not Only the food of plants but also their wastes are useful to us. What evidences do you give for it?

Explanation

1) The secondary metabolites are the materials which do not require for normal growth and developments.
2) Examples for the secondary metabolites are alkaloids, Tannins , Resins , Gums and Latex.
3) Alkaloids are nitrogenous by - products and poisonous. They are stored in differ- ent parts of the plant.
4) The alkaloids secreted by plants and their uses are :
a) Quinine is used as antimalarial drug.
b) Nicotine is used as insecticide.
c) Morphine and cocaine are used as pain killers.
d) Reserpine is used as medicine for snake bite.
e) Caffeine is used as stimulant for central nervous system.
f) Nimbin is used as antiseptic.
g) Scopolamine is used as sedative.
5) Tannins are carbon compounds which are deep brown in colour. Tannins are used in tanning of leather and in medicines. e.g. : Cassia , Acacia.
6) Resins occur mostly in Gymnosperms in specialized passages called resin pas-sages. They are used in varnishes. e.g. : Pinus.
7) When branches of trees are cut a sticky substance called gum is secreted. The gum swells by absorbing water and helps in the healing of damaged parts of a plant. e.g. : Neem, Acacia.
8) Economically gums are valuable , being used as adhesives and binding agents in the preparation of the medicines, food etc.
9) Latex is a sticky, white substance secreted by paints. Latex is stored in latex cells or latex vessels.
10) From the latex of Heavea braziliensis (Rubber plant) rubber is prepared. Latex from Jatropa is the source of bio-diesel.