, Volume 88, Issue 1, pp 55–60

Growth schedule of Xanthium canadense: Does it optimize the timing of reproduction?


  • H. Sugiyama
    • Biological Institute, Faculty of ScienceTohoku University
  • T. Hirose
    • Biological Institute, Faculty of ScienceTohoku University
Original Papers

DOI: 10.1007/BF00328403

Cite this article as:
Sugiyama, H. & Hirose, T. Oecologia (1991) 88: 55. doi:10.1007/BF00328403


The effects of nutrition on the timing of reproductive initiation of a short-day annual plant Xanthium canadense (cocklebur) were examined with the following hypotheses in mind: If the plant always follows an optimal growth schedule, low-nutrient plants will initiate reproductive growth earlier than high-nutrient plants. On the other hand, if the plant flowers in response to photoperiodic stimuli, both plants will initiate reproductive growth on the same day. The sand-culture experiment showed that high-nutrient plants flowered earlier than the low-nutrient plants, leading to rejection of the first hypothesis. The predicted optimal flowering time is 2 days later than the actual flowering time in high-nutrient plants and 10 days earlier in low-nutrient plants. These deviations from the optimal times reduced the reproductive yield by 0.1% and 2.3%, respectively. The ratio of the final reproductive yield to the vegetative mass at flower initiation was 1.10 in high-nutrient plants and 0.63 in low-nutrient plants. Since the expected ratio for the optimal growth schedule is 1.0, high-nutrient plants followed the opitmal growth schedule more closely than the low-nutrient plants. Cocklebur is a fast-growing annual which is common in relatively nutrient-rich environments. This study suggests that cocklebur adapts itself to such environments through its photoperiodic response.

Key words

Annual plantNutritionOptimizationReproductive allocationXanthium canadense
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© Springer-Verlag 1991