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Keywords:

  • Carex;
  • leaf senescence;
  • nutrient limitation;
  • nutrient retention;
  • resorption efficiency

Summary

  • 1
    Nitrogen or phosphorus limits plant growth in many wetlands. If specific mechanisms reducing losses of the growth-limiting nutrient have been favoured by selection, the N and P resorption efficiency (RE) during leaf senescence (NRE, PRE: the fraction of N or P resorbed) might depend on the type of nutrient limitation.
  • 2
    The size, mass, and N and P concentrations of green and senesced leaves were determined for 10 graminoid species at Dutch and Swiss wetland sites, with N : P ratios in leaves (6–27 by mass) indicating N or P limitation.
  • 3
    During senescence, leaf area decreased by 8–19%, and leaf mass by 8–38%; NRE ranged from 0 to 87%, and PRE from 30 to 96%. PRE correlated strongly with NRE (r = 0·91) but was, on average, 17% higher. Within the Swiss or Dutch sites, NRE and PRE did not correlate with foliar N : P ratios, indicating that RE was not directly adjusted to the type of nutrient limitation.
  • 4
    NRE and PRE were, on average, higher at the P-limited Swiss sites than at the N-limited Dutch sites. Because PRE exceeded NRE, high RE would be most beneficial when P limits plant growth. This may have contributed to the dominance of graminoids with high RE in P-limited wetlands.