Heat tree/shrub seeds before sowing: freshwater wetlands
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
Background information and definitions
Heating seeds before planting can help to break seed dormancy and encourage germination. Seeds of some species (with physiological dormancy) must experience high temperatures before germinating, in order to break down chemicals that inhibit germination or stop the production of these chemicals. For other species (with physical dormancy), heat can increase the permeability of the seed coat to water and gases, which are essential for germination. For a database of seed dormancy class by species, see Baskin & Baskin (2014).
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 heating baldcypress Taxodium distichum seeds in a flame reduced their germination rate. Heated seeds had a lower germination rate (0% germinated) than unheated seeds (47% germinated). 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 held in a gas flame for 3 sec before soaking.Study and other actions tested