Physiological Effects of the Combined Stresses of Freeze-thaw, Acid Precipitation and Deicing Salt on Alfalfa Seedlings

Abstract

BackgroundIn the early spring of northern China, the combined stresses of freeze-thaw, deicing salt and acid deposition are the main ecological threats to the urban turf ecosystem. ResultsWe studied changes in the Malondialdehyde (MDA), protein, soluble sugar, proline and chlorophyll contents of DongMu No. 1seedlings of 8 treatment combination groups which are imposed by freeze-thaw (F), acid rain (A) and deicing salt (D). An increasing in MDA content showed that the membrane system of seedlings was damaged under combined stress (F+A+D). The changes indicated that under the adverse conditions, the proline and soluble sugar contents increased obviously with the accumulation of MDA in the plants, while the chlorophyll content decreased significantly.ConclusionPlants can alleviate the damage caused by stress by increasing soluble sugars and by regulating the proline content to maintain osmotic balance.