Cotton maturity

A typical chemical composition of native cotton is given in Table 25.4 [12]. The main constituent is cellulose. Some other materials, such as waxes, pectin, sugars, organic acid, protein, and so forth, are also present. The relative amount of pectins and other noncellulosic substances reduce as the cotton matures [12]. 

Fiber samples collected from the various textile plants were tested by the NIR and microscopic methods. The relationship between the two sets of data is shown in Figure 25.11, where agreement was excellent with =. 97. NIR cotton maturity tests were performed on four varieties of cotton during their various stages of growth as illustrated in Table 25.5. This method of determining cotton maturity provides a technique for textile manufacturing to quickly detect cotton samples that could create quality problems in textile products. 

E. Lord, The Origin and Assessment of Cotton Fiber Maturity, 2nd ed.. The International Institute for Cotton, Manchester, UK, 1982. 

The germination stimulant or stimulants from host plants have not yet been identified, but research on isolation and identification of these allelopathic compounds continues. Other nonhost plants, such as cotton, also release chemicals which stimulate the germination of witchweed seed and these crops can replace the cereal crops in witchweed-infected fields. If no acceptable host is present, the witchweed plant is unable to mature and produce seed. The importance of cereal crops as a staple food in underdeveloped countries makes growth of nonhost crops only partially acceptable, and there are numerous wild hosts that allow the witchweed to germinate, mature, and produce more seed (several thousand seeds can be produced by a single plant). Nevertheless, application of either natural or synthetic stimulants in the absence of a host plant is an effective way of reducing and eventually eliminating the witchweed problem. 

Research studies concluded that diets containing 200 ppm or less of free gossypol as cotton-seed meal was safe for Holstein calves. At 400 ppm, there was an increase in cardiovascular and lung lesions, leading to increased calf losses. Mature beef cows can be safely fed cotton-seed meal as their entire protein supplement as this is generally kept relatively low, whereas dairy cows should not receive more than 3.6 kg/head/day (reviewed by Cheeke, 1998). 

In his analysis of parts of mature cotton plants. Brown (18) reported constituents in roots, stem, leaves, bolls, seed and lint. In Table III, I have listed his values for leaves and lint which are among the principle components of unglnned cotton. 

Chemical Analysis of Leaf and Lint Parts of Mature (percent dry basis) Cotton Plants ... 

The Mississippi cotton was much more difficult to wet out than either the California or Texas cottons. This is apparently related to the nature of noncelluloslc constituents on the fiber surfaces. The Mississippi cotton was a mature, low noncellulose content cotton, whereas, both the California and Texas cottons had high noncellulose contents. The ratio of wax content to total noncellulosics was much higher for the Mississippi cotton than for either the California or Texas cottons. The surface of the Mississippi cotton is thus more hydrophobic and resists wetting, Levels of extractables and dust levels are summarized in Table VIII. 

Part of the silicon is most likely a soil contaminant on the surface of the bracts while most of the other major elements detected are known to be plant nutrients. Silicon and silicates have been detected in a number of other plant mater ials (37,38). The plant nutrients nitrogen, phosphorous and potassium have been reported as a function of the maturity of cotton plants (39). 

Fly Cotton. It consists mostly of dead or unripe cotton fibers from plants which have not reached maturity as a consequence of attacks by parasites, genetic factors or lack of nutriment. The fibers collect into tangled masses called "neps". Dead fibers may be recognized in cotton from the fact that they are doubly refractive, showing colors under a polarized microscope. If a mica plate is... 

Purified cotton consists of the fibers of different cultivated varieties of Gossypium sp. The material is freed from adhering impurities, deprived of fatty matter, bleached, and sterilized. The length of cotton fibers is up to about 5 cm, the diameter varies between 9 to 25 pm. A typical cotton fiber is cylindrical when young, but becomes flattened and twisted as it matures. The genuine cellulose wall of the cotton fiber is covered with a waxy cuticule. Delipidation is essential in order to transform the genuine fiber to absorbent cotton wool which is readily wetted by water. 

Dead Cotton. This name is given to unripe fibers of cotton having very thin walls. These fibers have died before reaching maturity as a consequence of attacks by parasites, genetic factors or competition for nutriment. Such fibers are less easily nitrated or acetated than ripe cotton and constitute a large proportion of the "fly which passes into cotton waste... 

In some cases, however, cotton fibres appear like thin flattened ribbons with a peculiar transparency and with occasional bruised bends (Fig. 70, Plate VI). This is so-called dead cotton and is due to faulty cultivation or to incomplete maturation. 

Twenty-seven two-year-old scaleless hens were transported to Visalia, CA on October 1, 1979, housed in cages overnight with food and water provided ad lib, and exposed to field applications of DEF on October 2. Some birds were repeatedly treated over the next five days. The mature cotton fields (Diversified Farming Inc.) were sprayed from a ground vehicle that treated 8 rows simultaneously with DEF-6 (0.72 kg/l, 6 lb/gal Mobay Chemical Co.) at 0.37 gal/acre and Accelerate (amine salt of endothall (7-oxabicyclo (2.2.1) heptane-2,3-dicarboxylic acid, 0.06 kg/l, 0.5 lbs/gal) at 0.19 gal/acre in 25 gal water/acre. 

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