question_answer 5)

Write a note on economic importance of algae and gymnosperms.

Answer:

Economic Importance of Algae (i) Red algae provides food, fodder and commercial products. Porphyra tenera (laver) is rich in protein, carbohydrates and vitamin-A, B, E and C. (ii) Corallina has vermifuge properties. (iii) Agar-agar a gelatin substance used as soldifying agent in culture media is obtained from Gelidium and Gracilaria algae. Funori is a glue used as adhesive and in sizing textiles, papers, etc. Chondrus is most widely used in sea weed in Europe. (iv) Mucilage extracted from Chondrus is used in sampoos, shoe polish and creams. (v) Carrageenin is a sulphated polysaccharide obtained from cell wall of Chondrus crispus and Gigartina and is used in confectionary, bakery, jelly, creams, etc.   Economic Importance of Gymnosperms (i) Gymnosperms hold soil particles and thus check soil erosion. (ii) Many gymnosperms are grown in gardens as ornamental plants, i.e., Cycas, Thiya, Araucaria, Taxus, Agathis, Maiden hair tree, etc. (iii) Sago is a kind of starch obtained from cortex and pith of stem and seeds of Cycas. Roasted seeds of Pinus gerardiana (chilgoza) are used as dry fruit. (iv) Paper pulp is obtained from wood of Picea (spruce), Gnetum, Pinus (pine) and Larix (larck). (v) The wood of Juniperus virginiana (red cedar) is used to make pencils, holders and cigar boxes. Wood of Taxus is heaviest amongest soft woods and is used for making bows for archery. (vi) Dry leaves of Cycas are used to make baskets and brooms. Needles of Pinus in making fibre board. Electric and telephone pones are made of stem of conifers. (vii) Essential oils are obtained from Juniperus, Tsugo, Picea, Abies, Cedrus, etc. Resins are obtained from many species of Pinus.