Author
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Riedell, Walter |
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Submitted to: Journal of Plant Nutrition
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/2/2015 Publication Date: 6/17/2016 Citation: Riedell, W.E. 2016. Growth and ion accumulation responses of four grass species to salinity. Journal of Plant Nutrition. 39:2115-2125. doi: 10.1080/01904167.2016.1193611. Interpretive Summary: Soil salinity appears to be intensifying on landscapes in the Northern Great Plains. The processes of salinization are reducing or eliminating all agricultural production on the affected areas. Because meeting the food and fiber needs of increasing human populations will depend upon increasing soil productivity on a global scale, management methods that prevent development or help ameliorate salt-affected soils are needed. Salt-affected soils can be reclaimed by the removal of water from deep within the plant root zone. This allows water derived from precipitation to percolate into the soil profile and carry soluble salts away from the soil surface. Removal of water from the soil profile can be accomplished through evapotranspiration of deep-rooted perennial vegetation. Thus, cultivation of salt-tolerant plants which remove water from the root zone can form the basis of a crop management approach to ameliorate salt-affected soils. The success of this management approach depends largely on the availability of plant species that germinate and grow well in salt-affected soils. Knowledge of the salinity tolerance mechanisms present in perennial grass plants may help establish germplasm screening methods useful in breeding plants that better tolerate salt-affected soils. Thus, the objective of this study was to investigate growth and ion accumulation responses to soil salinity in four perennial grass species. Technical Abstract: In plants, tolerance to saline environments can be achieved either through ion inclusion or ion exclusion. This greenhouse study measured shoot sodium (Na+), potassium (K+), and calcium (Ca2+) responses in four perennial grass species (tall wheatgrass, Nuttall's alkaligrass, creeping foxtail, and switchgrass) that were treated with nutrient solution salinity levels ranging from 2 to 32 dS m-1 (supplied as a 9:1 molar ratio of NaCl:Na2SO4) starting 28 days after planting (DAP) until shoot harvest at 68 DAP. Relative salinity tolerance, defined as the salinity level causing a 50% reduction in shoot dry weight, decreased in the order: tall wheatgrass > creeping foxtail >> switchgrass with Nuttall's alkaligrass intermediate between tall wheatgrass and creeping foxtail. As the nutrient solution salinity was increased from 2 to 10 dS m-1, tall wheatgrass, creeping foxtail and Nuttall's alkali grass had increased shoot Na+ and decreased Ca2+ concentration while maintaining growth suggesting that these species tolerated these changes in shoot ion concentration. In contrast, switchgrass excluded Na+ from the shoot and maintained shoot K+ and Ca2+ concentrations but suffered dramatic shoot dry weight reduction. Thus, the Na+ exclusion mechanisms present in switchgrass were less efficient in maintaining growth under the 10 dS m-1 nutrient solution treatment than the Na+ inclusion mechanisms used by the other three species. |
