| 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 tight 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. |
| Genre: | Article |
| ProdID: | 1003204 |
| Citation Author: | Kimber, A. ; Korschgen, C. E. ; Van Der Valk, A.G. |
| Citation Contributing Office: | Upper Midwest Environmental Sciences Center |
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| Citation End Page: | 1973 |
| Citation Issue: | 12 |
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| Citation Language: | English |
| Citation Larger Work Title: | Canadian Journal of Botany |
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| Citation Number Of Pages: | 8 |
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| Citation Phsyical Description: | pp. 1966-1973 |
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| Citation Publisher: | Iowa State University, Botany Dept |
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| Citation Search Results Text: | The distribution of Vallisneria americana seeds and seedling light requirements in the upper Mississippi River; 1995; Article; Journal; Canadian Journal of Botany; Kimber, A. ; Korschgen, C. E. ; Van Der Valk, A.G. |
| Citation Start Page: | 1966 |
| Citation Volume: | 73 |
| Citation Year: | 1995 |
| Type: | citation/reference |
| Text: | The distribution of Vallisneria americana seeds and seedling light requirements in the upper Mississippi River; 1995; Article; Journal; Canadian Journal of Botany; Kimber, A. ; Korschgen, C. E. ; Van Der Valk, A.G. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Sun, 1 Jan 1995 00:00 -0600 |
| Publisher: | Iowa State University, Botany Dept |
