The germination of Helonias bullata L. (Swamp pink) in response to flooded, saturated, and dry conditions

WCU Author/Contributor (non-WCU co-authors, if there are any, appear on document)
April Pallette Punsalan (Creator)
Western Carolina University (WCU )
Web Site:
Beverly Collins

Abstract: Poor sexual recruitment is a major conservation concern for the federally threatened, obligate wetland species Helonias bullata L. (swamp pink). Helonias predominately occurs in forested wetlands amongst hummock-hollow topography where water levels fluctuate spatially and temporally. This patchiness in moisture creates a high level of unpredictability in suitable microsites for germination and subsequent establishment. Germination percentages and rates were compared among seeds placed in flooded, saturated, and dry conditions in a controlled and natural environment for 1-35 days to determine how moisture conditions influence germination. In a controlled and natural environment, Helonias exhibited high final germination percentages (>50%) after all treatments, except dry conditions in the growth chamber. In addition, longer exposure to dry conditions both in a controlled and natural environment increased lag time before germination onset. Conversely, germination onset occurred earlier for seeds exposed to moisture treatments in a controlled (floating and submerged) and natural environment (stream margin, floating, and stream margin) for 3-30 days. For instance, after 13 days in a controlled environment, seeds floating (90%) and submerged (77%) germinated while in treatment. In the field, seeds floating (58%), submerged (3%), and in the stream margin (49%) germinated while in treatment after 20 days. Conversely, seeds "dry" (only exposed to rainwater) in the field after 20 days did not germinate while in treatment. Water dispersal may be an important part of Helonias regeneration niche because seeds exhibited high floating capability. Also, final germination percentages were significantly higher for seeds floating in comparison with seeds dry in the field. Overall, Helonias seeds exposed to moisture conditions (floating, submerged, and stream margin) germinated within a short time frame (10-30 days). Rapid germination when conditions are appropriate may be important for Helonias since it occurs in forested wetlands where spatial and temporal heterogeneity can create a narrow window for regeneration.

Additional Information

Language: English
Date: 2013
Federally Threatened, Forested Wetlands, Germination, Helonias bullata, Swamp Pink, Wetlands
Helonias bullata

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