Soluble carbohydrates in two buffalograss cultivars with contrasting freezing tolerance

No information is available regarding endogenous soluble carbohydrate accumulation in buffalograss [Buchloe dactyloides (Nutt.) Engelm.] during cold acclimation. The objective of this study was to determine composition of soluble carbohydrates and their relationship to freezing tolerance in two buffalograss cultivars, 609 and NE 91-118, with different freezing tolerances. The experiment was conducted under natural cold acclimation conditions in two consecutive years in Fort Collins, Colo. Based upon average LT50 (subfreezing temperature resulting in 50% mortality) from seven sampling intervals in 1998-99 and six sampling intervals in 1999-2000, 'NE 91-118' survived 4.5 degreesC and 4.9 degreesC colder temperatures than '609', during the 1998-1999 and 1999-2000 winter seasons, respectively. Glucose, fructose, sucrose, and raffinose were found in both cultivars in both years, and were generally higher in acclimated than pre- and post-acclimated stolons. Stachyose was not present in sufficient quantities for quantification. Cultivar NE 91-118 contained 63% to 77% more glucose and 41% to 51% more raffinose than '609' in the 1998-99 and 1999-2000 winter seasons, respectively. In 1999-2000, fructose content in 'NE 91-118' was significantly higher than that of '609'. A significant negative correlation was found between LT50 vs. all carbohydrates in 1999-2000, and LT50 vs. sucrose and raffinose in 1998-99. Results suggest that soluble carbohydrates are important in freezing tolerance of buffalograss.