Insects introduced as biological control agents of diffuse knapweed, Centaurea diffusa, primarily reduce seed production. Knapweed densities appear to be resilient to greatly reduced seed production. We have used measurements of seedling density and survival, and production of seeds by flowering diffuse knapweed plants to develop functions for a model of knapweed populations. These simulations ...

We tested whether annual seed production (masting or mast fruiting) in Northern Hemisphere trees is an evolved strategy or a consequence of resource tracking by comparing masting patterns with those of annual rainfall and mean summer temperatures, two environmental variables likely to correlate with available resources. There were generally significant negative autocorrelations between the seed...

Pre-dispersal seed predation (PDSP) is commonly observed in woody plants, and recognized as a driver of seed production variability that is critical for successful regeneration. Earlier studies on PDSP and its determinants were mostly species specific, with community-level PDSP rarely estimated; and the interactions between the temporal variability of seed production and PDSP remain elusive. In...

This study was carried out to determine the effects of supplementing different levels (0, 0.5 and 1% of buffered rumen fluid) of methanolic extract of pomegranate peel, on rumen fermentation kinetics of four oil seed meals (soybean meal, cotton seed meal, rapeseed meal and sunflower seed meal), using in vitro gas production technique. The samples were incubated in syringes containing rumen liqu...

We use seed count data from a New Zealand mono-specific mountain beech forest to test for decadal trends in seed production along an elevation gradient in relation to changes in climate. Seedfall was collected (1965 to 2009) from seed trays located on transect lines at fixed elevations along an elevation gradient (1020 to 1370 m). We counted the number of seeds in the catch of each tray, for ea...

The response of seed production to CO(2) concentration ([CO(2)]) is known to vary considerably among C(3) annual species. Here we analyse the interspecific variation in CO(2) responses of seed production per plant with particular attention to nitrogen use. Provided that seed production is limited by nitrogen availability, an increase in seed mass per plant results from increase in seed nitrogen...

BACKGROUND AND AIMS Seed survival in the soil contributes to population persistence and community diversity, creating a need for reliable measures of soil seed bank persistence. Several methods estimate soil seed bank persistence, most of which count seedlings emerging from soil samples. Seasonality, depth distribution and presence (or absence) in vegetation are then used to classify a species'...

This paper considers strengths and weaknesses of the informal and formal seed as a basis for seed sector development. The informal seed sector is defined as the total of farmers’ seed production, selection and seed exchange activities. Farmers play an important role in seed supply but they are generally not considered as a partner in the seed sector. Seed produced by farmers is still the most i...

Previous studies demonstrated the effects of polyploidy on various aspects of plant life. It is, however, difficult to determine which plant characteristics are responsible for fitness differences between cytotypes. We assessed the relationship between polyploidy and seed production. To separate the effects of flowering phenology, flower head size and herbivores from other possible causes, we c...

Current research has determined that traits involved in reproductive strategies and processes of seed dynamics should be studied together, and under varying environments, in order to clarify their roles in the ecology of plant communities. Here, we analyzed reproductive traits (allocation to reproduction, efficiency of seed production, and seed size) at the community level and their relationshi...