ISSN:
1573-5036
Keywords:
Elytrigia
;
Epicuticular waxes
;
Halophytes
;
Leymus
;
Potassium
;
Roots
;
Salt tolerance
;
Shoots
;
Sodium
;
Transpiration
;
Triticum
;
Water use efficiency
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary In the first part of this review the main features of salt tolerance in higher plants are discussed. The hypothesis of intracellular compartmentation of solutes is used as a basis for models of tolerance mechanisms operating in roots and in leaves. Consideration is given to the implications of the various mechanisms for the yield potential of salt-tolerant crop plants. Some work on the more salt-tolerant members of the Triticeae is then described. The perennial speciesElytrigia juncea andLeymus sabulosus survive prolonged exposure to 250 mol m−3 NaCl, whereas the annual Triticum species are severely affected at only 100 mol m−3 NaCl. In the perennial species the tissue ion levels are controlled within narrow limits. In contrast, the more susceptible wheats accumulate far more sodium and chloride than is needed for osmotic adjustment, and the effects of salt stress increase with time of exposure. Two different types of salt tolerance are exhibited in plants capable of growing at high salinities. In succulent Chenopodiaceae, for example, osmotic adjustment is achieved mainly by accumulation of high levels of sodium and chloride in the shoots, accompanied by synthesis of substantial amounts of the compatible solute glycinebetaine. This combination of mechanisms allows high growth rates, in terms of both fresh and dry weight. At the opposite end of the spectrum of salt tolerance responses are the halophytic grasses, which strictly limit the influx of salts into the shoots, but suffer from very much reduced growth rates under saline conditions. Another variation is shown in those species that possess salt glands. The development and exploitation of crop plants for use on saline soils is discussed in relation to the implications of these various mechanisms.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02182231
