What Are Plant Fibres and Why Are They Important in Biology?
Plant fibres are derived from plants. Plant fibres, also called fibre crops, are elongated thick-walled cells with pointed ends which consist of cellulose and may or may not contain lignin. Fibre Crops are grown for their fibres, 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. Fibres may be modified chemically like in viscose. There are different types of plant fibres like jute, flax, cotton, etc. Commercially, fibres are used in the textile industry for weaving the cloth, as a filtering medium, and also for insulation purposes.
Types of Fibre
Fibres obtained from various sources can be categorised as follows:
Plants fibres (Example: Jute, flax, cotton, hemp)
Animals fibres (Example: Silk, wool)
Regenerated and Synthetic fibres
i) Fibres generated from carbohydrate materials (Example: rayon).
ii) Fibres generated from protein materials (Example: Aridil from milk casein).
Mineral fibres (Example: Glass, asbestos)
Examples of Fibre 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 balls 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 utilised 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 sterilised by means of Gamma radiation.
Description
Colour - White (due to bleaching)
Odour - Odourless
Taste - Tasteless
Size Cotton fibres 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
First, Cotton fibres 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 colour
Ammoniacal copper oxide solution dissolves raw cotton fibres with the formation of balloons. While absorbent cotton dissolves completely with uniform swelling.
Cotton is insoluble in dilute sodium hydroxide solution and hydrochloric acid. It is soluble in 66 % of sulfuric acid.
Uses
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.
Storage
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.
Jute
Biological Source
It consists of phloem fibres of the stem of various species of the Corchorus (Corchorus olitorius and Corchorus capsularis Linn.) and Family Tiliaceae.
Chemical Constituents
The fibres are yellowish-brown in colour and contain cellulose (53%), hemicellulose (20%), and lignin (10 %).
Chemical Test
The middle lamella is highly lignified and gives a red colour with phloroglucinol and hydrochloric acid.
Uses
It is used in the manufacture of tows, padding splints, filtering, and straining mediums. Jute fibres are used for the preparation of coarse bags (Gunny bags).
Flax
Biological Source
These are pericyclic fibres obtained from the stem of the plant Linum usitatissimum belonging to family Linaceae.
Uses
The fibres were earlier used in the manufacture of lint, but at present cotton has replaced these fibres. It is used in the preparation of rugs, lace, lawn, and filtering medium.
Difference between Natural and Synthetic Fibre
Fibres are used as a raw material to make garments, clothes or any other applicational types of equipment. There are two types of fibres based upon the source of production. Natural fibres that are obtained from plants, animals or minerals and synthetic fibres that are obtained through chemical processes with the help of machines. Some of the examples of natural fibre include cotton, jute, silk, etc. And synthetic fibre includes polyester, Nylon, rayon, etc. However, there are a lot of differences between natural and synthetic fibres which are as follows:
Difference between Natural and Synthetic Fibre
Sample Questions
What are natural fibres?
What are plant fibres? give example
Differentiate between natural fibre and man-made fibre
What are the advantages of using natural fibre over man-made fibre?
Explain the type of fibre and give examples of each.
How is cotton prepared and what are its uses?
This was all about plant fibres. To learn more, access all the free resources available on the Vedantu website for the state board, CBSE, ICSE and competitive examinations.
FAQs on Plant Fibres: Types, Uses, and Key Examples
1. What are plant fibres?
Plant fibres are natural fibres that are sourced directly from different parts of plants. They are primarily composed of cellulose, a complex carbohydrate that provides structural support to the plant. These fibres are characterised by their length, strength, and flexibility, which makes them suitable for being spun into yarn and woven into fabric.
2. What are some common examples of plant fibres?
There is a wide variety of plant fibres used for different purposes. Some of the most common examples include:
- Cotton: Obtained from the fruit of the cotton plant.
- Jute: Sourced from the stem of the jute plant.
- Flax: Harvested from the stem of the flax plant, used to make linen.
- Coir: Extracted from the outer husk of a coconut.
- Hemp: Derived from the stem of the hemp plant.
- Sisal: Obtained from the leaves of the sisal plant.
3. From which parts of a plant are different fibres obtained?
Plant fibres are extracted from various parts of a plant, depending on the species. They can be categorised based on their origin:
- Seed/Fruit Fibres: These fibres are attached to the seeds or found in the fruit, like cotton and coir.
- Bast/Stem Fibres: These are found in the inner bark or stem of plants, such as jute, flax, and hemp.
- Leaf Fibres: These fibres are collected from the leaves of plants, with sisal and pineapple leaf fibre being common examples.
4. How is a raw plant fibre like cotton turned into a fabric?
The process of converting raw cotton into fabric involves several key steps as per the curriculum for the 2025-26 session. First, the process of ginning is used to separate the cotton fibres from the seeds. Next, these cleaned fibres are spun into yarn through a process called spinning, which twists the short fibres together to form a long, continuous thread. Finally, this yarn is used to create fabric through methods like weaving (interlacing two sets of yarn) or knitting (interlooping a single yarn).
5. What are the main uses of common plant fibres like jute and coir?
Jute and coir are known for their strength and durability, making them suitable for various industrial and household applications. Jute, often called the 'Golden Fibre', is primarily used to make sturdy sacks, bags, ropes, and carpets. Coir, being tough and water-resistant, is widely used for making doormats, brushes, floor mats, and stuffing for mattresses.
6. Why are cotton and jute the most commonly discussed plant fibres in the NCERT syllabus?
Cotton and jute are heavily featured in the NCERT syllabus due to their immense economic and historical significance in India. Cotton is the backbone of India's massive textile industry and has been cultivated for thousands of years. Jute is significant as a major cash crop, especially in eastern India (West Bengal, Assam), where its cultivation and processing provide livelihoods for millions. Their widespread use and importance make them ideal examples for teaching students about natural resources and industry.
7. Are all materials from plants considered fibres for making fabric?
No, not all plant-based materials can be used as textile fibres. To be suitable for making fabric, a fibre must possess specific properties like sufficient length, strength, flexibility, and fineness to be spun into yarn. For instance, wood is rich in cellulose, just like cotton, but its fibres are short and rigid, making them unsuitable for spinning into thread. In contrast, cotton fibres are long and soft, allowing them to be easily twisted into yarn.
8. Where are major fibre crops like cotton and jute grown in India?
The cultivation of these crops is concentrated in regions with suitable climatic and soil conditions. Cotton thrives in warm climates with black soil, making states like Gujarat, Maharashtra, and Telangana major producers. Jute requires alluvial soil and significant rainfall, so its cultivation is mainly concentrated in the Ganges delta region, including states like West Bengal, Assam, and Bihar.
