Physically damage tree/shrub seeds before sowing: freshwater wetlands
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
Background information and definitions
Damaging, weakening or softening the coating of seeds before planting can help to break seed dormancy and encourage germination. For species with physical dormancy, damage to the seed coat can increase its permeability to water and gases, which are essential for germination. For a database of seed dormancy class by species, see Baskin & Baskin (2014).
This action includes mechanically damaging seeds (e.g. by rubbing them with sandpaper or nicking them with a knife) and removing excess tissues from around the seed (e.g. the sac-like perigynia around sedge seeds). To be summarized as evidence for this action, studies must have explicitly compared the performance of treated and untreated seeds. Studies that simply report the performance of treated seeds are not summarized here. Studies do not have to be in flooded/saturated soils, as long as they involve wetland-characteristic species.
Baskin C.C. & Baskin J.M. (2014) Seeds: Ecology, Biogeography and Evolution of Dormancy and Germination, Second Edition. Academic Press.
Supporting evidence from individual studies
A replicated, controlled study in 2004 in a laboratory in Florida, USA (Liu et al. 2009) found that cutting baldcypress Taxodium distichum seeds in half reduced their germination rate but had no significant effect on seedling growth. Seeds that had been cut in half had a lower germination rate (20% germinated) than whole seeds (48% germinated). After 30 days, there was no significant difference in the height of seedlings that had grown from cut seeds (8.3 cm) or whole seeds (8.3 cm). Methods: In August 2004, sixty baldcypress seeds were planted into trays of growing medium. All seeds had been stored at 4°C for four months before the experiment started, and soaked in distilled water for 24 h before planting. Thirty seeds (three replicates of 10 seeds) had also been cut in half with scissors before soaking. Germinated seedlings were transplanted to individual pots of growing medium and measured after 30 days.Study and other actions tested