Studies in Festuca. X. Observations on germination and seedling cold tolerance in diploid Festuca pratensis and tetraploid F. pratensis var. apennina in relation to their altitudinal distribution.
Populations were collected from twelve sites in Switzerland and Italy. Tetraploids occurred in grassland at high altitudes but in woodlands down to 1100 m; below this only the diploid was found. The distribution of diploids and tetraploids overlapped in the woodland zone between 1100 and 1600 m, but, where mean winter temperatures were above -2 deg C or below -5 deg C, no tetraploids or diploids, respectively, were found. In tests under controlled conditions, a low-temperature pretreatment enhanced the germination of tetraploids. Cold damage of seedlings was assessed in seedlings hardened for five weeks at 5 deg C and then frozen for 6-12 h at -3 to -5 deg C. Overall, 54% of diploid seedlings and 7% of tetraploids were surviving when examined eight days after these treatments. [See PBA 47, 7491 & 11595].