Seed dormancy break and germination for restoration of three globally important wetland bulrushes

Published source details Marty J.E. & Kettenring K.M. (2017) Seed dormancy break and germination for restoration of three globally important wetland bulrushes. Ecological Restoration, 35, 138-147.
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This study is summarised as evidence for the following.

	Action	Category
	Soak seeds of non-woody plants before sowing: freshwater wetlands Action Link
	Chill seeds of non-woody plants before sowing: freshwater wetlands Action Link
	Treat seeds of non-woody plants with chemicals before sowing: freshwater wetlands Action Link
	Chill seeds of non-woody plants before sowing: freshwater wetlands Action Link

Soak seeds of non-woody plants before sowing: freshwater wetlands

A replicated, randomized, controlled study in 2015 in a greenhouse in Utah, USA (Marty & Kettenring 2017) found that soaking seeds of three bulrush species in water typically had no significant effect on their germination rate. Seeds that had been soaked before sowing had statistically similar germination rate in 24 of 30 comparisons (for which soaked: 6–88%; unsoaked: 1–75%). In the other six comparisons, soaked seeds had a higher germination rate (18–69%) than unsoaked seeds (4–50%). Five of these comparisons involved seeds whose dormancy had previously been broken through chilling and/or chemical treatments. Methods: Field-collected seeds of three bulrush species were sown onto sand in the greenhouse (36–72 sets of seeds/species; ≥100 seeds/set). Seeds in 18–36 random sets/species were soaked for two weeks before planting (in deionized water, changed every three days, 28–35°C). The other sets were kept dry. Some sets were also chilled and/or soaked in chemicals before soaking in water. After sowing, seeds were kept saturated. Germination rates for each set were recorded five weeks after sowing.

(Summarised by: Nigel Taylor)
Chill seeds of non-woody plants before sowing: freshwater wetlands

A replicated, randomized, paired, controlled study in 2015 in a laboratory in Utah, USA (Marty & Kettenring 2017) found that chilling seeds of three bulrush species either increased or had no significant effect on their germination rate, depending on the duration of chilling. Seeds that had been chilled for 180 days before sowing had a higher germination rate than unchilled seeds in 14 of 18 comparisons (for which chilled: 22–90%; unchilled: 0–66%). However, seeds that had been chilled for 30 days before sowing had a statistically similar germination rate to unchilled seeds in 16 of 18 comparisons (for which chilled: 0–62%; unchilled: 0–77%). Chilling seeds never significantly increased the germination rate of one of the species, threesquare bulrush Schoenoplectus americanus (four of four comparisons; chilled: 61–77%; unchilled: 50–75%). Methods: Field-collected seeds of three bulrush species were sown into petri dishes filled with sand (16–64 dishes/species; ≥50 seeds/dish). There were 4–16 dishes/species for each of four pre-sowing temperature treatments: chilling (4°C) for 30 or 180 days, or room temperature for 30 or 180 days. Replicates were split across two incubators. After sowing, dishes were kept saturated or flooded and incubated at 18–35°C. Germination rates for each dish were recorded four weeks after sowing.

(Summarised by: Nigel Taylor)
Treat seeds of non-woody plants with chemicals before sowing: freshwater wetlands

A replicated, randomized, controlled study in 2015 in a greenhouse in Utah, USA (Marty & Kettenring 2017) found that soaking seeds of three bulrush species in acid or bleach typically increased or had no significant effect on their germination rate, with the precise effect depending on factors such as the chemical used, whether seeds were chilled after soaking, bulrush species and source site. Seeds that had been soaked in bleach before sowing had a higher germination rate than unbleached seeds in 9 of 20 comparisons (for which bleached: 32–74%; unbleached: 2–25%). This included 9 of 10 comparisons involving seeds that were kept at room temperature (not chilled) before planting. Bleached and unbleached seeds had statistically similar germination rates in 8 of the 20 comparisons (for which bleached: 39–68%; unbleached: 27–58%). Seeds that had been soaked in acid before sowing had a statistically similar germination rate to unsoaked seeds in 20 of 20 comparisons (for which acid-soaked: 2–88%; unsoaked: 2–88%). Methods: Field-collected seeds of three bulrush species were sown onto sand in the greenhouse (36–72 sets of seeds/species; ≥100 seeds/set). There were 12–24 sets/species for each of three pre-sowing chemical treatments: soaking in 3% diluted household bleach for 48 h, soaking in 2.7% sulfuric acid for 40 min, or none. Some sets were also chilled and/or soaked in water after chemical treatments. After sowing, seeds were kept saturated and at 28–35°C. Germination rates for each set were recorded five weeks after sowing.

(Summarised by: Nigel Taylor)
Chill seeds of non-woody plants before sowing: freshwater wetlands

A replicated, randomized, controlled study in 2015 in a greenhouse in Utah, USA (Marty & Kettenring 2017) found that chilling seeds of three bulrush species either increased or had no significant effect on their germination rate, with the precise effect depending on factors such as the species, source site and whether seeds were soaked in chemicals before chilling. Seeds that had been chilled before sowing had a higher germination rate than unchilled seeds in 17 of 30 comparisons (for which chilled: 35–88%; unchilled: 2–26%). This included 9 of 10 comparisons involving seeds that had not been chemically treated before chilling. Chilled seeds had a similar germination rate to unchilled seeds in the other 13 of 30 comparisons (for which chilled: 28–69%; unchilled: 2–75%). This included 10 of 10 comparisons involving seeds that had been soaked in bleach before chilling. Methods: Field-collected seeds of three bulrush species were sown onto sand in the greenhouse (36–72 sets of seeds/species; ≥100 seeds/set). Seeds in 18–36 random sets/species were chilled at 4°C for 30 days before sowing. The other sets were kept at room temperature. Some sets were also soaked in acid, bleach and/or water before or after chilling. After sowing, seeds were kept saturated and at 28–35°C. Germination rates for each set were recorded five weeks after sowing.

(Summarised by: Nigel Taylor)