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[摘要]：Variation in flowering plant density can have conflicting effects on pollination and seed production. Dense flower patches may attract more pollinators, but flowers in those patches may also compete for pollinator visits and abiotic resources. We examined how natural and experimental conspecific flowering plant density affected pollen receipt and seed production in a protandrous, bumble bee-pollinated wildflower. Delphinium barbeyi (Ranunculaceae). We also compared floral sex ratios, pollinator visitation rates, and pollen limitation of wed set from early to title in the season to determine whether these factors mirrored seasonal changes in pollen receipt and wed production. Pollen receipt increased with natural floweing plant density, while seed production increased across lower densities and decreased across higher flower densities. Experimental manipulation of flowering plant density did not affect pollinator visitation rate, pollen receipt, or seed production. Although pollinator visitation rate increased 10-fold from early to late in the season, pollen receipt and seed set decreased over the season. Seed set was never pollen-limited. Thus despite widespread effects of flowering plant density oil plant reproduction in other species, the effects of conspecific flowering plant density on D. barbeyi pollination and seed production are minor. |
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