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Cellulose, lignin
examples of plant fiber cells
Commercial Fibers
Stringy, elongated masses of plant material
Collection of fiber cells or entire vascular bundles
Tensile Strength
resistance to tearing apart when subjected to tension
Higher Quality Fibers
higher in cellulose (high tensile strength)
Lower quality fibers
higher in lignin, browner, less strenth
Textile, Cordage, Filling Fibers
Most common fiber uses
Natural fibers
Fibers sourced from plants, animals, and/or minerals (cellulose, protein, and asbestos respectively)
Synthetic Fibers
fibers sourced from wood pulp (rayon)
Surface Fibers
fibers that cover seeds, leaves, or fruit (ex: cotton)
Bast/Soft Fibers
clusters of phloem fibers, inner bark or dicot stems (ex: linen)
Hard/Leaf Fibers
Fibers found in the vascular bundles of leaves, cells of xylem, phloem, fibers. Monocot leaves are higher in lignin (ex: manilla hemp and pina)
Ginning
extraction process in which surface of the fibers are torn lose, often done by machine
Retting
extraction process in which soft fibers are freed from stems by microbial action
Decortication
extraction process in which unwanted tissues are scraped away from hard fibers
Spinning
Method of yarn formation in which fibers are cleaned, stretched, laid parallel, and then twisted together to form yarn. Finished yarn can then be woven into cloth.
Can be done by hand, but more often done by spindle.
Cotton
Most popular natural fiber, makes of 50% of the world’s textiles.
Surface fiber extracted from seed coat
Origins of Cotton Plant
Asia, Africa, Central and South America, and Australia
Cotton Plant
Shrubby plant with palmately compound leaves. Annual in temperate areas, but perennial in the tropics
Boll
Cotton fruit, capsule with fibers on seed coats.
Up to 20,000 hairs per seed.
Hairs assist in wind dispersal by enabling the seeds to be airborne.
Each seed hair is a single coat cell
Cotton Gin
Eli Whitney’s 1973 invention for harvesting cotton bolls/fibers. Increased production from 1 pound per day (by hand) to 50 pounds per day. Made cotton significantly more profitable.
Cotton Processing
After fiber is ginned, it is packed into large bales
Ramifications of Cotton Gin
Increase in demand for slave labor, causing continued growth up to the civil war in 1861
Bleaching
Traditional method was to soak fibers in sour milk and cow’s dung, then steep in lye, then a buttermilk bath, before washing them then laying them to dry outdoors in the sun.
Modern method is to use chlorine.
Mercerization
Finishing method in which the cotton is placed in a bath of caustic soda, causing the fibers to swell into a round shape. This made them stronger, more lustrous, and possess a greater affinity for dyes
Permanent Press
Finishing method that results in a shape-retentive finish. Chemicals used cross-link the fibers. The resulting fabric has memory and needs little to no ironing.
Bollgard
Bioengineered cotton hybrid containing Bt toxin, an insecticide effective against cotton bollworm, pink bollworm, spotted bollworm, and tobacco budworm. It reduces pesticide usage and increases crop yield.
Genes from bioengineered cotton plants found in wild cotton in Mexico, with the nearest source more than 2000 km away.
Negative Effects of Bioengineered Cotton
Plants with herbicide resistance gene produce less nectar, meaning ants are less drawn to the plant and are no longer there to protect the plant from herbivores.
Plants with insecticide gene produced too much nectar, attracting too many ants, overrunning the plant and deterring potential pollinators.
Linen
Blast/Soft fiber made from flax. Fibers are used to make cordage (30,000 year old European fibers) or cloth (6,500 year old cloth from Egypt). Only two types of flax are grown commercially, one for seeds and oil (linseed oil) and the other is for fibers.
Fibers are extracted through a retting process. Can take from 4-6 weeks (dew), to 1 to 3 weeks (pond or streams), or as little as a few hours in a tank with chemicals.
Linen Fabrics
Naturally lustrous, strong, and durable. Often used for clothing, upholstery, drapes, and towels, as it draws moisture.
Fabric does lack elasticity and is prone to wrinkling
Jute
Annual, native to wet tropical Asia
Mainly grown in India and Bangladesh
Blast fibers from 1.5 to 6 meters
Stems retted to free fibers
Yellow to brown in color, difficult to bleach
Weak fibers; break easily – higher in lignin, which means lower in cellulose
Examples: burlap, wall coverings, ropes, carpet backing, upholstery lining, sackcloth
Hemp
Dark brown, blast fibers, processing similar to flax (retting)
Longest fibers up to 2 meters
Industrial fibers, canvas, ropes, twine
Canvas from Cannabis
Original Levi Strass jeans used hemp cloth
Serge de Nims, France (Cloth of Nimes) became denim
Industrial hemp used in sailing ships, covered wagons
Grassroots movement to revitalize hemp fiber industry
2019 Agricultural Improvement Act (Farm Bill)
Legal to grow industrial hemp if THC levels are less 0.3 percent
Manilla Hemp
Fibers from large petioles, can be up to five meters (15) in length.
Most used to make marine rope, but other uses include: lightweight clothing, teabags, and cigarette filters
Pina (Pineapple Cloth)
Fibers are taken from the leaves of the pineapple plant, can be 5 to 10 cm long. Fibers create a fine, soft, lustrous cloth, the traditional apparel of the Philippines
Coir
Seed fiber from coconuts (falls into surface fibers category). Fibers are dark brown and difficult to bleach. Coarse but durable, often used to make ropes and floor mats.
Rayon
Artificial silk, a synthetic fiber composed of cellulose. It has low strength and elasticity, meaning that it wrinkles and stretches easily. It has good moisture absorbency and is easy to dye.
Current Threats to Forests
Deforestation
Forest Fires/Climate Change
Introduced pests/pathogens
Examples include the Chestnut Blight and Dutch Elm Disease
30%
Percent of the Earth’s surface covered by forests that supply wood
Wood
Secondary xylem used to move water throughout the plant. Cell wall materials (cellulose and lignin) are high in strength and durability.
Hardwoods
Angiosperm trees, denser than gymnosperm trees
Softwoods
gymnosperm trees, less dense than angiosperm trees. Examples include Pines and Douglas Fir, which are light but strong.
Hardness
The amount of lignin in the cell walls and the density of the wood
Heartwood
Centermost rings in a tree. Functions in support but is no longer active in transport. It is darker due to the accumulation of tannins, gums, and resins that help to prevent decay—preferred for lumber.
Sapwood
Lighter wood outside the heartwood. It functions in both support and transport/conduction.
United States and Canada
Leading lumber producing countries
Home construction
Greatest use of softwood lumber
Oak
Most economically important hardwoods in the USA
Veneer
A very thin sheet of a desired wood that is glued to a base of less expensive lumber - providing the look of fine wood at a lower cost.
Plywood
Three or more layers of thick veneer glued together, creating a board stronger than a comparable solid wood. The grains of alternate layers are perpendicular to each other. Most common sources are douglas fir and pine.
Plants and Musical Instruments
Almost all cultures and music, and plant-based materials have been used in musical instruments since earliest times
Early percussion instruments include dried gourds used as rattles and sticks struck together.
Gourds were later used as drums, several types of wind instruments and string instruments
Early wind instruments include hollow stems of bamboo and reeds.
Reeds, especially the giant reed, were later used in flute like instruments and pan pipes
Arundo donax is best kwon as the source of the reeds used in woodwind instruments
Spruce with a straight grain is usually used for the top plate of a violin
Maple is used for the bottom plate
Wood quality affects sound vibration
50%
The amount of the world’s harvested wood that goes to fuel. Up until recently, wood served as the chief source of fuel for human cultures. The majority of wood used in developing nations is used as fuel, with over 2 billion people depending on wood or charcoal for 90% of their energy needs.
Charcoal
Fuel source made from wood through partial combustion with restricted airflow, developed over 7000 years ago. It burns at a much higher temperature than wood.
It can be used to smelt ores into metals, which ushered in the age of metals (copper, bronze, iron)
Wood Pellets
Often burned in stoves or boilers, but can also be burned in power plants, as an attempt to lower carbon emissions by replacing coal with a renewable resource.
Does come with questionable ecological value due to CO2 emissions during transportation and processing, deforestation, end their emissions when burnt.
Resin
A broad collection of compounds that are produced by many trees. They discourage herbivores and make the wood resistant to some decay-causing fungi.
Best known come from conifers, which produce it in ducts throughout the tree
Pitch
Commercial term for the crude exudate collected in resin harvesting.
Rosin
What is left behind after pitch is heated, used by baseball players and by string musicians on their bowstrings
When pitch is heated, volatile components evaporate and then condense as turpentine
Turpentine
The condensed product resulting from pitch being heated, which causes the volatile components to evaporate and then condense
Cork
When trees increase in diameter, periderm replaces the epidermis
The major component is cork, of phellem, produced by the cork cambium
Cork cell walls contain suberin
During early Greek and Roman times, cork was used to seal bottles and casks and also used for flotation devices
Commercial sources of cork are from the bark of the evergreen oak
The outer bark is stripped from the tree about every ten years
Paper
USA accounts for over 1/3 of the world's production and use of paper and paper products, ranking second behind China
In the US, about 38% of the wood that is harvested is used to manufacture 75 million metric tons of paper and paper products.
Paper consumption has declined
Paper products have increased
Cardboard boxes
Early writing surfaces
Sumerians (5000 years ago) used clay tablets
Egyptians (4500 years ago) use papyrus
Papyrus, is a sedge that grows naturally in Egypt, Ethiopia, the Jordan River valley, and Sicily
Made from thin slices of pith (from stem) beaten flat, then crosswise layers added
Moistened, pressed to flatten, then dried
Modern Papermaking
Most paper is prepared from wood pulp
Wood pulp is a watery suspension of pulverized wood containing tracheids, vessels, and fibers in hardwood pulp
Just tracheids in softwood pulp
Processing removes the lignin
The Fourdrinier paper machine:
Pulp is deposited onto a moving wire screen
Water drains through the screen
Leaves a mat of fibers that make up a sheet of paper
Alternatives to wood pulp
Cotton and linen
Recycled denim
Fibers from agricultural waste
Hemp
Recycled paper
Soaked in water to release pulp fibers
2020: 66% of paper and 89% of cardboard was recycled (USA)
37% of paper production comes from recycled materials
Poisonous Plants
Plants that can adversely affect the health of humans/animals, but may have medicinal value at very low doses. Poisons develop to protect the plant from grazing animals, herbivores, and insects
Can be used in hunting (arrow poison) and poisoning enemies (lists from 3500 bCE and Ancient Greece use for capital punishment)
Carrot Family
large perennial herbs with some poisonous plants
Poison hemlock
Plant in the carrot family, with pinnately compound, highly dissected, fern like leaves. It also has a compound umbel of tiny white flowers and a hollow grooved stem with purple blotches
Poison present in Poison Hemlock
Coniine, an alkaloid that can cause creeping paralysis from the lower limbs upward
Used as capital punishment in Ancient Greece
Water Hemlock
A member of the carrot family found in wet or swampy areas with pinnately compound leaves, and coarsely toothed leaflets. It has a compound umbel of tiny white flowers.
Poison present in Water Hemlock
Alcohol cicutoxin, which causes violent convulsions. The highest concentration is in the yellow sap of the roots.
Giant Hogweed
Gigantic invasive herb in the Carrot family. It can reach up to 4.6 meters high, with leaves 1.5 meters wide, and a stem 5-10 cm in diameter.
Leaves are alternate, pinnately compounded, and have three lobed toothed leaflets. The stem has nodes with coarse white hairs, and reddish purple blotches
poison present in Giant Hogweed
Phototoxic sap that causes phytophotodermatitis when exposed to UV-A wavelength of light. This causes skin cell death, blisters, 2nd to 3rd degree burns, permanent brown stains, and scaring
Pokeweed
a large herbaceous perennial, native to eastern North America. All parts of the plant are poisonous.
Their berries have been used to make ink and dye
Poison present in Pokeweed
Two toxic glycosides (Phytolaccigenin and phytoaccatoxin) that can cause sever gastrointestinal distress and vomitting.
Mitogen, which can cause abnormal cell division in red blood cells leading to clots, heart attacks, and strokes.
Poison can be absorbed through skin legions
Milkweeds
Common weeds with opposite or whorled leaves, follicle fruited, and silk-tufted seeds.
Poison in Milkweed
Cardioactive glycosides in a resinous gliotoxin cause spasms
Toxic Food Chain
A defense mechanism developed by monarchs in which caterpillars feed on milkweeds and pass glycosides on to the adult butterfly. When birds eat the butterfly, they become ill.
Rhododendrons, azaleas, and laurels
Broadleaf shrubs in the heath family. Their leaves, pollen, and nectar are all poisonous
Poison in Rhododendrons, azaleas, and laurels
Grayanotoxanes stimulate, then block, nervous regulation of the heart. Poisoning can be caused by the consumption of honey made from nectar.
Tea from leaves of mountain laurel were used to make suicide potion by the Delaware Nation
Philodendron
Poisonous houseplants in the Aroids family that has vines or erect stems and heart shaped leaves
Dumbcane
Poisonous houseplants in the Aroids family with white-speckled leaves on erect tsmes
Poison in Aroid family
Fruits contain calcium oxalate crystals that cause painfull swelling of mouth, tongue, and throat if swallowed. This can lead to difficulty talking, swallowing, and breathing.
Toxic proteins can intensify this pain and lead to edema
Alleopathy
The phenomenon where certain plants release chemicals that inhibit the growth of other nearby plants, affecting their development and survival. It is common in desert ecosystems, but present in many plants
Antigen
Anything that triggers an immune response. This can be an invading pathogen or a small part or product of that organisms.
Allergens
The specific term for antigens that are otherwise harmless such as pollen, fungal spores, cat dander, etc.
Types of allergies relating to plants
Respiratory, contact dermatitis, food
Antibodies (immunoglobins)
The body’s response to a foreign substance. They are composed of four polypeptide, each with a variable region that provides the antibody with the ability to counteract a specific antigen
IgE Antibody
The antibody produced in high levels by people with allergies
Progression of an Alergic Reaction
After the first encounter with an allergen, IgE antibodies are produced and attach to the surface of basophils and mast cells
When the allergen is encountered again, it will bind to the IgE molecules
This binding causes the release of histamine and other chemicals that are responsible for allergy symptoms
Basophils
A type of cell that circulates in the blood
Mast Cells
Cells that line the surface of the respiratory tract, intestines, and skin
20 to 25%
The percentage of the human population that has one or more allergies
Hay Fever (allergic rhinitis)
One of the most common allergies. It has immediate hypersensitivity and symptoms include, sneezing, runny nose, nasal congestion, watery and itchy eyes, and itchy years
Asthma
One of the two most common allergies, an episode can be triggered by an allergen, viral infection, stress, or exercise. Symptoms include the inflammation of the airways, bronchial constriction, and excessive mucous secretion
Hay Fever plants
Plants that produce high quantities of lightweight pollen that is dispersed by wind. That pollen is then deposited in the nasal passages of one’s upper respiratory tract triggering an allergic response.
Ragweed
the most common hay fever plant
Spring Hay Fever Plants
Tree pollen is normally considered the leading cause as the inconspicuous flower (or male cones) appear early in the season, often before the leaves develop
Summer hay fever plants
Grasses are the leading cause as many native grasses pollinate in late spring or summer, though some species of lawn grass, such as Bermuda grass, will continue to flower throughout the growing season
Fall hay fever plants
Weeds constitute an artificial category of hay fever plants that include non-grass and non-tree species. Ragweed pollen is the most important allergen in this category. Other common weeds are allergens pollinating in summer and fall are sagebrush, lambs quarters, plantain
How Climate Change impacts allergy plants
Climate change has changed the growing season of plants, and long term pollen records show earlier start dates for pollen season. There is also evidence of increased pollen levels and fall has increased in duration.
Contact dermatitis
A delayed hypersensitive allergic reaction of the skin to something touched. A rash takes up to 24 to 48 hours to appear.
Poison ivy, poison oak, poison sumac
Common examples of contact dermatitis plants
Urushiol
The resinous allergen in contact dermatitis plants, it binds to proteins in skin and is spread via rubbing and scratching
50% (~10%)
The percent of the population allergic to contact dermatitis plants and the percent with sensitivities so severe that they might require medical care if exposed
Locations of food allergy symptoms
gastrointestinal tract, skin, or respiratory tract
10% and 8%
Percent of adults and children in USA with food allergies, respectively