Freezing resistance and carbohydrate composition of 'Floratam' St. Augustinegrass
1991
Fry, J.D. | Lang, N.S. | Clifton, R.G.P.
'Floratam' St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] stolons were sampled from the field between October and March to determine potential changes in lethal low temperatures and nonstructural carbohydrate composition. Lethal temperatures determined by electrolyte leakage ranged from -6.1 to -5.3C. Little variability in lethal temperatures over sampling dates indicated that 'Floratam' St. Augustinegrass did not readily acclimate to cold temperatures. Starch was the carbohydrate present in highest concentration in 'Floratam' stolons, with levels ranging from 7.7 to 12.4 mg/100 mg dry weight. Sucrose concentrations varied from 2.4 to 5.7 mg/100 mg dry weight. Glucose and fructose were also present in 'Floratam' stolons at lower concentrations. A slight increase in sucrose and decrease in starch were observed between November and December, when low temperatures resulted in chlorophyll loss and turf was <25% green. On all other sampling dates, changes in sucrose and starch were variable. Changes in concentration of total nonstructural carbohydrates or soluble sugars did not seem to influence the freezing resistance of 'Floratam' St. Augustinegrass.
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