Gymnosperms are an economically important group of plants, thriving as trees in temperate regions and high altitudes of tropics. These are important in landscaping. Gymnosperms are valuable for their timber. In industry these are used for the manufacture of paper, furniture, varnishes, medicines, perfumes and essential oils.
Beauty of a hill station lies in its conifers; pine, cedar, fir, spruce and hemlock. Their stately appearance, symmetrical growth and evergreen nature are a treat to the eye. Cycas, because of its unique beauty of thick cylindrical stem and conspicuous crown of pinnate leaves, is a pride possession in gardens and parks.
Young Pinus, Abies, Picea and Araucaria are used as Christmas trees. The white cedar is an attractive landscape tree, cultivated for hedges and as windbreak. It is also grown as Christmas tree in Indian plains.
In the art of ‘Bonsai’, Pinus parviflora, P. thunbergii, P. densiflora, P. nigra and P. mugo are preferred. Ginkgo, an ornamental, is worshipped in Buddhist temples of Japan and China. Ephedra girardiana is an ornamental and E. campylopoda, a pendulous plant is grown in hanging baskets and grows in crevices of the wailing-wall in Jerusalem.
Woody gymnosperms of the past are a source of modern coal.
Newspaper industry is wholly dependent on the softwood of present-day conifers. Good quality writing and printing paper is possible from the wood of Abies, Picea and Tsuga, whereas kraft paper is obtained from Pinus. The pulp of Picea is the best, because of its light colour, low resin content and long fibre and hence, spruce is the king, the other products such as rayon are derived from the pulp of Picea.
Conifer wood is soft, straight-grained, light-coloured and light-weight. It is preferred for cabinet- and furniture-making and interior decorations. Abies alba is an important timber tree of Europe, for its wood is used in general carpentry.
Wood of A. anabilis (Alaska), A. grandis (Canada), A. concolor and A. procera (N. America) is used for interior furnishing and box-making. A. delavayi is an important timber tree of China. In India, the wood of A. pindrov and A. spectalis, which is pale yellow, lustrous and straight-grained, is used for making matchsticks and packing boxes, camp furniture, paper and pulp.
Wood from Cedrus deodara (India), C. atlantica (Algeria and Morocco), C. Libani (Lebanon) is in great demand due to its durability and sweet scent. Cedrus of Lebanon (C. libani) was called the “Tree of God”, because its wood was used for roof beams in the temples of Egypt. Its wood was also used for making mummy cases and coffins.
C. deodara, the devdar, is one of the most favoured timber trees in north India. Its seasoned wood is resistant to insect attack due to the presence of oil. The wood is used for making doors, furniture, beam ceilings, flooring and wood carving.
Cryptopmeria japonica is the most utilized timber tree in Japan for its coarse-grained wood, which is strong, durable and fragrant. The bark of the tree is carefully stripped and used for roofing of houses. The wood of Cupressus lusitanica and C. macrocarpa (E. Africa and Australia) is yellow to brownish, odorous, resinous, durable and is used in furniture making, building construction and for poll fencing. Wood of C. torulosa (North Himalayas) is durable in contact with ground and is valued for furniture, railway sleepers and aircraft manufacture. It is preferred over devdar because it does not exude any oil and can be painted and polished.
Durable, heavy and fine-textured wood of cedar scent is for pencil making, ship building and carpentery. It is obtained from Juniperus bermudiana (Central America) and J. procera (East Africa). In Bermuda, cabinets made of J. bermudiana are highly priced.
Fibres extracted from the leaves of Pinus palustirs and P. sylvestris (scots pine) are utilized for stuffing mattreses, cushions and pillows. Wood from P. cembra (Europe and N. Russia) is light, durable and straight-grained, which makes it suitable for cabinet making, indoor furnishing and toy making.
Non-aromatic fine-textured wood of Podocarpus amarus and P. elatus (New Zealand) is valued for carving. Wood of Thuja plicata is most durable due to the presence of certain antibiotics. Weather resistant properties of its wood makes it valuable for glasshouse construction.
Taxus baccatta, the common yew, has the heaviest wood amongst the softwoods. The yew wood is also used in making candlesticks and curios. Because of its extraordinary elasticity Yew wood is used for making bows for archery. Taxodium distichum thrives in swampy areas of America, yields dark-coloured and durable wood.
Resins:
Conifers are well-known for their resins, superior grades of which are employed in varnish, enamel, plaster, medicine and ointment industries. Inferior grades go in soaps, painting, inks, oil cloths, insulation, greases, insecticides, adhesives, plastics and making of shoe polish. Metal resins, on inclusion of lead and magnesium, are valued as paint drier.
Pine oleo-resin was used to smear mummies by ancient Egyptians. Oleo-resin is a mixture of resin and essential oils.
As for turpentine, USA is the largest producer, followed by France, India and other East Asian countries. Pine species yielding turpentine are P. palustris and P. caribea (USA), P. helpensis, P. nigra, P. pincea and P. sylvestris (Europe) and P. roxburghii, P. wallichiania (India), P. khasiya (Philippines) and P. merkusii (eastern India).
Many species of Pinus are tapped for turpentine oil obtained by distillation of oleo-resin, steaming of wood chips and condensates recovered during sulphate process of cooking wood pulp. The turpentine oil obtained by last two processes is used as an industrial solvent and for reclaiming rubber. Several esters of picric acid prepared from turpentine oil are used as lubricant for jet aircraft and plasticizers.
Tapping of pine trees is done in India. Its flow is increased on employing sulphuric acid or inoculation of fungus Fusarium because these do not allow the wounds to heal quickly.
Essential oils from conifers that yield resin are not exploited for commercial purposes because of an alternative availability of synthetic ones.
Picea abies that yields burgundy pitch, a purified resin from its branches and leaves, is a distilled “swiss turpentine”, fermented liquor. Spruce-beer is obtained from an extract of its young shoots and leaves, mixed with molasses.
Copal is hard resin which is obtained both from fossil as well as living trees. Of the copals the most valued is kauri resin obtained from kauri pine {Agathis australis) which occurs in fossilized form. New Zealand is the largest producer of kauri copal. The other type is East India Copal or Manilla copal from Agathis alba that grows in Malaysia, Sumatra, Philippines, Celebes, Moluccas and New Guinea.
Fossilized resin is superior to fresh resin. Copal resin is used for interior work, linoleum, plastic, oil cloth, water proofing compounds and painting. The resin of Araucaria angustifolia is fragrant and is mixed with wax to make candles. Fresh resin from A. araucaria is a remedy for bruises and wounds.
Amber is fossilized resin secreted by extinct pine, Pinus succinifera that occurred near the eastern shore of Baltic, Sicily, Madagascar and Myanmar. It is obtained through mining and is used in x-ray therapy, beads and other ornamentals, mouth pieces of cigars and cigarettes and mouth pieces of smoking pipes.
Sandarac is hard resin obtained from the trunk of Tetraclinis articulata (African Sandarac) and Callitris spp. (Australian sandarac). The best grade of sandarac is obtained from the ground near the tree. It is also used for the preservation of fine paintings, cementing glass and porcelain.
Canada balsam is the resin obtained from Abies balsamea. Since it has high refractive index near that of glass, so it is most preferred as mounting medium for microscopic slides and as a cement for lenses by opticians.
Oil:
Pine oil, recovered during steam and solvent process extraction of wood from old stems is used as frothing, in separation of metals by floatation.
Spruce oil from Picea abies is used in room sprays. The oil, Hemlock-spruce from Tsuga canadensis is used in the USA. Siberian fir (Abies sibrica) yields needle oil which is the best among pine, fir and spruce needle oils.
In India, oil extracted from Cedrus deodar is used in perfuming and scenting of soaps. Oil obtained from the distillation of fleshy cones of Juniperus communis is used to flavour liquors, gin and alcoholic beverages. Italy is the largest producer of it, followed by Hungary, Czech, Slovak and Yugoslavia.
Fatty oils, seeds of gymnosperms contain fatty oils. However, seeds have not been exploited commercially because they are more useful if consumed as nuts.
Food:
Chilgoza, seeds of Pinus girardiana which occur in the Himalayas are eaten in India, Afghanistan and Pakistan. In Europe, P. pinea is the edible pine. Ginkgo biloba is cultivated in China and Japan for its edible seeds. Gnetum ula is cultivated in Malaysia for its edible seeds. In some parts of the world ‘sago’ is the starch from Cycas circinals, C. rumphii and C. revoluta. The plants are cut and their innermost cylindrical axis is dried and made into flour and finally made into spherical granules called sago.
Drugs:
An alkaloid ephedrine, for its action in dilating of bronchial tubes, is obtained from green twigs of Ephedra sinica, E. equisetina and E. gerardiana. Ephedrine also contracts mucous membranes so is used as nasal drops.
Extract from leaves of Ginkgo biloba is useful in the treatment of cerebral insufficiency and vertigo.
Taxine from the leaves of Taxus bacccata is used in asthma, bronchitis, high cough, epilepsy and indigestion.
Taxol from Taxus brevifolia in effective against the cancer of ovaries, breast cancer, non- small-cell-cancer, melanoma and colon cancer. However, many trees need to be felled for a small quantity of this drug.
Gum exuded from gum canals of megasporophylls, stem and leaves of Cycas is used as antibiotics for snake and insect bites.
Oil from Abies alba (Europe) is used in medicines for the treatment of cold and rheumatism.
Juniperus oxycedrus which grows in Spain, in barren Mediterranean, yields ‘oil of cade’ for the cure of chronic eczema.
Micropropagation of Gymnosperms:
Macropropagation of conifers by rooted cuttings is an established practice in Europe and USA, but micropropagation of these plants through Cell, Tissue, Organ, and Protoplast cultures have not given tangible results. However, a sliver-lining has been shown by the embryo culture, which has turned out to be most successful technique.
Adventitious bud formation was reported for the first time on embryo culture of Biota orientalis. This was extended to Ephedra foliate Pinus palustris Pseudotsuga menziesii Picea glauca Pinus wallichiana (Fig. 19.1. A, B, Konar & Singh 1980) and Cedrus deodara. An important factor in micropropagation is the selection of explant. Cotyledons and hypocotyls have turned out to be most responsive.
Germinated and young seedlings (2-to 4-week old) show highest capacity for organogenesis. Cotyledons from germinated seedlings usually produce more shoot-buds than ungerminated seeds.
As for cotyledons, adventitious bud formation has been reported for several conifers, like Pinus taeda, Pseudotsuga menziesii, Pinus strobus, Pinus marina and Picea glauca. P. radiata Picea abies and Abies fraseri. Cells in epidermal and sub-epidermal layers of cotyledons are the sites for active division. They result in meristematic centers that form shoot apices.
There are reports of “embryonal suspensor masses” in cultures starting from embryos of Picea abies. Picea glauca, Psuedotsuga menziesii, Pinus taeda and Larix eurolepis.