Effects of storage conditions on dormancy and vigor of Picea abies seeds

The dormancy and vigor of Picea abies seeds were studied after five months of storage at 25 and 75% relative humidity (RH) and 5 and 12 degrees C. Dor mancy was evaluated by studying germination response to light and moist chi lling at 12 and 21 degrees C. Dormancy causing germination reduction in the dark was induced in seeds during storage at 25% RH (5-6% moisture content, MC) in darkness. The dormancy was greater when seeds were germinated at 12 than at 21 degrees C and after storage at 12 than at 5 degrees C. The effe ctive dormancy relief by light indicates that germination was under phytoch rome control. Moist chilling could partly replace light. According to accel erated aging and leachate conductivity tests, dry seeds could be stored at 12 degrees C for five months without affecting their vigor. After storage a t 75% RH(11% MC) and 5 degrees C, the seeds germinated slowly and incomplet ely. The decreased germination response to light indicates that other proce sses than those mediated directly by phytochrome restricted germination of these seeds. The positive germination response to moist chilling suggested that secondary dormancy was induced in the seeds. However, vigor tests gave some evidence of simultaneous decrease of vigor. Storage at 75% RH and 12 degrees C decreased germination nearly to 0%. Germination of seeds stored a t 75% RH could be stimulated by a short accelerated aging period.