Genetically controlled chemical

Genetically Controlled Chemical Factors Involved in Absorption and Transport of Iron by Plants... 

Chemical manipulation of secondary compound composition of crop plants offers several advantages over genetic control of their production. Chemical manipulation allows for timing the manipulation as well as possibly determining the quality and quantity of the desired response. 

The chemical composition of a glandular secretion may vary considerably between species. Very little is known yet on such differences in vertebrates, where known, it is not clear whether the differences are genetically controlled, the result of different diets or other ecological or phenotypical variation, or, finally, a combination of different factors. 

Williams, W., Harrison, J. E. M. and Jayasekera, S. 1984. Genetic control of alkaloid production in Lupinus mutabilis on the effect of a mutant alle mutal isolated following chemical mutagenesis. Euphytica, 33 811-817. 

Another consequence of the genetic control of activating systems is that people cam be expected to differ in their constellations of enzymes, and therefore in their susceptibility to mutagens. Some examples are known, but this field is in its infancy. It would be desirable to take account of the fact that some chemicals that cure nonmutagenic for most people may be highly mutagenic for a few. It is not yet possible to gauge this sensitivity, but it is very likely to be an important part of the mutation protection of the future. 

Plant use of iron depends on the plant s ability to respond chemically to iron stress. This response causes the roots to release H+ and deduct ants, to reduce Fe3+, and to accumulate citrate, making iron available to the plant. Reduction sites are principally in the young lateral roots. Azide, arsenate, zinc, copper, and chelating agents may interfere with use of iron. Chemical reactions induced by iron stress affect nitrate reductase activity, use of iron from Fe3+ phosphate and Fe3+ chelate, and tolerance of plants to heavy metals. The iron stress-response mechanism is adaptive and genetically controlled, making it possible to tailor plants to grow under conditions of iron stress. 

Some of the chemical factors involved in the mechanism of iron absorption and transport in plants have been established. These reactions are genetically controlled, which makes it possible to select or develop iron-efficient plants for use in soil that causes iron stress. In addition we need to know ... 

In a previous section, data and plots were given showing the rapid rise in consumption and production of manufactured fibers at the expense of natural fibers. The principal reason for this has been the wide range of manufactured fiber variants that can be produced from a single fiber-forming polymer. The wide range of polymers available, each with its particular properties, adds yet another dimension. This is not to say that there is only one type of cotton, wool, silk, or asbestos fiber there are many varieties of natural fibers, but their supply is limited by natural factors such as climate and genetics. The relative availabilities of manufactured fiber types can be altered by controlled chemical-process... 

Because of the ease of qualitative analysis, first through distillation to isolate major components and, subsequently, through GLC, volatile oils have consistently attracted the attention of chemotaxonomists. These oils are almost invariably complex mixtures in which monoterpenes and/or sesquiterpenes usually predominate, although the bios)mthetically unrelated phenylpropanes can also be important. Some of the earliest studies on the genetic control of SM involved the oils of mints, Mentha (Murray, 1960). Volatile oils yielded the first properly documented examples of chemical races (Penfold and Morrison, 1927 Sutherland and Park, 1967), while Zavarin and co-workers (1971) provided clear evidence for the impact of environmental factors on the composition of volatile oil. Because of the comparative nature of GLG analysis, volatile oils were among the first compounds to be extensively studied at the population level and to be subjected to numerical analysis. The work of Adams on Juniperus in south-eastern USA... 

---