Salt Resistance

A complication of tire extension of tire electrolysis route for metal production, is tlrat in the case of the alkali metals, there is a significant solubility of the metal which would be produced by electrolysis in tire molten chloride. The dissolved metal provides very mobile electrons to tire melt, thus reducing the salt resistance, and dissipating the increased cuiTent, at a given applied potential, without the production of metal. To describe this phenomenon in... 

Metal-ammonia solutions reduce conjugated enones to saturated ketones and reductively cleave a-acetoxy ketones i.e. ketol acetates) to the unsubstituted ketones. In both cases the actual reduction product is the enolate salt of a saturated ketone this salt resists further reduction. If an alcohol is present in the reaction mixture, the enolate salt protonates and the resulting ketone is reduced further to a saturated alcohol. Linearly or cross-conjugated dienones are reduced to enones in the absence of a proton donor other than ammonia. The Birch reduction of unsaturated ketones to saturated alcohols was first reported by Wilds and Nelson using lithium as the reducing agent. This metal has been used almost exclusively by subsequent workers for the reduction of both unsaturated and saturated ketones. Calcium has been preferred for the reductive cleavage of ketol acetates. 

In spite of these difficulties the available data on crop performance (see Table 1) shows that the external concentration at which yield reduction becomes critical varies according to the crop. The approach to improving the salt resistance depends upon the external concentration at which improvement is sought. 

Salt damage is due to the product of xylem concentration and transpiration rate over the life of the leaf. There are several pathways for salt entry into the root. In spite of many reports in the literature of correlative associations between the lipid analyses of relatively crude root membrane preparations and salt resistance (see Kuiper, 1985), we have not been able... 

Table 2. Some physiological characters which affect salt resistance in rice...

Fig. 1. Relative composition of root microsomal membranes from 24 land races, varieties and breeding lines of rice which differ in their salt resistance. Campesterol, Stigmasterol and Sitosterol as % of total sterols 16 0, 18 1, 18 2 and 18 3 fatty acids as % of total fatty acids Na transport on a relative scale from (1) lowest to (9) highest. Data of D.R. Lachno, T.J. Flowers A.R. Yeo (unpublished).

Even a moderate quantity of salt reaching the leaves has a drastic effect on photosynthesis and leaf ultrastructure, much more than could be accounted for by the average tissue concentration (Flowers etal., 1985). Salt may accumulate in the apoplast (because it is not taken up fast enough by the cells of the leaf), and this would result in severe localised water deficit (Oertli, 1968). Differences in apoplast/protoplast balance are thought to be responsible for varietal differences in tissue salt load which can be accommodated (tissue tolerance Yeo Flowers, 1986). The xylem concentration of Na" is very much lower to young leaves than to older leaves (Yeo et al., 1985). This is advantageous in salt resistance because it means that at least some leaves are protected from salt, which otherwise causes premature leaf death (Yeo Flowers, 1984 Fig. 2). 

Varietal differences exist in all of these characteristics, and it is our theory that parents conferring the required traits should be combined. Depending on heritability and combining ability, we may add together genes for a number of useful characteristics, and a variety more resistant than any which has arisen by chance should be produced. Salt resistance is thus... 

Table 4. Salt resistance of plants regenerated from cell lines selected for tolerance of salt iir vitro...

Success in regenerating salt-resistant plants from salt-resistant cells has been limited (Table 4). The most extensively quoted example is the work of Nabors et al. (1980) who found that tobacco plants regenerated from NaCl-resistant cell lines survived salinity better than did plants regenerated from unselected lines. The authors themselves were justifiably cautious. 

A modified acrylamide polymer that is hydrophobically associating has remarkably improved the properties of salt resistance and temperature resistance, compared with high-molecular-weight polyacrylamide [1351]. 

Storey, R., and R. G. Wyn Jones. Quaternary ammonium compounds in plants in relation to salt resistance. Phytochemistry 1977 16 447-453. Krag, K. J. Plants used as contraceptives by the North American Indians. An ethnobotanic study. Thesis-by-Harvard University 1976 117 pp. Duehrssen, E., and K. H. Neumann. Characterization of satellite DNA of Daucus carota L. Z Pflanzenphysiol... 

Timberlake, C.F. and Bridle, P., Flavylium salts resistant to sulphur dioxide. Chem. Ind. 1489,... 

A mixture of a weak acid (or base) and its salt resists changes in pH caused by the addition of H+ or OH. The mixture thus functions as a buffer. 

Karlikanova, S. N., Ramazanov, I. U. and Ramazanova, D. R 1978. Production of salt-resistant mutants of lactic acid streptococci and their use in starters for pickled cheese. Twentieth International Dairy Congress. Brief Communication IE, 525-... 

Scheme VI. Processing of poly(t-BOC-styrene)-onium salt resists. The steps are (1) photogeneration of an extremely strong protonic acid from a triaryl-sulfonium or diaryliodonium salt and (2) baking, which allows acid-catalyzed deblocking of the t-BOC groups. Thus, irradiated areas of the polymer are converted to a much more polar form.

Shan et al. (2000) reported that flaxseed gum had good foamability, stability, emulsibility, and salt resistance, and that flaxseed gum has the... 

Portland cement pastes. Influence of composition on volume constancy and salt resistance. Ind. Eng. Chem., 26 1049-1060. 

Figure 1. Infrared spectrum of surface irradiated carbonate protected polyvinyl phenol/onium salt resist.

Dechat, T, Gotzmann, J., Stockinger, A., Harris, C.A., Talle, M.A., Siekierka, J.J. and Foisner, R. (1998) Detergent-salt resistance of LAP2alpha in interphase nuclei and phosphorylation-dependent association... 

Distillation equipment for soap-lye and esterification cmde requires salt-resistant metallurgy. The solid salt that results when glycerol is vaporized is removed by filtration or as bottoms from a wiped film evaporator. The Luwa scraped wall... 

Figure 3.30. SEMs of (top) positive and (bottom) negative J- xm images projection printed in a tertiary butyl ester-onium salt resist. Reproduced with permission from reference 105. Copyright 1986 Electrochemical Society.)...

---