Predicting relative low-temperature tolerance of non-acclimatized buffalograss using calorimetric data

No information is available regarding the usefulness of calorimetry in assessing freeze tolerance, cold hardiness and associated mechanisms in turfgrass. In this study, isothermal and scanning microcalorimetric techniques were used to determine relative low-temperature tolerance and freezing points of leaf and root segments of three, non-acclimatized buffalograss (Buchloe dactyloides (Nutt.) Engelm.) genotypes. Based on isothermal microcalorimetric data, genotype NE91-118 (cultivar now known as ‘Prestige’) was less affected by low temperatures than either genotype 609 or UCD 95 in the −5 to −15 °C range suggesting greater cold hardiness for ‘Prestige’. Among the three genotypes tested, leaf and root segments of ‘Prestige’ froze at the lowest temperature, 609 was intermediate, and UCD 95 froze at the highest temperature. Scanning microcalorimetry showed that the freezing points of root segments were 7.5–8.8 °C higher than leaf segments for all three genotypes. Our results suggested that the lower freezing temperatures and the greater ability to maintain metabolic stability after exposure to low temperatures contributed to the higher degree of freezing tolerance of ‘Prestige’. Results indicated that calorimetry was an effective tool for determining low-temperature tolerance.