Figure - On the day of anthesis numerous fiber initials develop primarily at the chalazal end of the ovule. (J. McD. Stewart)
Figure 42. Secondary wall synthesis is affected by temperature; thus, daily fluctuations in temperature produce a ring-like appearance in the wall that can be viewed using DIC (light microscopy) when the wall is swollen. (C.H. Haigler)
Figure -. LM section through an ovule, showing array of fibers on the outside. (R.W. Seagull)
Figure -. As fibers mature, the secondary walls thicken, thus increasing micronaire. Mature fibers can exhibit a range of micronaire values, depending on wall thickness. Panels A, B and C exhibit increasing micronaire values from 6.5,. Note that fibers with thinner walls have lower micronaire values. (E. Boyleston)
Cotton Fiber Development Quiz
1. The ________________ is the most economically relevant part of the cotton plant.
seed
linters
mature dried fiber
seed oil
2. The growing of the cotton plant and the development of fiber are controlled by the _________________.
biological processes
sunlight
water
chemistries
3. The final step in the production of cotton fiber is ____________.
pollination
germination
budding
opening of the boll
4. Which of the following are cotton fiber qualities?
length
strength
micronaire
all the above
5. Fiber development begins when the ________________ is about to open.
seed
flower
boll
none of the above
6. The outer wall coating of a cotton fiber is referred to as the _____________ .
epucle
cuticle
lumen
windings
7. The outer wall is coated with a waxy membrane and is composed of cellulose _____________.
micronaire
metals
polycarbons
microfibrils
8. As the fiber grows, new components are inserted into the cell wall and membrane. Because this new material is deposited throughout the length of the fiber, this type of cell expansion is called __________ growth.
diffuse
obtuse
elongation
primary
9. Accompanying the increases in fiber length and diameter is the development of a rigid ______________ inside the fiber wall.
cuticle
lumen
protoplasm
secondary cell wall
10. Also, inside the fiber outer walls is the _____________ which is filled with nutrients and protoplasm.
cuticle
lumen
secondary cell wall
none of the above
11. The transition from primary to secondary wall production is marked by the deposition of a thin layer of wall material called the ___________.
winding layer
cuticle layer
helix layer
all the above
12. Secondary wall synthesis is affected by ______________; thus, daily fluctuations produce a ‘ring-like’ appearance in the wall.
time
protoplasm
temperature
none of the above
13. The mature fiber, before it dries, appears as a long cylinder. After drying the fibers collapse, producing _______________ structure.
a flattened, twisted ribbon
a mostly flat oval shaped
a tri-lobal, twisted ribbon
a spiraling cylinder
14. If the fiber does not produce a thick secondary wall, the fiber is said to be_______.
dormant
deceased
mature
immature
15. Normally, dried cotton fibers exhibit a _____________ shape which aids in the formation of yarns and fabrics.
thin, cylindrical ribbon
thick, cylindrical ribbon
thin, flattened ribbon
thick, flattened ribbon
16. As fibers mature, the secondary walls thicken, thus increasing the __________.