A good portion of our cultural baggage includes technology and this requires the use of natural materials for applications other than food. The most basic and ancient human tools required attachment - binding for arrows and lances - and this required a fibrous material. Also, we are a warm-climate species. Expansion of human populations from our point of origin - the Old World tropics - required protection from the cold via fibrous material. Thus, some domsticated species that are used for fiber are of ancient, old world origin and, because they were among the first to be brought 'into the camp', have multiple uses.

Classification of fibers:

Plant vs. Animal vs. synthetic

Animal: (sheep, camels, vicunas, guanacos, some goats and rabbits, and the silk moth) - all are animal fibers than can be twined or spun and composed of protein, polymer of amino acids - much more complex than cellulose - will denature (no heat), has more flexibility and dye retention, and more susceptible to pests (more attractive food resource than cellulose).

Plant: cellulose, polymer of glucose - polysaccharide - molecules cross-linked to one another - basic material to the cell wall - a feature unique to the plant kingdom and NOT present in animals.

Synthetic: produced from petroleum, cheaper (at this point in time), less complex structurally.

Types of plant fibers:

Botanical:

1. A specific type of cell - thick cell wall, elongate, typically present in the vascular bundle of stems and leaves - associated with the phloem

2. A tissue type - bundles or strands of fiber cells that function in the vascular system to protect the living cells of the cambium and phloem [sieve tube elements and companion cells]

Functional:

      1) bast (stem-phloem of dicots)

      2) leaf (vascular bundles from monocot [usually] leaves)

      3) fruit and seed

Bast (Stem) Fibers:

Flax - Linum usitatissimum - (Linaceae) - no wild species - origin uncertain - med. basis - used by swiss lake dwellers 10K BP, Egyptian (mummies) - 5K BP - Greeks and Romans (our word 'line' and generic name Linum derived for latin word for flax fiber. A true 'bast' fiber (from phloem) - crop used for both fiber and linseed oil in old days - now cultivars selected for each use. Fibers are naturally smooth, straight, and 2-3X longer than cotton - ascendency of cotton economic - machine processed - flax worked by hand - takes time - fine linen too expensive for most folks.

Hemp - Cannabis sativa (Cannabaceae-note also hops from this family) - initially spread around the world as a fiber crop - probably originated in western asia (Afganistan) - 6K BC in china [also grown for its seed - oil] - 1st century AD in Med. Basin - ususally used for cordage, rope, canvas, and sailcloth - Levi Strauss made 1st Levis with hemp cloth - (check book - how did the names 'jeans' and 'denims' originate?] - major item of US culture and world trade.

Leaf Fibers:

Sisal - Agave sisalana (Agavaceae) - Mexican, central American - fiber of the Mayans and Aztecs - big advantage - producing something useful from arid regions of the world - also pulque, tequila also from Agave.

Abaca, Manila hemp - Musa textilis (Musaceae) also M. paradisiaca [banana] - leaf fiber taken from long petioles - largest herbs, rhizomes, etc. - special properties and many uses: tea bags, dollar bills, 'manila envelopes, filter tips, etc.

Exam Info: around 5 main questions, each will provide a choice of at least 3 'sub-questions' to select for response - essay [put down ALL you know] or short-answer response. Focus on Angiosperms (structure, reproduction, classification) and fibers - especially Cotton - see sample from 1993

Coir - Cocos nucifera - (Arecaceae or Palmae) - derived from thick, fibrous mesocarp [adapted for sea dispersal, thus resistant to sea water) - [fig. 16.13 in text] used in netting - not a good fiber - its use mainly based on ready supply of mesocarps from COPRA production - largest angiopserm seed - endosperm initially liquid (milk), as it matures, cell walls form around the nuclei and it solidifies as an oil-rich 'meat' around the testa - mounds bars

Luffa acutangula and L. cylindrica: - luffa - demonstrate unusual vascular system - another Cucurbitaceae - retting

Processing:

Retting: mostly for bast fiber, timed or controlled rotting to remove or disintegrate non-fibrous materials which are associated with the stem [cortex, pith] and vascular bundles [cambium, phloem]

Scutching: roll retted material to break the brittle woody material, then remove woody material (thick-walled xylem cells) by beating and scraping

Hackling: drawing scutched and retted material across a comb-like device to separate and align fibers

Decorticating: crushing and scraping to remove fibers in lieu of above, used mostly in leaf fibers

Ginning: unique to seed fibers, removal of the seeds

Fiber from Seeds: use blow gun: wood (gun barrel, darts), gum (stuff used to bind), cordage (vine bark used as wrapping), and fiber for attachment of gourd and (probably from Kapok (Ceiba - Bombacaceae), tropical tree, seed fiber, too fine to spin) - for packing. Note: ancient device - no DOMESTICATED plants involved - from with wild.

Wild cotton seeds are 'comose' with a covering of short hairs [linters] which are single cells that emerge from the surface [epidermis] of the testa or seed coat. Human selection has functioned to elongate these hairs [staples]. Domesticated species have both - linters are processed out and used in paper making

Gossypium (Malvaceae) - about 40 species with centers of diversity in Australia, southern Asia, Africa and the New World - two centers of domestication - Africa and south-central Asia (5, 000 BP in Pakistan), Mexico (ca. 6,000 BP), and South America (initial use ca. 10,000 BP, evidence of domestication ca. 4,500 BP). Genus studied cytologically by J. O Beasley of TAMU (Beasley Cotton Genetics Lab on Agronomy Road) - he defined GENOMES of Cotton

African/Asian ('Old World') cottons: G. arboreum and G. herbaceum - both diploids - 2n = 2x = 26 (Beasley genome AA) - origin unknown, possibly domesticated independently, early use in south-central asia with spread throughout the Near East and Europe by 1400s. Mostly replaced by New World cotton species, now grown primarily in India and Pakistan.

    Australian diploid wild cottons - Beasley genome CC

    Mexican/South American wild diploids - Beasley genome DD

Tetraploids: (AADD):

    South American Cotton: G. barbadense - tetraploid 2n=4x=52

    Mexican Cotton: G. hirsutum - tetraploid 2n=4x=52 (95% of world crop - species grown in Texas)

Mystery of Cotton - one of the genomes of the tetraploid cottons is that of G. herbaceum - an old world species (genome AA) - how did this happen? (review tetraploidy)

An ancient genus that has diploid species in Africa, Australia, and the Americas - divergence between these three groups evidently occurred as a result of long-distance dispersal.[genus age is ca. 24-33 my - most recent continuous distribution with Africa and Australia is 130-120 my - Gondwana supercontinent] - current notion: Either African genome (A) was present in South America and went extinct or (more likely) - seeds traveled from Africa to South America, hybridized with South American diploids (DD) - chromosome doubling (AADD) to produce the tetraploids, with the parential AA diploid going extinct.

Henna - Lawsonia inermis (Lythraceae) - dye with affinity to protein - use by Greeks and Romans as a hair darkener - still used as a base for hair colorants.

Safflower - Carthamus tinctorius (Asteraceae) - ancient dye plant that is still used

British 'Redcoats' of the American Revolution - 'madder' - Rubia tinctoria (Rubiaceae) - contains natural mordants

Annatto - Bixa orellana (Bixaceae) - red dye used originally as a hair-coloring paste, body paint and fabric dye by native Americans of the amazon lowlands now used as a coloring agent for margarine, cheese, and cosmetics.