Northern ragweed ecotypes flower earlier and longer in response to elevated CO₂: what are you sneezing at?

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• 作者：Kristina A. Stinson ; Jennifer M. Albertine ; Laura M. S. Hancock…
• 关键词：Ecotypes ; CO2 ; Phenology ; Plant ; Ragweed
• 刊名：Oecologia
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：182
• 期：2
• 页码：587-594
• 全文大小：788 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Ecology
  Plant Sciences
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1432-1939
• 卷排序：182

文摘

Significant changes in plant phenology and flower production are predicted over the next century, but we know relatively little about geographic patterns of this response in many species, even those that potentially impact human wellbeing. We tested for variation in flowering responses of the allergenic plant, Ambrosia artemisiifolia (common ragweed). We grew plants originating from three latitudes in the Northeastern USA at experimental levels of CO₂ (400, 600, and 800 µL L−1). We hypothesized that northern ecotypes adapted to shorter growing seasons would flower earlier than their southern counterparts, and thus disproportionately allocate carbon gains from CO₂ to reproduction. As predicted, latitude of origin and carbon dioxide level significantly influenced the timing and magnitude of flowering. Reproductive onset occurred earlier with increasing latitude, with concurrent increases in the number of flowers produced. Elevated carbon dioxide resulted in earlier reproductive onset in all ecotypes, which was significantly more pronounced in the northern populations. We interpret our findings as evidence for ecotypic variation in ragweed flowering time, as well in responses to CO₂. Thus, the ecological and human health implications of common ragweed’s response to global change are likely to depend on latitude. We conclude that increased flower production, duration, and possibly pollen output, can be expected in Northeastern United States with rising levels of CO₂. The effects are likely, however, to be most significant in northern parts of the region.