economic importance of gymnosperms assignment

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Economic Importance of Gymnosperms

An Overview

Based on the production of flowers, plants are classified into Angiosperms and gymnosperms. Plants that bear flowers are called flowering plants or Angiosperms. Plants that do not bear any flowers throughout their life cycle are called non-flowering plants or gymnosperms.

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Gymnosperms

Gymnosperms are other types of both vascular and non-vascular plants of the Kingdom Plantae , which directly produce seeds (naked) without bearing any flowers. Compared to the angiosperms, there are very few species of gymnosperms. These non-flowering plants species are abundantly found both in the colder region, boreal and temperate forests. They are evergreen plants, which can survive in any variety of habitats. In these plants, reproduction can be accomplished both by sexual or asexual reproduction.

Compared to angiosperms, the gymnosperms plant species are very few in number. This is mainly because they produce naked seeds, which are damaged by birds, animals, and other environmental factors before they are released. For the seed dispersal and continuity of the life cycle, they undergo wind pollination. Some of the best examples of gymnosperms are pine, cypress, larix, redwood, cycads, juniper, fir, etc.

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Now, let’s look at the economic importance of Gymnosperms

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Importance of Gymnosperms

• Gymnosperms are a good source of food. Seeds of these non-flowering plants are widely used as an edible species, used for producing various food products. These plant species include: ginko, pinus, cycas, etc.
• A few species of gymnosperms are a good source of starch and are also used in the production of sago. It serves as major staple food for lowland or indigenous peoples.
• In certain parts of America and in other lowland regions, the leaves of these plant species are soaked and eaten as a green leafy vegetable.
• The different species of non- flowering plants are widely used in the production of wine and also on other food products.
• Other than the food, gymnosperms are widely used by the pharmaceutical industry for the production of various medicines, which are effectively used to treat infectious disease and other allergies including cold, cough, asthma, bronchitis, etc.
• Taxus, a genus of coniferous trees is well known for the drug taxol. This is an anticancer drug, which is used in the treatment of different cancers and is prepared from the bark of the Taxus tree.
• Different species of Cycas plants are used in the treatment of different diseases and also in the production of different hair care products, including oil, lotion, shampoo, etc.
• There are a few species of non-flowering plants, which are widely used as ornaments for decoration purposes. For example- fern.
• Oil extracted from the barks, wood and other parts of the plants are used in the cosmetics industries in the production of perfumes, room fresheners and other fragrance spray.
• Other than the food and medical applications, a few of these non-flowering plants are widely grown in gardens, parks and in other places as these plants possess beautiful ornamental leaves.

Other than these significances, gymnosperms have further economical importance too. These species are widely used in the production of:

• Certain medicines for the treatment of malignant ulcers.
• Mounting medium during microscopic examination in laboratories.
• Gum extracted from cycas trees are used as the antidote for snake bites.
• The wood of these plants are widely used in paper manufacturing industries.
• The leaves of cycads are used for preparing handbaskets, brooms, hats, door and floor mats and other eco-friendly products.
• Similar to teak and rose wood, the wood obtained from the barks, stem and the branches of the pines trees are also used for the production of beams, doors, flooring, poles, railway wagon, etc.

This article concludes an introduction to gymnosperms and their economic importance. To know more about gymnosperms, their types, features, other related topics and important questions on gymnosperms, keep visiting our website at BYJU’S Biology .

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Economic Importance of Gymnosperms

The economic importance of Gymnosperms extends to their role in soil stabilization, erosion prevention, carbon sequestration, and as a habitat for wildlife. Gymnosperms hold economic significance as they provide timber, paper, and medicinal extracts, sustaining various industries and providing valuable resources. In this article, we will discover gymnosperms' different uses and economic importance .

Table of Content

What are Gymnosperms?

• Features of gymnosperms

Importance of Gymnosperms

Conclusion - economic importance of gymnosperms, faqs on economic importance of gymnosperms.

" Gymnosperm " means "naked seeds" as it is derived from the Greek words "gymno" (naked) and "sperma" (seed). The gymnosperms and angiosperms difference lies in the fact that gymnosperm plants do not produce fruits in addition to their seeds. These plants grow into a cone-shaped structure at the tips of stalks, on the surface of scales or leaves, or both.

The kingdom Plantae and subkingdom "Embryophyta" are home to gymnosperms. Based on fossil evidence, they originated 390 million years ago, during the Paleozoic era. Gymnosperms lack ovarian walls enclosing their ovules. It stays exposed both before and after fertilization, as well as before seed development. Both branched and unbranched gymnosperm stems are possible.

Also Read : Difference between Angiosperms and Gymnosperms

Gymnosperms are important to the economy because of their uses in horticulture, paper, lumber, medicine, and the environment.

• Gymnosperms are important to the economy because they are a great source of food and are frequently used to make staple foods that can be eaten.
• Ginkgo, pinus , and cycas are examples of this kind of plant.
• Additionally important providers of starch, gymnosperms are the raw material for sago.
• Some parts of America and the surrounding regions dip and eat the leaves of these species as green leafy vegetables.
• Many types of non-flowering plants are used to make wine and other food items.
• 'Seed starch' extracted from seeds like Cycas rumphii, Dioon edule , etc., is processed into flour and cooked before consumption.
• Cycas' tender leaves are commonly prepared and consumed as a vegetable .

Medicinal value

• Gymnosperms are widely used in the pharmaceutical industry to make a wide range of drugs, including those that treat allergies and infectious diseases like colds, coughs, asthma, and respiratory congestion .
• Taxol is a medicine made from Taxus, a coniferous tree.
• Cycas plants come in a variety of varieties and are used to make shampoo, oil, lotion, and other hair care products as well as to treat a range of illnesses.
• Ephedrine, an alkaloid derived from Ephedra.
• The juice derived from the young leaves of Cycas revoluta is employed in the treatment of blood vomiting and flatulence .

Industrial Use

Gymnosperm plants are utilized in a variety of industrial applications, such as these:

• Cycas gum is applied topically, as a remedy for snake bite, and for treating dangerous lesions.
• Tannins from the bark of various trees, including Sequoia, Pinus, and Araucaria , are utilized in the leather industry.
• A balm used in organic preparations, turpentine is extracted from Abies balsamea .
• Resin from fossilized Pinus succinifera is found.
• Aside from flooring for wagons, pinus wood is used for doors, pillars, and beams.
• Podocarpus wood is used to make plywood.
• Pinus, Picea, Abies, Gnetum, and other species' wood pulp is used to make publications like newsletters, stationery, and prints.
• Fibers extracted from the leaves of Cycas and Macrozamia are employed in stuffing pillows and crafting mattresses.

Source of oil and wood

• Gymnosperms like C. revoluta, Macrozamia riedlei, Pinus cembra, and Cephalotaxus drupaceous are among the plants whose seeds are used to make edible oils.
• Tiny objects and oil-sopped lenses are cleaned with red cedar oil, which is extracted from the heart skin of Juniperus virginiana .
• Oils extracted from Cedrus deodara, Cryptomeria japonica, and Cupressus sempervirens are employed in the preparation of perfumes.
• Red cedar wood oil , obtained from the heartwood of Juniperus virginiana, is employed for cleaning microscopic preparations and as a lubricant for oil immersion lenses.

Aesthetic value

In addition to their decorative value, gymnosperms are used in the following ways in business:

• Garden plants and ornamental plants are commonly grown from several species of Cycas .
• Chinese and Japanese temples revere the ginkgo, or "virgin," tree, and grow it as a beautiful plant.
• Several gymnosperms, such as Araucaria, Thuja , and others, are cultivated for ornamental purposes.

The exudates from plants are produced by specific channels. These originate primarily from tapping conifers. They are widely used in paints, lacquers, varnishes, medicines, and paper manufacturing; they are soluble in organic solvents but insoluble in water.

Rosin, or colophony, is the byproduct obtained from distilling turpentine or pine oleoresin . The primary sources of turpentine in India are Pinus roxburghii, P. wallichianus, P. insularis, and P. merkusii . Turpentine oil and rosin are distilled to make them. Parchment, enamel, plasters, ointments, and paper sizing are all made with rosin. Excellent rosin is needed for the production of grease and oil, sealing wax, oilcloth, plastics, adhesives, insulators, disinfectants, insecticides, furniture, and a host of other industrial stuff.

Features of Gymnosperms

Gymnosperms are distinguished by the following key traits:

• They do not make flowers.
• No seeds develop inside of a fruit. They have no clothes on.
• They can be found in colder climates with snowfall.
• They grow leaves that resemble needles.
• They grow into bushes or trees and are woody or perennial.
• They are not classified according to stigma, style, or ovary.
• They are directly pollinated by the wind because they lack stigma.
• Only one of the two gametes that the male gametophytes produce is viable.
• They develop reproductive organs into cones.
• The endosperm found in seeds stores nutrients necessary for the plant's continued growth and development.
• Due to the vascular tissues in these plants, water and nutrients are more easily transported.
• The phloem lacks sieve tubes, companion cells, and vessels, while the xylem lacks all three.
• Gymnosperms are plants that produce food. These non-flowering plants are used extensively for their edible seeds, which are used to make a variety of food products. Ginkgo, pinus, cycas, and other plant species are among them
• In addition to being used to make sago, a few gymnosperm species are useful sources of starch. Lowland or indigenous peoples rely heavily on it as a staple food.
• The leaves of these plant species are soaked and consumed as green leafy vegetables in some lowland areas of America and other countries.
• A wide variety of non-flowering plant species are employed in the manufacturing of wine and other food products.
• Cycas plant species are utilized in the pharmacological and cosmetic industries to make a variety of hair care products, such as shampoo, lotion, and oil.
• A few species of non-flowering plants are frequently used as decorations for aesthetic reasons. Take that fern as an example.
• Some of these non-flowering plants are commonly grown in gardens, parks, and other locations in addition to being used for food and medicinal purposes because of their lovely ornamental leaves.

Also Read: Diagram of Flower - Parts & Functions

Gymnosperms are important to the economy because of their uses in horticulture, paper, lumber, medicine, and the environment. They are also beneficial for recreation and the environment. They supply wood, paper, resins, and board, edible seeds—some of which can even be used to make medications. Globally, the Coniferales represent a significant timber resource, producing wood that is employed globally in a multitude of ways. The most common commercial use of Pirius brxburghii (Chir) is in India. Making sound boards for musical instruments is one use for spruce ( Picea ).

Also Read: Fertilization in Plants - Process, Diagram and its Types NCERT Solutions for Class 11 Biology Chapter 3 – Plant Kingdom What is Plant Kingdom? Classification of Plants Morphology Of Flowering Plants

Give a Few Examples of Gymnosperms.

Cycas, Pinus, Thuja, Cedrus, Abies, and Larix showcase gymnosperm diversity crucial for Earth's ecosystems.

What is the Most Important Gymnosperm?

Conifers, the most species-rich gymnosperms, also exhibit remarkable ecological diversity. They play a crucial role in temperate and boreal forest ecosystems.

What is the Economic Importance of Algae and Gymnosperm?

Algae contribute to oxygen production, food chains, and biofuels, while gymnosperms offer timber, paper, and pharmaceutical resources, both playing vital economic roles.

What is the Most Economically Important Group of Gymnosperms?

Gymnosperms, such as pine, fir, spruce, and cedar, are economically vital for lumber, paper, and resin industries. They also have diverse applications in soap-making, varnish, nail polish, food etc.

Why were Gymnosperms Important?

Gymnosperms serve as a valuable food source, with edible seeds utilized in various food products. Additionally, certain gymnosperm species are rich in starch, making them suitable for sago production.

What are the Ecological and Economic Importance of Gymnosperms?

Gymnosperms contribute to biodiversity, soil stabilization, and carbon sequestration in ecosystems worldwide. They provide valuable resources such as timber, medicine, and ornamental plants, supporting industries and livelihoods.

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Economic importance of gymnosperm

Gymnosperms are the group of plants whose seeds have no covering or they are not covered by fruit or ovary. Gymnosperms are found in the temperate zones as well as higher tropics. Gymnosperm trees find a variety of use especially for timber used in construction, obtaining resins as well as in paper manufacturing. Many Gymnosperm trees also have medicinal properties and yield essential oils.

Every plant undergoes cycle, that includes development from small to well developed larger and broader plant. Gymnosperm plants also undergo life cycle to become a mature plant and this life cycle shows dominant saprophytes and reduced gametophyte. In such plant; sexes are separate, hence can be monoceious and dioecious. Therefore, these are the plants with diverse characters where pollination occurs by landing of pollen directly on the ovules. Some of the examples of gymnosperm plants are: conifers (these are the most common gymnosperm alive), cycads (found in tropical and sub- tropical regions and produce cones and sporangia), gnetals (these are group of monophyletic family), ginkgo (dioceous plant with unprotected ovule).

Some of the Important Uses of Gymnosperms are:

1. These plants are very useful in making furniture’s and for other construction purposes. 2. They are the sources of food to animals and human. 3. The strong roots of gymnosperm prevent from soil erosion. 4. Gymnosperm plants are also scientifically important because they provide lots of evidence about the past. 5. Beside these points, gymnosperm is also used as lumber. 6. They are also used to make perfume, oil, nail polish and many more.

The stems of genus Cycas is a source of Sago which is consumed as food. Also Cycas plants have ornamental uses. The leaves of many Cycas plants are used in making brooms, hats, baskets.

Ephedra gerardiana is used to obtain Ephedrin, an alkaloid used to treat Asthma, Bronchitis and various other respiratory disorders. The bark of Gnetum gnemon,   G. latifolium  and  G. ula is used to obtain Fiber for making fishing nets and ropes. Ginkgo biloba  is an ornamental plant which is widely worshipped in China and Japan.

In Pinophyta, taxus woods are used to obtain Timber for making Pencils. Taxus brevifolia is is a source of ‘Taxol’, an important medicine used for curing cancer. Coniferales are an excellent source of high grade soft wood which are resistant towards insects and fungus. These woods also have good durability and are of light weight. Agathis australis  is the largest timber producing tree of the world. Some species also produce scented woods such as the heart wood of Cedrus deodara which are used in making doors, railway sleepers and boats. The wood obtained from Araucaria araucana is used for making airplanes and it’s propellers.

Conifers such as Pinus australis, P. caribaea are excellent producers of resins. Resins are used in various industries such as Varnishes, Plasters and Enamel Paint because they are resistant to decay. Agathis australis is used to obtain Copal which is a tougher non-elastic resin with no oil. Yellow And Orange colored resins called Sandarac are obtained from Callitris calcarata. It is mixed with metal varnishes and also used in glass and porcelain industries. Pinus sucinifera tiled is a source of fossilized resin called Amber. Amber is used to make pipes and cigar holders as well as in jewellery.   Pine trees such as Pinus palustris, P. pinea, P. roxburghii, are used to produce oleorosins and gum rosin which are brittle aromatic solids used to manufacture soaps, varnishes and printing ink. Abies balsamea is is a source of Canada Balsam which has a refractive index same as that of glass. It is used for cementing lenses. Trees of Araucaria, Agathis, Dacrydium, Phyllocladus, Pinus, Picea  and Sequoea are used to obtain Tannins. Tannins are a key component in leather industry.

Various species also produce aromatic oils and essential oils. Picea glauca  and  Tsuga canadensis  are a source of oil of hemlock which is used as room spray and deodorant. Juniperus  species , Pinus  species are also used to obtain wood pulp to make paper.

Therefore, gymnosperm plants are very important and there are lot more in the topic that need to be learnt. There are many more importance of gymnosperm and assignments on this topic generally covers either its life cycle or its importance. Apart from this, finding out about importance of gymnosperm needs lots of research and understanding. To make your understanding and work easier feel free to take help from AssignmentHelpNet. Our Biology experts and highly qualified Botany tutors are available for the students all round the corner; they can switch to the site and get answers to all their queries. In fact, the assignments on gymnosperm and its importance are also well handled by the teachers here and they will provide students well framed and presentable assignments as per the requirement.

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Gymnosperms: Characteristics, Types and Economic Importance

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In this article we will discuss about:- 1. Characteristics of Gymnosperms 2. Types of Living Gymnosperms 3. Economic Importance.  

Characteristics of Gymnosperms:

Gymnosperms are, those seed plants in which the seeds remain exposed over the surface of the megasporophylls because the latter are not folded to form pistils.

1. Gymnosperms are a small group of seed plants which are represented by only 900 living species.

2. Gymnosperms are more ancient than the angiosperms. They formed dominant vegetation on earth some 200 million years back in mesozoic era. Today they are dominant only in cold areas, where instead of rain; snow is the source of water.

At other places they have been replaced by angiosperms. In warmer areas only a handful of gymnosperms can be observed, e.g., Cycas (like C. circinalis in South India), Araucaria (native of South America, New Zealand and East Australia, like A. heterophylla.

3. All gymnosperms are perennial and woody, forming either bushes or trees. Some of these are very large and live for thousands of years, e.g., Sequoia sempervirens (tallest gymnosperm of 111.6 m) Zamia pygmia is smallest (26 cm).

4. Flowers are absent. Two types of sporophylls, microsporophyll’s and megasporo­phylls are usually aggregated to form distinct cones or strobili, pollen cones (male cones) and seed cones (female cones) respectively.

5. Seeds do not occur inside a fruit. They are naked.

6. A distinction of ovary, style and stigma is absent.

7. Ovules are orthotropous and sessile. Each ovule is surrounded by a 3-layered integu­ment.

8. Female gametophyte contains archegonia.

9. Pollination is direct as a stigma is absent and the pollen grains directly reach the micropylar ends of ovules. Pollination is usually accomplished by wind (anemophily).

10. Male gametophyte produces only two male gametes or sperms. Generally one of them is functional.

11. An external water is not required for transport of male gametes. Instead, a pollen tube is formed by the male gametophyte for effecting fertilization (siphonogamy).

12. Seeds contain a food laden tissue or endosperm for future growth of embryo into seedling. The tissue represents the female gametophyte.

13. Like pteridophytes, xylem does not possess vessels except in some geophytes. Phloem is without companion cells and sieve tubes. Sieve cells are not arranged end to end in rows.

14. Vascular tissues are arranged into vascular bundles just like angiosperms. Vascular bundles of stem are open so that secondary growth is quite common.

Types of Living Gymnosperms:

Living gymnosperms are divided into four groups— Cycadopsida, Ginkgopsida, Coniferopsida and Gnetopsida. Ginkgopsida is represented by maiden hair tree (Ginkgo biloba).

Gnetopsida contains Gnetum, Ephedra and Welwitschia. These are nearer to flow­ering plants in having flower like arrangement of sporophylls and possessing primitive vessels in xylem. Plants of cycadopsida and coniferopsida are commonly called cycads and conifers respectively.

It is smaller group of gymnosperms which have palm-like habit and fern-like foliage. Leaf bases are often persistent. In stem the vascular tissues constitute only a narrow patch though secondary growth occurs. Plants are dioecious, that is, microsporophyll’s and megasporophylls develop on separate plants. The sporophylls are aggregated to produce strobili or cones (exception megasporophylls of Cycas).

Megasporophylls are often leaf-like and possess ramenta. Sperms are motile. The plants are mostly xerophytic and occur in warm weather. Their population is, however, decreasing due to extension of agriculture and severe competition from xerophytic angiosperms. Cycads are grown for their ornamental appeal, e.g., Cycas circinalis, C. revoluta.

Cycas (Fig. 3.18):

Cycas is also called living fossil because it possesses a number of characters of extinct pteridosperms and cycads. The gymnosperm is an evergreen small palm-like or tree-fern like sporophyte that occurs in some tropical and subtropical areas.

It reaches a height of 0.4 m to 20.0 m. Cycas has an un-branched columnar stem (rarely branched) which is covered by spiral bands of persistent rhomboidal leaf bases. The top bears a crown of leaves.

Leaves are of two types, large green foliage and small brownish scale leaves. Scale leaves develop in spiral rows alternating with foliage leaves. They are covered with ramental hair. Foliage leaves are large (1-3 m), petiolate and unipinnate. Base is broad. Petiole bears two rows of spines. Petiole continues into rachis. Rachis has two lateral grooves from which arise 50- 200 pairs of sessile, linear-lanceolate pinnae or leaflets.

Leaflet apex is spiny while the margin can be straight or revolute (e.g., C. revoluta, C. beddornei). Young leaves show circinate ptyxis. Roots are of two types, normal and coralloid.

Coralloid roots are irregular, negatively geotropic, dichotomously branched coral like roots which do not possess root hairs and root caps. Coralloid roots have a symbiotic association with blue-green algae like Nostoc and Anabaena species. Sago grains occur in the stem cortex.

Vegetative reproduction occurs by fleshy bulbils which arise adventitiously in the crev­ices amongst persistent leaf bases. Sexually Cycas is dioecious with distinct male and female plants. The plants bear terminal cones. Male cone is oval, thick, 20-80 cm long stalked structure which replaces the growing point of the plant. Further growth of male plant is carried out by a lateral bud, so that stem axis of male plant is sympodial.

Male cone has a number of densely crowded spirally arranged microsporophyll’s. Each microsporophyll has a flat fertile proximal region and a distal bent sterile region or apophysis. The fertile region bears a number of microsporangia or pollen sacs arranged in sori. Microspores or pollen grains are boat-shaped.

Female cone is loose. It consists of a rosette of brown megasporophylls. Each me­gasporophyll bears 2-12 reddish ovules in the middle fertile part. The terminal sterile part may show remains of foliar structure. Ovules of Cycas are the largest, 6-7 cm in diameter. Similarly, egg or oosphere is the largest in plant kingdom.

Pollination is anemophilous. Before pollination, pollen grain develops three cells prothallial cell, generative cell and tube cell. Pollination brings pollen grains inside the ovules. The tube cell grows and forms a pollen tube. Pollen tube is haustorial in function in Cycas. Generative cell divides into sterile stalk cell and large fertile body cell. Body cell produces two sperm mother cells.

The sperms of Cycas (upto 300 pm) are the largest in the biological world. They are top-shaped with a number of flagella present in 5-6 grooves on the pointed end. Seed is oval to rounded orange-red structure which generally has a fleshy outer sarcotesta for attracting birds.

ii. Conifers:

They comprise more than 500 living species of cons bearing gymnosperms which have withstood competition from angiosperms. The plants are evergreen with dense and massive vascular tissues and non-motile gametes. Conifers are usually monoecious. Cones or strobili are compact and woody. Both the types of cones are borne on the same plant. Unlike cycads, they are not produced on the tips of main branches.

Conifers have monopodial growth where the main axis of trunk rises straight from base and reaches up to the tip. The branches do not compete with the main axis. Stem branches are of two types, long and dwarf. Growth of the long branches is indefinite. The lower long branches are longer than the upper ones. This gives a conical or ex-current appearance to the plant just like a ‘Christmas Tree’.

Leaves are mostly borne on the dwarf branches. The dwarf branches have a limited or definite growth. Leaves have thick cuticle and sunken stomata. They are needle like (e.g. Pinus), small flat and leathery (e.g., Araucaria) or scale like (e.g. Thuja). All these leaf characters help conifers in conserving water and reduce transpiration in dry conditions associated with cold habitat.

The roots are often associated with fungal symbionts or mycorrhizae so as to overcome difficulty in absorbing water and obtaining inorganic nutrients from organic debris.

The plants usually possess an aromatic antiseptic sticky semifluid substance called resin. It is secreted by special channels or ducts present in wood, bark, leaves, roots, etc. Resin seals the places of injury and protects the plants from attack of microbes as well as insects.

Araucaria (a tall and majestic conifer of South America, New Zealand and East Australia) grows in warm weather in plains as well as foot hills.

Other conifers form vast and dominant woodlands in mostly north temperate regions of Europe, Asia, North America, etc. They are abundant on the upper timber-line zone of mountains including the Himalayas, e.g., Pinus (Pine), Cedrus (Cedar), Picea (Spruce), Abies (Fir), Juniperus (Juniper), Thuja, Larix, Cupressus.

Conifers are dominant constituents of north temperate flora due to the following reasons:

1. In the temperate areas, conifers have an advantage over angiospermic trees. While the angiospermic trees shed their leaves during autumn-winter period, the conifers remain evergreen. They continue to manufacture their food during this period when other plants are in a state of hibernation because of the absence of leaves.

2. Conifers have a number of xerophytic characteristics which help in conserving water. They are, thus, able to tide over the winter period when the soil becomes frozen and water availability is very little. Mycorrhizae allow them to get water and minerals.

3. Enzymes of conifers are functional even at —35°C at which temperature they become inactivated in other plants.

Pinus (Fig. 3.18):

Pinus or Pine is a coniferous gymnosperm. It is a large tree having pyramidal or ex-current shape like a Christmas tree. The plant body is a sporophyte having stem, leaves and roots.

The main stem is straight. It may reach a height of 10-50 metres. The main stem shows monopodial branching. Stem branches are of two types, long and dwarf. The dwarf branches possess 1-5 needle-like foliage leaves which are surrounded at the base by a sheath of scale leaves.

Pinus has a horizontally spreading tap root system with peg-like down­wardly directed roots present at intervals. Finer roots are of two types— normal (with root hairs and root cap) and mycorrhizal. The mycorrhizal roots occur near the soil surface. They are devoid of root hairs and root cap.

The sporophytic plant body does not multiply vegetatively. It produces micro- and mega­sporophylls in two types of cones, male and female. Male or pollen cones occur in clusters sub-terminally on lower long branches. Each male cone has a short stalk, a central axis and a number of spirally arranged microsporophyll’s.

A microsporophyll bears two oblong, parallel microsporangia on its lower surface. Pollen grains are dispersed by air currents. They form yellow clouds in the pine forests. A pollen grain has two air sacs or wings for making it light.

The female or seed cones develop in groups of 2-6 on upper long branches of the tree. Each female cone has a long stalk and a central axis on which are borne a number of spirally arranged paired scales. The lower of the pair is called bract scale while the upper scale is ovuliferous scale or megasporophyll. The ovuliferous scale bears two ovules towards the basal region on the upper side.

The female cones open in the year of their formation for pollination. Pollination is anemophillous (by air) and direct. After fertilization the ovule matures into a seed.

Part of the upper surface of the ovuliferous scale is peeled off along with the seed to form its wing. A female cone takes about 26 months for reaching maturity. It then opens to release winged seeds which are dispersed by air. After falling on a suitable soil, each seed gives rise to a new plant.

iii. Ginkgoales:

They are primitive gymnosperms which possess deciduous leaves with furcate venation, two types of branches, unisexual plant, catkin like male inflorescence with each microsporangiosphore having 2-12 microsporangia, multi ciliate male gametes and clusters of megasporangiate structures each with a long stalk and two ovules. Ginkgoales are rep­resented by a single species, Ginkgo biloba.

Ginkgo biloba:

Ginkgo biloba (Fig. 3.19) has not changed for the last several millions of years since its appearance in triassic period. It is also called living fossil. The plant has survived due to interest shown by horticulturists. It has natural im­munity to several plant diseases. The plant is a tall tree of upto 30m height. Leaves are fan-shaped.

They are deeply bilobed on long shoots. The leaves are entire or sinuate on dwarf shoots. Leaves pos­sess furcate venation. Ginkgo is dioecious like cycads. Dwarf shoots of female plants bear distinct megasporangiate structures.

Each has a stalk that ends into two ovules. Ovule has a 3-layered integu­ment, micro Pyle and a pollen chamber. Endosperm of roasted seed is edible. However, horticulturists prefer to grow only male plants as the female plants give unpleasant smell.

Economic Importance of Gymnosperms:

Some of the Major Economic Importance’s of Gymnosperms are given below:

1. Edible Seeds:

Seeds of Pinus gerardiana are edible. They are eaten after roasting.

Gymnosperms possess softwood. The same is used in preparation of light furniture, plywood, packing cases, match sticks, railway sleepers, etc.

A number of gymnosperm woods are used in the manufacture of paper. They include Picea, Pinus, Larix and Abies.

4. Fibre Boards:

Needles of Pinus and other conifers are used in making fibre boards that are used in making packing cases.

5. Linoleum:

Saw dust is employed in making linoleum and plastics.

Resin is a semifluid secreted by special tubes which contains terpenes, resin acids and esters. It solidifies on exposure to air. Therefore, it plugs the places of injury. It helps in sealing female cones after pollination, scale leaves around leaf bases and apical buds. Resin retains water. It is antiseptic and toxic to pests.

Therefore, it prevents microbial and insect attack. Resin is commercially extracted and distilled to obtain turpentine and rosin. Rosin is used in water proofing, sealing joints and preparation of writing paper. Turpentine is used as solvent in paints, polishes and wax. It is employed medicinally in removing pains, curing bronchitis and expelling worms.

7. Ephedrine:

Drug ephedrine is obtained from Ephedra, a gymnosperm. The drug is used in curing respiratory ailments, including asthma.

Related Articles:

• 18 Important Characters of Gymnosperms – Explained!
• Pteridophytes and Gymnosperms: Comparison | Plants

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