Promoters, modifiers, and inhibitors

neutral organic compounds, and/or other promoters and inhibitors, 

inorganic compounds, such as nitrate and multivalent cations, 

soil physical characteristics, such as pH, temperature, aeration, and soil moisture, 

biotic processes such as microbial utilization and synthesis and root exudation, secretions, and uptake, 

Balke ME (1985) Effects of aUelochemicals on mineral uptake and associated physiological processes. In Thompson AC (ed) The chemistry of allelopathy. Biochemictil interactions timong plants. ACS symposium series, vol 268. American Chemical Society, Washington, DC, pp 161-178 

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Much effort has been devoted during the last 30 years toward understanding the mechanisms operative in the coordination catalysis of ethylene and a-olefin polymerization using Ziegler-Natta systems (metal halide and aluminum alkyl, sometimes with Lewis base modifiers). Aspects of the complex heterogeneous reactions have been elucidated (jL- ) but the intimate mechanistic detail - for example the role of inhibitors and promoters, kinetics and thermodynamics of chain growth, modes of chain transfer and termination - comes primarily from studies of homogeneous catalysts ... 

Disperse oxides unmodified or modified by organics (OC) or OSC are used as fillers, adsorbents, or additives [1-11]. OSCs are used as promoters of adhesion, inhibitors of corrosion, for the stabilization of monodisperse oxides and the formation of the nanoscaled particles. Oxide modification by alcohols or other OC is of interest for synthesis of polymer fillers, as such modification leads to plasticization and reinforcement of the filled coating, but in this case a question arises about hydrolyz-ability of the =M—O—C bonds between oxide surface and alkoxy groups, as those are less stable than =M—O— M= formed, for example, upon the silica modification by silanes or siloxanes. The high dispersity, high specific surface area, and high adsorption ability of fumed oxides have an influence on their efficiency as fillers of polymer systems. 

While the bulk of any cyanoacrylate formulation consists of monomer, a large number of modifiers have been used to impart desired properties to the composition. These include stabilizers, inhibitors, thickeners, plasticizers, dyes or colorants, adhesion promoters, and others. Each of these classes of modifier will be dealt with in subsequent parts of this chapter. Because of the variety of modifiers, and the variety of applications for cyanoacrylates, a bewildering number of cyanoacrylate adhesives are now commercially available. These can be generally divided into the following classifications adhesives of different viscosities and cure rates, adhesives based on different monomers, adhesives for the bonding of metal, plastic, rubber, or wood, various types of improved performance adhesives, i.e., heat, moisture, or impact resistant, and adhesives for bonding low surface... 

These organic promoters and inhibitors must be at sufficient concentrations and be present for sufficient length of time to modify plant function and growth of receiving plants either directly (e.g., impact on root membranes and/or cell process) or indirectly (e.g., impact on nodule or mycorrhizae formation,... 

Germination and radicle/hypocotyl growth of weed seeds are modified by many physical and chemical characteristics of soil extracts such as presence, concentrations, and activities of promoters and inhibitors, pH, solute potential, and organic... 

However, if phenolic acid from tissues are primarily utilized ( used up ) to stimulate phenolic-acid utilizing microbes within the bulk soil and/or the rhi-zosphere/rhizoplane, then the inhibition of cucumber seedlings could be due to a promoter/modifier/inhibitor complex dominated by other inhibitors and any remaining phenolic acids and phenolic acid breakdown products, and... 

These organic promoters and inhibitors must be at sufficient concentrations and be present for a sufficient length of time to modify plant function and growth of the receiving plant. 

In general, then, we may view the auxins and GA s as promoters of cell elongation and ABA and ethylene as inhibitors. The cytokinins act as promoters of leaf cell expansion and inhibitors of stem elongation. This is somewhat oversimplified in light of the aforementioned exceptions, and the evidence that effects of applied hormones are often modified by or mediated by other hormones. 

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