Sensitivity to green safelight of 12 Mediterranean species

In most germination experiments under dark conditions, green safelight is used to check the course of germination. However, there is evidence that even short exposures to such light can stimulate seeds to germinate. The extent of this effect is needed to determine if it is a generalization. The effect of green safelight was studied in a set of 12 Western Mediterranean species by testing germination responses to continuous darkness or to periodic short exposures to green safelight. Seeds were incubated at 15degreesC for 6 weeks. Half of the species showed significant effects of green safelight, the majority increasing as a result of safelight exposure. Cistaceae species seemed to be less sensitive to safelight than other families, like Compositae or Labiatae. Our results confirm that sensitivity to green safelight might be rather general and thus must be avoided when checking germination under darkness.