Exam 4 - All Chapters

Cellulose, lignin

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, 2^nd to 3^rd 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

1. After the first encounter with an allergen, IgE antibodies are produced and attach to the surface of basophils and mast cells

2. 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