What are secondary metabolites ? Briefly explain their uses.
A. 1) The materials which do not require for normal growth and development are called secondary metabolites. These are the by-products of plants, eg: Alkaloids, Tannins, Resins, Gums and Latex etc, Though plants produce these chemicals for their own use man found the usage of these chemicals for own benefits. They are generally coloured and fragrant.
2) Alkaloids: These are nitrogenous by-products and poisonous. These are stored in different parts of the plants.
3) Tannins: Tannins are carbon compounds. These are stored in different parts of the plant and are deep brown in colour. Tannins are used in tanning of leather and in medicines, e.g. Cassia, Acacia.
4) Resin: Occur mostly in Gymnosperms in specialized passages called resin passages. These are used in varnishes, e.g. Pinus.
5) Gums: Plants like Neem, Acacia oozes out a sticky substance called gum. When branches are cut. The gum swells by absorbing water and helps in the healing of damaged parts of a plant. Gums are economically valuable and used as adhesives and binding agents in the preparation of the medicines, food, etc.
6) Latex: Latex is a sticky, milky white substance secreted by plants. Latex is stored in latex cells or latex vessels. From the latex of Hevea braziliensis (Rubber plant) rub¬ber is prepared. Latex from Jatropa is the source of bio-diesel.
7) Modern chewing gum originally made of chick natural latex from plant.