columnar, Cylindrical, well developed Vascular bundle, Conjoint, Collateral and
Open type, Polyxylic, secondary growth
occurs, Very slow growth, Older part covered with leaf base.
·
Leaves: Diamorphic,
i.e Foliage and Scale leaves present.
·
Foliage leaves- long,
Pinnately Compound, Rachis contain 80- 100 pairs of leaflets or pinnae, apex
spiny, deep green, young leaf- circinate vernation.
·
Scaly leaves are protective, triangular,
small brown, dry, non-photosynthetic, covered by Hairy Ramenta.
Reproduction:
·
Vegetative and sexual reproduction
occurs
·
Vegetative Reproduction- by
Bulbils(adventitious buds)
·
Sexual Reproduction- advanced, with
well-developed system.
·
Plants Mostly Dioecious.
·
Sex organs develop- Called cone/
strobili.
Male and female cone born on separate sporophyte.
·
Antherozoids released inside Egg
apparatus, they swim to egg, but only one can fuse.
·
Fertilization leads to formation of
Zygote (2n).
·
Zygote is the 1st cell of
Sporophyte plant body.
·
Zygote develop to Pro- embryo, and
ultimately to a mature embryo.
·
2- 8 embryos may develop, but only one
survives.
·
The ovule becomes hard and develops to a Seed,
which contain embryo inside it.
·
The seeds are sweet in taste, pleasant
smell, can dispersed away by birds.
·
Under favorable condition they again
germinate to New sporophyte of Cycas.
·
Germination of seed is Hypogeal
(cotyledon remain inside soil)
Economic importance-
Ornamental look (used in garden), Sago extracted from stem pith (also called sago palm), Animal fodder, young leaf used as edible leaf, in skin disease, blood vomiting, stomach disorder etc
 |
| Life-cycle-cycas |
 |
| Pinus |
Want to know about Bryophyte, Click the Link below:
Want to know about Kingdom of Plantae Algae , Click the Link below:
https://uksirnotes.blogspot.com/2022/09/Kingdom-Plantae-Algae-Spirogyra-uksir.html
No comments