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The Epidermis of flowering plants
produces a wide array of hairs or Trichomes. They range
from simple cells to elaborate,multi cellular, organ-like structures. Their adaptive
significance is truly great, and many of their features are crucial for life on land. In
some cases the relationship between plants and animals, as well as microbes is mediated by
epidermal hairs. Young leaves are often covered with Trichomes. These may be ephemeral or
persistent. They provide protection for these primordial structures, but in most
cases the true nature of their effects are unknown. |
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The most familiar, and most simple
Trichomes are root hairs! These are under-appreciated
in terms of their functional significance. They are single cells! that greatly increase
the absorptive surface area of roots. The most notorious interrelationship of root hairs
and microbes occurs in the legume-Rhizobium symbiosis. The root hairs are the
initial recognition sites for the attachment of the nitrogen-fixing bacteria.
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 Dehiscent Cotton Fruit - The ovary wall has reflexed to reveal the tightly packed cotton fibers. |
 Mature, Expanded Cotton Fruit showing the profusion of fibers. |
The most important plant textile is cotton. Cotton fibers are gigantic cells. They are produced by the Epidermis of the Ovule. The ovule becomes the seed. The adaptive value of the fibers is probably due to enhanced seed dispersal. The fibers are pure cellulose and are ideal for the production of clothing. | |
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The strength of cotton fibers is due to the alternating layers of highly organized cellulose which have opposing pitches. | ||
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Cross-section of a cotton fiber showing the
laminated nature of the cell wall. The genus of cotton is Gossypium. |
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Hawaiian cotton has been used to introduce valuable genes into commercial lines. This shows the potential genetic value of rare species. | ||
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