 |
|
Cinchona
flowers
The flowers are yellow or pink
coloured that are borne in terminal panicles. They are produced from the third or fourth year
of growth. Cross-pollination takes place in the flower. The inflorescence of the flower is
kept on display. |
| Cinchona fruits
The fruits are capsule which are
septicidal and is exhibited in the Drug show-case of the Economic Botany Gallery. |
 |
| Dyes
A dye is a material used for
colouring textiles. Many plant produces have been used from ancient times for dying textiles.
Indigo, turmeric, kamala, chay roots and catchu are some example of
vegetable dyes and are still of commercial importance. Vegetable dye stuffs are extracted by
the process of fermentation, boiling, and treatment with chemicals. Various shades may be
obtained from a single dye by the use of different mordents with which the fabrics to be dyed
are treated.
Many vegetable dyes have been now superseded
by synthetic dyes such as aniline, alizarin, and other products of coal-tar.
|
| 
|
Indigofera tinctoria
Indian Indigo
This plant belongs to the
family 'Fabaceae'. It forms the principal source of the industry and called as the 'King of
dyestuffs'. It was grown in India, China and other eastern countries. The people of Asia had
known the dyes for over 4,000 years. The leaves of the plant contain a soluble odourless
glycoside, called 'Indican'; during fermentation of the leaves indican is hydrolysed to
glucose and indoxyl. Indigotin is obtained as a result of oxidation of indoxyl. If the dye is
of high quality, it is deep violet-blue and porous.
The dye is used in dyeing and printing
cotton fabrics, rayon and wool. It is used in washing of cotton clothes. It is also used in
the manufacture of pigments for printing inks, lacquers and paints.
|
|
Tannins
'Tannins' are complex
organic compounds chiefly 'glucosidal' in nature which have an acid reaction and are very
astringent; their biological function is uncertain; may be concerned with the formation of
rock or pigment. Economically tannins are important because of their ability to unite with
certain type of protein such as those in animal skin to form a strong flexible, resistance and
insoluble structure called the 'Leather'. They also react with the salt of iron to form a dark
blue or greenish black compound which forms the base of common inks. Tannin materials are
often used in oil drilling to reduce the viscosity of the oil without reducing its specific
gravity. Tannin is commonly found in cell, sap, bark, wood, leaves, roots, fruit galls and
leaf galls. The tanning industry is a very old industry and dates back to 5,000 years. The
Chinese tanned the leather even 3,000 years back and the Romans used the oak bark for tanning
the skin.
Terminalia bellerica
(Belleric Myrobalan - Kadukkai (Tamil))
A large deciduous tree, common in the plains and lower hills
throught India. It belongs to the family 'Combretaceae'. The fruit of this plant is exported
from India, for tanning, as a mordant and also for medicinal use.
|
|
|
|
|
Economic
Botany