Sodium chloride tolerance of selected herbaceous perennials and the effects of sodium chloride on osmotic adjustment and ionic uptake in three species of herbaceous perennials.

摘要

Thirty-eight species of plants were screened in a greenhouse for tolerance to soil applied sodium chloride solution. Five were able to grow under the highest salt level applied, twenty-four were rated highly sensitive to moderately sensitive and the remaining species were rated moderately tolerant.; Three species were then selected based upon varying salt tolerances and further studies were conducted in the field and growth chambers. Armeria maritima was determined to be highly salt tolerant. There were no visual symptoms, and neither height nor width changed during any experiment. Armeria was also able to lower its osmotic potential. This species also took up large quantities of Na+, which was found in the leaf tissue.{09}Finally, Armeria was able to continue uptake of K+ in the presence of Na+, as there was little change in the amount of K+ found in leaf tissue.; Leucanthemum xsuperbum showed a wide range of visual symptoms, including marginal necrosis, complete leaf death, death of the apical meristem, wilting of foliage, change in foliage color and death. Monarda didyma developed marginal necrosis, which rapidly progressed until the entire plant was killed.; Sodium was not found to any great degree in either Leucanthemum or in Monarda. Neither of the latter two species was able to continue K+ uptake under salt stress. Calcium levels remained unaffected in all three species. Neither Leucanthemum nor Monarda was able to lower osmotic potential. Based upon the results of this study, it is likely these two species were killed due to osmotic problems and not through specific ionic effects.; Soil samples were also collected from the field plot and analyzed for changes in texture, bulk density, electrical conductivity, and concentrations of Na+, K+ and Ca2+. There were no statistical changes in either bulk density or soil texture. The general trend for bulk density however, was for it to increase as salt concentration increased. Soil samples taken in the high salt plots showed higher levels of Na+, and decreased levels of both K+ and Ca2+. Electrical conductivity was also greater in the salt-affected areas than in control plots.