Assessing post-harvest interim seed storage conditions: a case study of four boreal plant species

The longevity of seeds in storage is modulated by the initial quality as well as the storage conditions. Seeds of four boreal species were stored for a varying amount of time (0, 1, 2, 3 and 4 weeks) at 4 degrees C to determine the appropriate interim storage conditions after harvest and before processing. The highest germination of Solidago canadensis (75%), Shepherdia canadensis (79%) and Populus balsamifera (100%) seeds was observed for the four weeks at 4 degrees C treatment. However, P. tremuloides germination was reduced by 22.5% when seeds were kept at 4 degrees C for 3 or 4 weeks relative to the control; the reduction was less (1.5%) when seeds were kept at 4 degrees C for 1 or 2 weeks. No significant difference in mean germination time (MGT) or germination synchrony (SYN) was recorded following the different storage treatments and the control for Populus tremuloides or P. balsamifera. However, in Shepherdia canadensis, the MGT of the seeds in the 3-week treatment was longer, while in Solidago canadensis, the 3 or 4 weeks at 4 degrees C treatment improved the SYN relative to the control. The result suggests opportunities exist to store certain boreal seeds after harvest and before processing without reducing their germination characteristics.