Plant Fibres

What Are Fiber Crops

Plant fibers are derived from plants. Plant fibers, also called fibers crops are elongated thick-walled cells with pointed ends which consist of cellulose and may or may not contain lignin.  Fiber crops are grown for their fibers, which are used for making paper, rope, and cloth. In medical practice, they are used as a surgical dressing made up of natural or artificial materials. Fibers may be modified chemically like in viscose. There are different types of plant fibers like jute, flax, cotton, etc. Commercially, fibers are used in the textile industry for weaving the cloth, as a filtering medium, and also for insulation purposes.

Types Of Fiber 

Fibers obtained from various sources can be categorized as follows:

  1. Plants fibers (Example: Jute, flax, cotton, hemp)

  2. Animals fibers (Example: Silk, wool) 

  3. Regenerated and Synthetic fibers 

  1. Fibers generated from carbohydrate materials (Example: rayon). 

  2. Fibers generated from protein materials (Example: Aridil from milk casein).

  1. Mineral fibers (Example: Glass, asbestos)

Examples Of Fiber Crops

  • Cotton

  • Biological Source

Cotton consists of the epidermal trichomes or hairs of the seeds of cultivated species of the Gossypium (Gossypium herbaceum, Gossypium barbadense ), belonging to the family Malvaceae. 

Preparation of Absorbent Cotton

After flowering, the plant bears fruits which are known as capsules. The fruits are 3 to 5 cells. Each capsule contains numerous seeds. The hairs from which seeds are covered are known as bolls. Then these bolls are collected and dried and taken to the ginning press. Various devices separate the hairs. Linters are the hairs with a short length which are used for the manufacture of absorbent cotton. While long hairs are utilized for the cloth preparation. After mixing with a soda ash solution, it is put under pressure for about 10-15 hours. It is then treated with a suitable bleaching agent after washing it with water. Then it is dried and carded into flat sheets.   Finally, it is packed in wrappers. Afterward, it is sterilized by means of Gamma radiations. 


  • Color - White (due to bleaching)

  • Odor - Odorless 

  • Taste - Tasteless 

  • Size Cotton fibers are 2.5 - 4.5 cm, in length, and 25 - 35 diameters.  

Chemical Constituents 

Raw cotton contains about 90% of cellulose, 7 to 8% of moisture, wax, fat, and remains of protoplasm.  Purified cotton or absorbent cotton comes with 6 - 7 % of moisture and is entirely cellulose.

Chemical Tests

  1. At first, Cotton fibers are soaked in iodine water and then dried.  Then the addition of few ml.  of 80% sulfuric acid trichomes which assume the purplish-blue or bluish-green color 

  2. Ammoniacal copper oxide solution dissolves raw cotton fibers with the formation of balloons. While absorbent cotton dissolves completely with uniform swelling.

  3. Cotton is insoluble in dilute sodium hydroxide solution and hydrochloric acid.  It is soluble in 66 % of sulfuric acid.


Cotton is used as a filtering medium in surgical dressings and also as an insulating material.  Cotton absorbs blood, mucus, pus and it prevents wounds from infections.  


Absorbent cotton should be stored in a cool place. Cotton is made friable and brittle by the bacterial contamination.  The absorbent cotton should be wrapped in wrappers to avoid dust and microbial contamination. Heat and long storage make absorbent cotton non-absorbent. 

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Biological Source

It consists of phloem fibers of the stem of various species of the Corchorus (Corchorus olitorius and Corchorus capsularis Linn.) and Family Tiliaceae. 

Chemical Constituents 

The fibers are yellowish-brown in color and contain cellulose (53%), hemicellulose (20%), and lignin (10 %). 

Chemical Test 

The middle lamella is highly lignified and gives a red color with phloroglucinol and hydrochloric acid.


It is used in the manufacture of tows, padding splints, filtering, and straining medium. Jute fibers are used for the preparation of coarse bags (Gunny bags).  

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Biological Source 

These are pericyclic fibers obtained from the stem of the plant Linum usitatissimum belonging to family Linaceae.


The fibers were earlier used in the manufacture of lint, but at present cotton has replaced these fibers.  It is used in the preparation of rugs, lace, lawn, and filtering medium.

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FAQ (Frequently Asked Questions)

1. What are the Geographical Sources of Flax, Jute, and Cotton

  • Geographical Source of Flax

The annual herb is cultivated in many countries like Argentina, Russia, Canada, India, Holland, and the USA.  The seeds of the plant are a good source of fixed oil and mucilage which is also used medicinally.  

  • Geographical Source of Jute

The plants producing jute are cultivated in West Bengal, in the basins of Ganges and in Assam.  The jute plants grow successfully in areas having loamy alluvial soil with pH values ​​of 6 to 8. 

  • Geographical Source of Cotton

In the USA, Egypt and India cotton is produced commercially. It is also cultivated in various parts of Africa and South America. In India, 7 million hectares of land are under cultivation of cotton.

2. Which Fibers are Obtained From the Stem of the Plant?

There are few fibers that are obtained from the stem of the plant. The base of vegetable fibers is cellulose which is a structural material in the plant world. This is the reason that plant fibers are generally made of cellulose and may or may not contain lignin. Examples include cotton, hemp, jute, flax, ramie, sisal, and bagasse, etc. Plant/vegetable fibers are obtained from plant sources such as cotton which is obtained from the seed of the cotton plant and jute which is obtained from the jute plant's stem, from the outer covering of coconut fruit from which coir is obtained.