Bamboo and Fibers

Question 1

Bamboo classification

Answer 1

• Subfamily of grass family Poaceae
• Approx. 1000 species in 90 genera
• Monocot, produced by primary growth
• Has no secondary growth (as for wood)

Question 2

Bamboo Plants

Answer 2

• Up to 40m high, 30cm diameter
• Can grow up to 60-90cm a day
• Rigid stalk
• Culm: hollow jointed stem - segmented tube
• Sprout from underground rhizome
• Most make new stalks every year
• High fiber, has lignin (w/o secondary growth)
• Flower at long intervals, 30-60 years

Question 3

Bamboo flowering

Answer 3

• long intervals, 30- 60 years
• One species flower at the same time, even at different locations
• Because same genetic make up even if geographically separated

Question 4

Human use of bamboo

Answer 4

• Hollow culms are light and strong
• Many similar functions as wood
• Food, structure, furniture, containers, musical instruments, paper

Question 5

Plant Fibers

Answer 5

• Used as woven material
• One of the most useful plant materials
• Composed chiefly of cellulose

Question 6

Cellulose

Answer 6

• Scaffold of secondary cell walls
• Polysaccharide of glucose units
• Very strong
• Needs to be separated from other plant cell material to be used

Question 7

How is cellulose separated from other plant cell material?

Answer 7

• Mechanical process like ginning, or retting in moisture

Question 8

Properties of useful plant fibres?

Answer 8

• Can be spun
• Strength and durability
• Absorbency

Question 9

Types of plant fibers

Answer 9

• Surface fiber
• Bast (soft) fibres
• Leaf (hard) fibres

Question 10

Leaf (hard) fibers

Answer 10

• Mostly from fast growing tropical monocots
• Manila hemp, Musa textilis, Musaceae, banana family
• Have to ‘scrape’ to get fibre
• Money bills, tea bags, manila envelopes

Question 11

Flax

Answer 11

• Linum usitatissimum, Linaceae
• Linen cloth
• Stronger than cotton, shiny, rounder fibres
• Considered oldest textile fibre
• Swiss lake dwellers 10,000 years ago, used it for mummy cloth

Question 12

Bast (soft) fibres

Answer 12

• Hemp
• Jute
• Flax

Question 13

Jute

Answer 13

• Corchorus capsularis, Malvaceae

- Most used bast fibre

Question 14

Hemp

Answer 14

• Cannabis sativa, Cannabaceae
• Fast growing, one of the earliest plants cultivated
• Long fibre used for rope and canvas
• Blue jeans originally made from hemp

Question 15

Cotton Plant

Answer 15

• Gossypium hirsutum, Malvaceae, cotton family
• Many species w/ various geographic origins (maybe Asia)
• Most widely used plant fibre
• Significant non-food crop
• Fibers coat seeds for airborne dispersal
• Large amount of fibre per plant

Question 16

Why is cotton good for spinning and why does the plant produce so much fibre?

Answer 16

• Hollow, long and twisted

- Produces large amount of fibre to coat seeds for airborne dispersal

Question 17

Cotton Harvesting

Answer 17

• Originally very labour intensive
• Separating lint from seeds
• Eli Whitney invented mechanical gin in 1793 in US that increased efficiency 50x over doing by hand

Question 18

Cotton production in the US

Answer 18

• Boomed in US south as demand grew in Europe
• US export to Britain from first bale in 1784 to 40 million bales in 1861
• Led to resurgence of slavery

Question 19

Cotton and Slavery

Answer 19

• Demand led to resurgence of slavery
• 1850, close to half population black slaves in the south, most worked cotton and some other crops
• US civil war btwn north and south over issue of slavery, 1861-65, 600000 dead

Question 20

Growing Cotton and genetic modification

Answer 20

• Heavily genetically modified
• Cotton subject to heavy loss by insect pests
• Bt cotton created by Monsanto contains insecticidal toxin from bacterium Bacillus thuringiensis
• insect damage high in India and chemical insecticides expensive, therefore Bt cotton is only approved GM crop in India

Question 21

Where is the majority of cotton produced now?

Answer 21

• China