The distribution of Vallisneria americana seeds and seedling light requirements in the Upper Mississippi River

Abstract

Vallisneria americana declined in backwaters of the Upper Mississippi River, U.S.A., after a drought in 1988. To determine whether viable seeds of V. americana occurred in the seed bank of navigation pool 7, Lake Onalaska, the upper 5 cm of sediment was collected from 103 sites in May 1990. These sediment samples were kept in pots at a depth of 0.4, 0.8, and 1.2 m in an outdoor pond for 12 weeks. Vallisneria americana seeds germinated from sites throughout the lake, and some seedlings produced overwintering buds by the end of the study. Seeds, spores, or fragments of 12 other species of aquatic plants also germinated. Seed germination trials with fresh and stored seeds in both greenhouse and ponds in which light availability was reduced with shade cloths indicated that seed germination was insensitive to light level. To determine the light requirements for seedling survival and bud production, sediment from Lake Onalaska was incubated in ponds under neutral density shade screens reducing light to 2, 5, 9, and 25% of full sun. Seeds germinated under all shade treatments but survival was significantly higher in the 9 and 25% light treatments, and bud production was restricted to these light levels.

Composition of the seed bank in drawdown areas of Navigation Pool 8 of the Upper Mississippi River

“…and L. dubia ranked within the top five most dominant taxa for each of the seedbanks (Table IV). Other published accounts of UMR seed banks have been limited to aquatic species (Kimber et al, 1995;McFarland and Rogers, 1998) for UMR Navigation Pool 7 (Lake Onalaska). The arrays of submersed aquatic plant species that germinated in these studies are comparable to that found in this study.…”

Long-term studies of crayfish-invaded lakes reveal limited potential for macrophyte recovery from the seed bank

“…A lack of suitable germination cues also could help explain why some species did not appear in the greenhouse assays (Stroh et al 2012). McFarland and Rogers (1998) had good success germinating seeds in a low-alkalinity culture solution (but see Kimber et al 1995). However, in most studies we encountered, investigators using the emergence method did not apply a chemical treatment to stimulate germination (e.g., Haag 1983, Bonis and Lepart 1994, ter Heerdt et al 1996, Stroh et al 2012.…”

Restoration of the Cirsio dissecti-Molinietum in The Netherlands: Can we rely on soil seed banks?

“…McFarland and Rogers (1998) had good success germinating seeds in a low-alkalinity culture solution (but see Kimber et al 1995). However, in most studies we encountered, investigators using the emergence method did not apply a chemical treatment to stimulate germination (e.g., Haag 1983, Bonis and Lepart 1994, ter Heerdt et al 1996, Stroh et al 2012.…”