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Measurement and Interpretation of Salinity Tolerance in Four Perennial Grasses

Kopittke, Peter M., Kopittke, Rosemary A., Menzies, Neal W.
Journal of plant nutrition 2009 v.32 no.1-3 pp. 30-43
Poaceae, perennials, salt tolerance, sodium chloride, salt stress, salinity, dry matter accumulation, forage grasses, forage crops, regression analysis
Whilst the topic of soil salinity has received a substantive research effort over the years, the accurate measurement and interpretation of salinity tolerance data remain problematic. The tolerance of four perennial grass species (non-halophytes) to sodium chloride (NaCl) dominated salinity was determined in a free-flowing sand culture system. Although the salinity tolerance of non-halophytes is often represented by the threshold salinity model (bent-stick model), none of the species in the current study displayed any observable salinity threshold. Further, the observed yield decrease was not linear as suggested by the model. On re-examination of earlier datasets, we conclude that the threshold salinity model does not adequately describe the physiological processes limiting growth of non-halophytes in saline soils. Therefore, the use of the threshold salinity model is not recommended for non-halophytes, but rather, a model which more accurately reflects the physiological response observed in these saline soils, such as an exponential regression curve.