Cold Tolerance and Antioxidant Response of Poa Pratensis and Paspalum vaginatum

A limiting factor for prodution of turf grasses in temperate regions is their low level of cold tolerance. In order to elucidate the cold tolerance, physiological and biochemical responses of two turf species, this study was conducted at a controlled environment greenhouse of Faculty of Agriculture in Shiraz University, Shiraz, Iran by a factorial experiment in completely randomized design with three replicates. Factors consisted of two turf species including Kentucky bluegrass (Poa pratensis) and seashore paspalum (Paspalum vaginatum) and four temperatures: 25, 15, 5 and -5 °C. Data analysis revealed that decreased temperature resulted in significant increases in proline, soluble sugars contents and activity of peroxidase, ascorbate peroxidase, catalase and superoxide dismutase enzymes, although seashore paspalum indicated a significant drop in antioxidant enzymes activity at cold stress of -5 °C. Furthermore, decreased temperature brought about a significant decline in visual quality, chlorophyll, starch and relative water content. Seashore paspalum exhibited a greater deterioration in visual quality, chlorophyll and relative water content at -5 °C compared to Kentucky bluegrass. The results showed that Kentucky bluegrass withstood cold stress with a better and more efficient defensive mechanism in comparison with seashore paspalum, thus it is considered more tolerant to cold stress and could, potentially, be used in temperate regions.