| Popis: |
Summary Seeds of 32 montane species were collected throughout northern Scotland. Germination responses, particularly the effects of chilling on breaking dormancy, were examined using a serial test incorporating single- and double-chilling treatments, alternating 20°C/10°C incubation temperatures, gibberellic acid and, for some species, nicking of the seed coat. Where practicable, any ungerminated seeds were ultimately dissected to assess their viability. Only three species had an absolute requirement for pre-chilling before seeds germinated. A further eight species required chilling to break the dormancy of 15% or more seeds; otherwise chilling generally increased the extent and rate of germination. Unusually, chilling induced dormancy in the seeds of four species whereas warm conditions induced dormancy which was not broken by subsequent chilling amongst seeds of Draba incana. Germinability and germination rates for nine species were regressed on the altitude, latitude and oceanicity of the plants' origi... |
