Sodium plant tolerance

Chandler, S.F. Thorpe, T.A. (1987). Characterization of growth, water relations, and proline accumulation in sodium sulfate tolerant callus of Brassica napus L. cv. Westar (Canola). Plant Physiology, 84, 106-11. 

Solid alkalis Solid alkalis may be used, in principle, for the corrosion control of drum boilers at all pressures but other factors, e.g. carryover or hideout a (reversible disappearance from solution on-load), may preclude them in some cases. However, they are used for feed-line treatment only in lower pressure plant where the boiler has increased tolerance to the higher solids burden which their use entails. Sodium hydroxide or, at very low pressures, sodium carbonate, (which is hydrolysed to the hydroxide at boiler temperatures) have been used, as have potassium and lithium hydroxides and various phosphate mixtures. (For a comparison of various alkalis for this purpose see References.)... 

This chapter deals with sodium a-olefinsulfonate (AOS) and with sodium internal olefmsulfonate (IOS). AOS is a well-established product and is being applied in many household and industrial formulations. IOS of a sufficiently high quality has only recently been made on laboratory scale and pilot plant scale and has not yet been applied in commercial formulations. AOS and IOS have not only good wetting and detergency properties, but also good tolerance toward water hardness ions, a combination not always observed for other anionic surfactants. 

A more significant body of literature focuses on the use of protoplasts in understanding processes related to stress tolerance. The role of Ca in salt toleranee has been evaluated using maize root protoplasts. Exposure of the plasmalemma directly to external media revealed a non-specific replacement of Ca by salt. Sodium was found to replace Ca though this could be reversed by adding more Ca (Lynch, Cramer Lauchli, 1987). This approach assists in understanding the role of specific ion interaction in enhancing salt tolerance and is potentially applicable to studies on the molecular basis for ion specificity of plant membranes. 

Bajaj, Y.P.S. Gupta, R.K. (1986). Different tolerance of callus cultures of Pennisetum americanum L. and P. purpureum Shum. to sodium chloride. Journal of Plant Physiology, 125, 491-5. 

Bhaskaran, S., Smith, R.H. Schertz, K.F. (1986). Progeny screening of sorghum plants regenerated from sodium chloride-selected callus for salt tolerance. Journal of Plant Physiology, 122, 205-10. 

Phytoextraction is mainly carried out by certain plants called hyperaccumulators, which absorb unusually large amounts of metals compared to other plants. A hyperaccumulator is a plant species capable of accumulating 100 times more metal than a common nonaccumulating plant. Therefore, a hyperaccumulator will concentrate more than 1000 mg/kg or 0.1% (dry weight) of Co, Cu, Cr, or Pb, or 10,000 mg/kg (1%) of Zn and Ni (dry matter).43-44 Similarly, halophytes are plants that can tolerate and, in many cases, accumulate large amounts of salt (typically sodium chloride but also Ca and Mg chlorides). Hyperaccumulators and halophytes may be selected and planted at a site based on the type of metals or salts present, the concentrations of these constituents, and other site conditions. 

Tolerance of and/or dependence upon socEurn chloride can be an important consideration in the survival of plants and aquatic animals. This depends upon osmotic regulation rather than sodium specificity. 

Both salinity and sodicity impair plant growth and reduce agricultural yields. In severe cases, they can cause complete crop failure (Qadir et al. 2000). Plants on saline areas suffer from lack of water, because salts bind water in the soil and thus make it inaccessible to plants and microorganisms. Beside this osmotic stress situation, an excess of specific ions, such as sodium, is toxic to plants or results in an ion imbalance, which complicates the uptake of specific nutrients (Marschner 1995). Some crops have developed tolerance to salty conditions and can thus be used to a certain extent on soils affected by salinity. 

Effluents from sewage treatment plants are not allowed to contain residual chlorine in excess of tolerable values as determined by water quality standards. For example, in discharges to trout streams, the residual chlorine should not exceed 0.02 mg/L. Thus, chlorinated effluents should be dechlorinated. Sulfur dioxide, sodium sulfite, sodium metabisullite, and activated carbon have been used for dechlorination. Because sulfur dioxide, sodium sulfite, and sodium metabisulfite contain sulfur, we will call them sulfur dechlorinating agents. Dechlorination is an oxidation-reduction reaction. The chemical reactions involved in dechlorination are discussed next. 

Plants are cleaned, sanitized, and rinsed immediately after processing, and right before processing to ensure satisfactory initial process conditions from microbiological standpoint [3]. Because chlorine is freely permeable to most membranes that it is able to sanitize the permeate side of the system as well as the retentate side, using solutions of sodium hypochlorite containing 100-200 ppm of active chlorine is a common sanitation technique for many membranes, except cellulose acetate reverse osmosis membranes, which can only tolerate brief exposure to chlorine at 10-50 ppm level [3]. 

Olt et al. introduced Na NMR micro imaging to map the sodium distribution in living plants. The experiments were performed at 11.71 T with a double resonant Na- H probe-head. The Na micro imaging promises great potential for physiological studies of the consequences of salt stress on the macroscopic level and thus may become a unique tool for characterizing plants with respect to salt tolerance and salt sensitivity. 

AtHKTl was identified as a regulator of Na influx in plant roots. This conclusion was based on the capacity of hktl mutants to suppress Na" accumulation and sodium hypersensitivity in a sos3 (salt-overly-sensi-tive) mutant background [31], suggesting that AtHKTl is a salt-tolerance determinant that controls the entry of Na into the roots. 

Tab. 1.2-10 Plant species without response to sodium fertilization and low salt tolerance, and those with good response and high salt tolerance...

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