Seed Production and Seed Mortality in a Temperate Forest Shrub (Witch- Hazel, Hamamelis Virginiana)

1982 ◽  
Vol 70 (2) ◽  
pp. 437 ◽  
Author(s):  
Diane De Steven
Keyword(s):  
Seed Production ◽  
Temperate Forest ◽  
Witch Hazel ◽  
Seed Mortality

Context-specific enhanced invasiveness of Raphanus crop–wild hybrids: A test for associations between greater fecundity and population growth

2014 ◽  
Vol 94 (8) ◽  
pp. 1315-1324 ◽  
Author(s):  
Lesley G. Campbell ◽  
Zachary Teitel ◽  
Maria N. Miriti ◽  
Allison A. Snow
Keyword(s):  
Population Growth ◽  
Seed Production ◽  
Plant Density ◽  
Genotypic Differences ◽  
Raphanus Raphanistrum ◽  
Invasive Potential ◽  
Population Growth Rates ◽  
Seed Mortality ◽  
Wild Hybrid ◽  
Context Specific

Campbell, L. G., Teitel, Z., Miriti, M. N. and Snow, A. A. 2014. Context-specific enhanced invasiveness of Raphanus crop–wild hybrids: A test for associations between greater fecundity and population growth. Can. J. Plant Sci. 94: 1315–1324. Evolution by crop–wild hybridization may create plant lineages with greater population growth rates, dispersal, and persistence than weedy progenitors, depending upon plant density. We asked: (1) how does hybridization affect demography and population growth rate (lambda, λ) and (2) how does density affect demography and λ? Over 1 yr, we followed wild radish, Raphanus raphanistrum and crop-wild hybrid, Raphanus sativus×R. raphanistrum, plants grown in 18 experimental sub-populations (originally derived from three wild and three hybrid populations) to assess contributions of germination, survival, and seed production to λ. We explored genotypic differences in demographic characteristics of low- and high-density populations (from populations grown at unmanipulated densities for three generations), using a LTRE. Hybrid populations had greater λs than weedy progenitors when grown in low (but not high) densities. Seed production was more influential on λ than germination or survival, and seed mortality was least influential. Our results indicate weedy Raphanus populations may be best controlled by limiting seed production, rather than killing plants outright or preventing seeds from germinating. Furthermore, relative invasiveness of genotypes is density-dependent, low-density conditions improving potential invasiveness of hybrid populations. We emphasize that assessing invasive potential of a plant will be more successful if one uses a comprehensive demographic approach accounting for a weed's entire life history.

scholarly journals The biology of the annual Salicornia europaea agg. at the limits of its range in Hudson Bay

1983 ◽  
Vol 61 (3) ◽  
pp. 762-773 ◽  
Author(s):  
R. L. Jefferies ◽  
A. Jensen ◽  
D. Bazely
Keyword(s):  
Seed Production ◽  
Surface Sediments ◽  
Hudson Bay ◽  
Salicornia Europaea ◽  
Marginal Populations ◽  
Marginal Population ◽  
Seed Mortality ◽  
The Difference ◽  
Intertidal Site ◽  
Adult Plants

The biology of a marginal population of the annual Salicornia europaea agg. has been examined at La Pérouse Bay, Manitoba, on the shores of Hudson Bay. Plants were confined to south-facing sites which became hypersaline in summer, but which were not covered by tides. The difference in temperature of surface sediments between south- and north-facing slopes was as much as 7 °C. Although most seedlings emerged in June, germination continued throughout the summer, but plants that appeared late in the season failed to set seed. Mortality of both seedlings and adult plants was low. Seeds or seedlings from a south-facing slope were transplanted during a 2-year period within the same site, into another south-facing site, to a north-facing site, and to an intertidal site. Germination either failed to occur or else was poor at the latter two sites. In addition, seed production of mature plants was low compared with that for individuals transplanted within south-facing sites. Additions of nitrogen to north-facing slopes increased overall seed output per plant, but the ratio of unripened to ripened seeds remained the same as that in plants from untreated plots. The results are discussed in relation to the ecology of marginal populations.

Some insects affecting Penstemon seed production

2012 ◽  
Vol 13 (2) ◽  
pp. 107-111
Author(s):  
R. Hammon ◽  
M. Franklin
Keyword(s):  
Seed Production
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