Plants ethylene effect

It should also be noted that there are some producers that have used the concept in this chapter where the chlorine production is combined with EDC production. The VCM plant would then be designed in the so-called unbalanced mode where the feedstocks are EDC and ethylene, not chlorine and ethylene. Effectively, all of the chlorine and one-half of the ethylene come into the unbalanced VCM plant as EDC. Frequently, the reason for this strategy is that EDC is very much easier and safer to store and transport than liquid chlorine. An additional important reason for this configuration is that chlorine can then be produced economically in areas of low-cost power. Often, these are the very same areas where low-cost ethylene is also available. Examples of areas of both low-cost power and low-cost ethylene are the United States Gulf Coast (see Fig. 21.4) and the Middle East. 

Farmer, 2001). Even nectar production may be effected by such hormones (Heil et al, 2001). The gaseous hormone ethylene plays an important role in plant development, but also in defense (Mattoo and Suttle, 1991). Upon perception of a pathogen, plants show enhanced ethylene production, which has been shown to be involved in the induction of defense reactions (Boiler, 1991). Wild tobacco plants engineered with an Arabidopsis sp. ethylene-insensitive gene do not show typical leaf development arrestment in the presence of leaves of other tobacco plants, demonstrating the importance of ethylene in plant development (Knoester et al.,... 

Ethylene as a stimulator of growth and development. The most observed actions of ethylene on growing plants involves growth inhibition, or acceleration of senescence. These actions are especially evident in the antagonism or opposition of ethylene to auxins, gibberellins and cytokinins (27), as already outlined above. Actually ethylene stimulates growth in many types of cells, especially in water plants (Table II). When ethylene acts to stimulate cell elongation, as in water plants, auxins and CC>2 enhance the ethylene effect (38,39). This interaction is the reverse of that observed on land plants wherein ethylene opposes the effects of auxin, GA3 and cytokinins. 

Carbon dioxide is, of course, fundamentally important to plants because of photosynthesis. Most plant cell cultures are heterotrophic, non-photosynthetic and use a chemical energy source. It is reasonable to suspect, however, that some of the control mechanisms for the photosynthetic dark reactions would be regulated by C02 concentration. This could affect both cell growth and, indirectly, production of useful compounds. More concretely, C02 is known to promote synthesis of ethylene [38] on the other hand, C02 concentrations of 5-10% inhibit many ethylene effects [53]. 

Pallas, J.E. and Kays, S.J., Inhibition of photosynthesis by ethylene a stomatal effect, Plant Physiol., 70, 598-601, 1982. 

Theologis, A. and Laties, G.G., Potentiating effect of pure oxygen on the enhancement of respiration by ethylene in plant storage organs a comparative study, Plant Physiol., 69, 1031-1035, 1982a. 

Effective plant defense requires coordination of direct and indirect defenses such that they do not interfere or even act synergistically. A relevant example comes from studies by Baldwin, 8 who wondered why the nicotine defense of wild tobacco is downregulated by an ethylene burst following attack by young tobacco hornworm larvae. He formulated three — as yet untested — hypotheses to explain this. 

One option is to close just part of a plant in order to reduce capacity. A European chemical company shut down 20 percent of an ethylene derivative plant, cutting the planfs fixed costs by 20 percent and its personnel by 15 percent. The company was then able to find a merchant buyer for the ethylene that was produced. Despite the closing and severance costs that the company incurred and the effect on its ethylene business, the partial closure raised the facility s net present value by 35 percent. 

Table I. Effects of Applied Ethylene on Plants and Plant Parts Compared with Similar and Dissimilar Effects of Auxins (5, 67)...

Although these data call into question ethylene s present position as the do it in almost all plant hormone, there is no denying the manifold effects of applied ethylene in plant growth and development. For many years ethylene itself has been used commercially to elicit some of these effects, for example, fruit ripening. Compounds which initiate ethylene responses by inducing the plant to produce its own ethylene (a wound response) have been used in the field. Cycloheximide application, for example, stimulates abscission of citrus by stimulating ethylene production at the button [15]. The possibilities for harnessing ethylene responses in... 

Goldschmidt EE, Aharoni Y, Eilati SK, Riov JW, Monselise SP (1977) Differential counteraction of ethylene effects by gibberellin A3 and N -benzyladenine in senescing citrus peel. Plant Physiol 59 193-195... 

Mayak S, Dilley DR (1976) Regulation of senescence in carnation Dianthus caryophyl-lus) Effect of abscisic acid and carbon dioxide on ethylene production. Plant Physiol 58 663-665... 

Tal M, Imber D, Erez A, Epstein E (1979) Abnormal stomatal behavior and hormonal balance in flacca, a wilty mutant of tomato. V. Effect of abscisic acid on indoleacetic acid metabolism and ethylene evolution. Plant Physiol (Bethesda) 63 1044-1048 Taylorson RB, Hendricks SB (1977) Dormancy in seeds. Annu Rev Plant Physiol 28 331-354... 

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