Seed dormancy and germination are complex adaptive traits of higher plants that are influenced by a large number of genes and environmental factors. Studies of genetics and physiology have shown the important roles of the plant hormones abscisic acid and gibberellin in the regulation of dormancy and germination. More recently, the use of quantitative genetics and mutant approaches has allowed t...

We propose using plant microcommunities emerging from soil seed banks as experimental systems for studing species richness. We gathered soil from four Oklahoma terrestrial habitats, kept the soil moist in pots in a greenhouse, and allowed plants to germinate and interact under different conditions. Although heterogeneity among samples was minimized, we observed the often-reported unimodal relat...

Seed dormancy and germination are complex adaptive traits of higher plants that are influenced by a large number of genes and environmental factors. Studies of genetics and physiology have shown the important roles of the plant hormones abscisic acid and gibberellin in the regulation of dormancy and germination. More recently, the use of quantitative genetics and mutant approaches has allowed t...

The accumulation of mildly deleterious mutations accompanying recurrent regeneration of plant germ plasm was modeled under regeneration conditions characterized by different amounts of selection and genetic drift. Under some regeneration conditions (sample sizes >75 individuals and bulk harvesting of seed) mutation accumulation was negligible, but under others (sample sizes <75 individuals or e...

Tropical pastures present multiple barriers to tree regeneration and restoration. Relict trees serve as "regeneration foci" because they ameliorate the soil microclimate and serve as safe spots for dispersers. Here, we describe another mechanism by which remnant trees may facilitate pasture regeneration: the presence of seed banks in the canopy soil that accumulates from decomposing epiphytes w...

Plant genetic resources for food and agriculture are ex situ conserved in germplasm banks as samples (accessions) of natural or naturalized populations, either the originally sampled propagules (mainly seeds) their multiplications. The premises underlying conservation that (a) it is safest cheapest alternative preservation future generations (b) accessions representative diversity encountered n...

Most ecological studies of fungi associated with tropical plants have focused on the rhizosphere or phyllosphere of seedlings, saplings and adult trees (Augspurger 1983, 1984; Bell et al. 2006, Gilbert 2002, Gilbert et al. 2002, Husband et al. 2002, Kiers et al. 2000, Mangan et al. 2004). However, fungi also infect the seeds of tropical trees, reducing seed survival and potentially affecting ad...

Fertilizer amendments can impact weed populations in a variety of ways. This study evaluated the effects of 12 year-long applications of different fertilization systems on size and composition of the weed seed bank in a conventionally managed maize monoculture field. Fertilization systems included all factorial combinations of two dairy cattle slurry rates, three vegetable, fruit and garden was...

Forest succession on degraded tropical lands often is slowed by impoverished seed banks and low rates of seed dispersal. Within degraded landscapes, remnant forests are potential seed sources that could enhance nearby forest succession. The spatial extent that forest can influence succession, however, remains largely unstudied. In abandoned agricultural lands in Kibale National Park, Uganda, re...

seed deterioration is loss of seed quality, viability and vigor due to effect of adverse environmental factors. many of our crops are reproduced through seeds, and throughout the world large quantities are produced, stored and transported. seed ageing during storage may cause retardation of field establishment, and may eventually result in seedling abnormalities or even failure of emergence. du...